Stress corrosion cracking of superplastically formed 7475 aluminum alloy

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12 Hydrogen-Induced Cracking and sulfide stress cracking

Blister
Unstressed
(HIC1 SWC)
Stressed
SOHIC
Stressed
SSC
FIGURE 1. Schematic presentation of various hydrogen-induced cracks in steel.
H2S * HS -I- H* Cathodic Reaction 2H* + 2c -2H
L£ Hydrogen-Induced Cracking and Sulfide Stress Cracking
M. ELBOUJDAINI
CANMET Materials Technology Laboratory Ottawa, Ontario, Canada
A. INTRODUCTION The four main environmental cracking phenomena of concern [1-5] when steels are exposed to wet H2S environments are 1. 2. 3. 4. Hydrogen blistering: Blister formation, originating at nonmetallic inclusions. Hydrogen-induced cracking (HIC): Also known as stepwise cracking (SWC). Stress-oriented hydrogen-induced cracking (SOHIC). Sulfide stress cracking (SSC): Cracking in steels of high strength or high hardness.

考虑裂纹扩展的周向裂纹损伤圆柱壳的极限强度

件下的圆柱壳类基本构件的极限强度。
对于海洋平台中的圆柱壳构件，依其受力状态，周向壁穿裂纹更为常见且更危险。针对这类裂纹损伤构件的极限强度的计算通常是采用所谓裂纹截面全塑性法【。该方法简单地以扣除裂纹表面积后１］的截面剩余面积上的全塑性内力来推算极限强度，因此裂纹扩展的影响无法考虑，即可能过高地估计结构的极限强度。另一种更为简单的方法是以裂纹起裂时的结构强度作为其极限强度，对于具有足够韧性的钢材而言，显然这也是近似和保守的。要想合理地评估含裂纹损伤构件的极限强度，考虑裂纹扩展对结构强度的影响是必要的。如果考虑裂纹扩展，不难想到，结构的极限强度会受到裂纹尖端张开位移ＣＯＤ和裂纹尖端张开角度ＣＯ等断裂参数的影响。与受结构的几何尺度影响较小的应力或ＴＴＡ
数对极限强度的影响，并就其对各参数的敏感度作相应的分析；同时提出极限强度损失系数、强度冗
余系数及裂纹剩余扩展长度等无因次参数，并以此对由裂纹扩展所引起的结构承载能力的变化给
出定量的评价。
１计算模型、计算方法及验证
１１计算模型．
考虑裂纹扩展的周向裂纹损伤圆柱壳的极限强度
何书韬，赵耀，袁华
（华中科技大！学船舶与海洋＿程学院，武汉，４０７）Ｔ－３０４
摘
要

腐蚀和酸性环境选材ISO_15156-2009

SOHIC（stress-oriented hydrogen-induced cracking）应
力导向性氢致开裂 SCC(stress corrosion cracking) 应力腐蚀开裂 HSC（hydrogen stress cracking）氢应力开裂 SZC（soft-zone cracking）软区开裂 SWC（Step-wise cracking)阶梯裂纹 CRA（ Corrosion-resistant alloy)耐蚀合金 HRC（Rockwell hardness）洛氏硬度 HBW (Brinell hardness) 布氏硬度 HV (Vickers hardness) HZC（Heat-affected zone) 热影响区 SOUR SERVICE: exposure to oilfield environments that contain sufficient H2S to cause cracking of materials by the mechanisms addressed by this part of ISO 15156
三标准术语
SSC(sulfide stress-cracking) 硫化物应力开裂 cracking of metal involving anodic processes of localized
corrosion and tensile stress (residual and/or applied) in the presence of water and H2S （在有水和硫化氢存在的情况下，与腐蚀和拉应力有关的一种金属开裂）
四标准适用范围
石油天然气生产以及脱硫装置中处于硫化氢环境中设备的

催化裂化再生设备应力腐蚀特征分析

试验研究文章编号:100027466(2002)0120020204催化裂化再生设备应力腐蚀特征分析Ξ程光旭1,朱继刚1,朱文胜2,鱼　济2(1.西安交通大学环境与化工学院,陕西西安　710049;2.兰州炼油厂设备研究所,甘肃兰州　730060)摘要:调查分析了国内炼油厂催化裂化装置中再生器的应力腐蚀现状,结合兰州炼油化工厂重油催化裂化再生器的运行工艺和介质等参数,分析了再生器应力腐蚀的特征,并探讨了实际生产中有效的应力腐蚀防护措施。

关　键　词:催化;再生器;应力腐蚀中图分类号:TQ052 文献标识码:ACharacteristics analysis of stress corrosion in catalytic cracking reclaiming equipmentCHEN G Guang2xu1,ZHU Ji2gang1,ZHU Wen2sheng2,YU Ji2(1.Xi’an Jiaotong University,Xi’an710049,China;nzhou Petroleum Processing EquipmentResearch Institute,Lanzhou730060,China)Abstract:Investigation of stress corrosion in catalytic cracking reclaiming equipment was carried out.The refinery pro2 cessing and medium parameters were measured in Lanzhou Petroleum Processin g and Chemical Complex SINOPEC.The characteristics of stress corrosion were analyzed as well.Finally,the measurementc of corrosion protection were presented.K ey w ords:catalysis;regenerator;stress corrosion 炼油厂催化裂化装置(FCCU)通常以重质馏分油为原料,用硅酸铝等作催化剂,在反应器中进行裂化反应,以制取汽油、轻柴油等。

弹性力学专业英语英汉互译词汇

elasticitytheory of elasticity homogeneous state ofstressstress invariant strain invariant strain ellipsoid homogeneous state ofstrainequation of strain compatibilityLame constants isotropic elasticityrotating circular diskwedgeKelvin problemBoussinesq problemAiry stress functionKolosoff-Muskhelishvili methodKirchhoff hypothesisPlateRectangular plate Circular plate Annular plate Corrugated plate Stiffened plate,reinforced弹性力学弹性理论均匀应力状态应力不变量应变不变量应变椭球均匀应变状态应变协调方程拉梅常量各向同性弹性旋转圆盘楔开尔文问题布西内斯克问题艾里应力函数克罗索夫―穆斯赫利什维利法基尔霍夫假设板矩形板圆板环板波纹板加劲板PlatePlate of moderate thickness Stress function of bendingShell Shallow shell Revolutionary shell Spherical shell Cylindrical shell Conical shell Toroidal shell Closed shell Corrugated shell Stress function of torsionWarping function semi-inverse method Rayleigh-Ritz method Relaxation methodLevy method Relaxation Dimensional analysis self-similarity Influence surface Contact stress Hertz theory Conforming contact Sliding contact Rolling contact中厚板弯［曲］应力函数壳扁壳旋转壳球壳［圆］柱壳锥壳环壳封闭壳波纹壳扭［转］应力函数翘曲函数半逆解法瑞利―里茨法松弛法莱维法松弛量纲分析自相似［性］影响面接触应力赫兹理论协调接触压入Indentation各向异性弹性Anisotropic elasticity 颗粒材料Granular material散体力学Mechanics of granular media 热弹性Thermoelasticity超弹性Hyperelasticity粘弹性Viscoelasticity对应原理Correspondence principle 褶皱Wrinkle塑性全量理论Total theory of plasticity 滑动Sliding微滑Microslip粗糙度Roughness非线性弹性Nonlinear elasticity 大挠度Large deflection突弹跳变snap-through有限变形Finite deformation格林应变Green strain阿尔曼西应变Almansi strain弹性动力学Dynamic elasticity运动方程Equation of motion准静态的Quasi-static气动弹性Aeroelasticity水弹性Hydroelasticity颤振Flutter弹性波Elastic wave简单波Simple wave柱面波Cylindrical wave水平剪切波Horizontal shear wave 竖直剪切波Vertical shear wave 体波body wave无旋波Irrotational wave 畸变波Distortion wave膨胀波Dilatation wave瑞利波Rayleigh wave等容波Equivoluminal wave 勒夫波Love wave界面波Interfacial wave 边缘效应edge effect塑性力学Plasticity可成形性Formability金属成形Metal forming耐撞性Crashworthiness结构抗撞毁性Structural crashworthiness 拉拔Drawing破坏机构Collapse mechanism回弹Springback挤压Extrusion冲压Stamping穿透Perforation层裂Spalling塑性理论Theory of plasticity 安定［性］理论Shake-down theory 运动安定定理kinematic shake-downtheoremStatic shake-down theorem rate dependent theoremload factor Loading criterion Loading function Loading surface Plastic loading Plastic loading waveSimple loading Proportional loadingUnloading Unloading wave Impulsive load step load pulse load limit load nentral loading instability in tension acceleration wave constitutive equation complete solution nominal stress over-stress true stress equivalent stressflow stress stress discontinuity静力安定定理率相关理论载荷因子加载准则加载函数加载面塑性加载塑性加载波简单加载比例加载卸载卸载波冲击载荷阶跃载荷脉冲载荷极限载荷中性变载拉抻失稳加速度波本构方程完全解名义应力过应力真应力等效应力流动应力应力间断stress space principal stress space hydrostatic state of stresslogarithmic strain engineering strain equivalent strain strain localizationstrain ratestrain rate sensitivitystrain space finite strain plastic strain incrementaccumulated plastic strainpermanent deformationinternal variable strain-softening rigid-perfectly plasticMaterialrigid-plastic materialperfectl plastic material stability of material deviatoric tensor of strain deviatori tensor of stress spherical tensor of strain spherical tensor of stresspath-dependency linear strain-hardening应力空间主应力空间静水应力状态对数应变工程应变等效应变应变局部化应变率应变率敏感性应变空间有限应变塑性应变增量累积塑性应变永久变形内变量应变软化理想刚塑性材料刚塑性材料理想塑性材料材料稳定性应变偏张量应力偏张量应变球张量应力球张量路径相关性strain-hardening kinematic hardening isotropic hardening strain-hardening moduluspower hardening plastic limit bendingMomentplastic limit torque elastic-plastic bending elastic-plastic interface elastic-plastic torsionViscoplasticityInelasticityelastic-perfectly plasticMaterial limit analysislimit design limit surface upper bound theorem upper yield point lower bound theorem lower yield point bound theorem initial yield surface subsequent yield surface convexity of yield surface shape factor of cross-section应变强化随动强化各向同性强化强化模量幕强化塑性极限弯矩塑性极限扭矩弹塑性弯曲弹塑性交界面弹塑性扭转粘塑性非弹性理想弹塑性材料极限分析极限设计极限面上限定理上屈服点下限定理下屈服点界限定理初始屈服面后继屈服面屈服面［的］外沙堆比拟屈服屈服条件屈服准则屈服函数屈服面塑性势能量吸收装置能量耗散率塑性动力学塑性动力屈曲塑性动力响应塑性波运动容许场静力容许场流动法则速度间断滑移线滑移线场移行塑性铰塑性增量理论米泽斯屈服准则普朗特―罗伊斯关系特雷斯卡屈服准则sand heap analogyYieldyield conditionyield criterionyield functionyield surfaceplastic potential energy absorbing device energy absorbing device dynamic plasticity dynamic plastic buckling dynamic plastic response plastic wave kinematically admissibleFieldstatically admissibleFieldflow rule velocity discontinuityslip-linesslip-lines field travelling plastic hinge incremental theory ofPlasticityMises yield criterion prandtl- Reuss relation Tresca yield criterion洛德应力参数莱维―米泽斯关系亨基应力方程赫艾一韦斯特加德应力空间洛德应变参数德鲁克公设盖林格速度方程结构力学结构分析结构动力学拱三铰拱抛物线拱圆拱穹顶空间结构空间桁架雪载［荷］风载［荷］土压力地震载荷弹簧支座支座位移支座沉降Lode stress parameterLevy-Mises relation Hencky stress equation Haigh-Westergaardstress space Lode strain parameter Drucker postulateGeiringer velocityEquation structural mechanics structural analysis structural dynamicsArchthree-hinged archparabolic archcircular archDomespace structurespace trusssnow loadwind loadearth pressureearthquake loadingspring support support displacementsupport settlementdegree of indeterminacy kinematic analysis method of joints method of sectionsjoint forces conjugate displacementinfluence line three-moment equation unit virtual force stiffness coefficient flexibility coefficientmoment distributionmoment distribution methodmoment redistribution distribution factor matri displacement method element stiffness matrix element strain matrix global coordinates Betti theorem Gauss-Jordan eliminationMethod buckling mode mechanics of compositescomposite materialfibrous composite unidirectional composite超静定次数机动分析结点法截面法结点力共轭位移影响线三弯矩方程单位虚力刚度系数柔度系数力矩分配力矩分配法力矩再分配分配系数矩阵位移法单元刚度矩阵单元应变矩阵总体坐标贝蒂定理高斯一若尔当消去法屈曲模态复合材料力学复合材料foamed composite particulate compositeLaminate sandwich panel cross-ply laminate angle-ply laminatePlycellular solid ExpansionDebulk Degradation DelaminationDebond fiber stress ply stress ply strain interlaminar stress specific strength strength reduction factor strength -stress ratio transverse shear modulustransverse isotropyOrthotropyshear lag analysis chopped fiber continuous fiber fiber direction泡沫复合材料颗粒复合材料层板夹层板正交层板斜交层板层片多胞固体膨胀压实劣化脱层脱粘纤维应力层应力层应变层间应力比强度强度折减系数强度应力比横向剪切模量横观各向同性正交各向异剪滞分析短纤维长纤维fiber break fiber pull-out fiber reinforcementDensification optimum weight design netting analysis rule of mixture failure criterion Tsai-W u failure criterionDugdale model fracture mechanics probabilistic fractureMechanicsGriffith theory linear elastic fracturemechanics, LEFMelastic-plastic fracturemecha-nics, EPFMFracture brittle fracturecleavage fracture creep fracture ductile fracture inter-granular fracture quasi-cleavage fracture trans-granular fractureCrack纤维断裂纤维拔脱纤维增强致密化最小重量设计网格分析法混合律失效准则蔡一吴失效准则达格代尔模型断裂力学概率断裂力学格里菲思理论线弹性断裂力学弹塑性断裂力学断裂脆性断裂解理断裂蠕变断裂延性断裂晶间断裂准解理断裂裂纹Flaw Defect Slit MicrocrackKinkelliptical crack embedded crack penny-shape crackPrecrack short crack surface crack crack blunting crack branching crack closure crack front crack mouthcrack opening angle,COAcrack opening displacement,CODcrack resistancecrack surfacecrack tipcrack tip opening angle,CTOAcrack tip openingdisplacement, CTOD crack tip singularity裂缝缺陷割缝微裂纹折裂椭圆裂纹深埋裂纹［钱］币状裂纹预制裂纹短裂纹表面裂纹裂纹钝化裂纹分叉裂纹闭合裂纹前缘裂纹嘴裂纹张开角裂纹张开位移裂纹阻力裂纹面裂纹尖端裂尖张角裂尖张开位移Fieldcrack growth rate stable crack growth steady crack growth subcritical crack growthcrack retardation crack arrest arrest toughness fracture mode sliding mode opening mode tearing mode mixed mode Tearingtearing modulus fracture criterionJ-integral J-resistance curve fracture toughness stress intensity factor Hutchinson-Rice-RosengrenFieldconservation integraleffective stress tensor strain energy density energy release ratecohesive zone裂纹扩展速率稳定裂纹扩展定常裂纹扩展亚临界裂纹扩展裂纹［扩展］减速止裂止裂韧度断裂类型滑开型张开型撕开型复合型撕裂撕裂模量断裂准则 J 积分 J 阻力曲线断裂韧度应力强度因子HRR 场守恒积分有效应力张量应变能密度能量释放率塑性区plastic zone张拉区stretched zone热影响区heat affected zone, HAZ延脆转变温度brittle-ductile transitiontempe- rature剪切带shear band 剪切唇shear lip无损检测non-destructive inspection双边缺口试件double edge notchedspecimen, DEN specimen 单边缺口试件single edge notchedspecimen, SEN specimen 三点弯曲试件three point bendingspecimen, TPB specimen 中心裂纹拉伸试件center cracked tensionspecimen, CCT specimen 中心裂纹板试件center cracked panelspecimen, CCP specimen 紧凑拉伸试件compact tension specimen,CT specimen 大范围屈服large scale yielding 小范围攻屈服small scale yielding 韦布尔分布Weibull distribution 帕里斯公式paris formula空穴化Cavitation应力腐蚀stress corrosion概率风险判定probabilistic riskassessment, PRAdamage mechanicsDamagecontinuum damage mechanics microscopic damage mechanicsaccumulated damage brittle damage ductile damage macroscopic damage microscopic damage microscopic damagedamage criteriondamage evolution equationdamage softeningdamage strengtheningdamage tensor damage threshold damage variable damage vector damage zone Fatigue low cycle fatigue stress fatigue random fatigue creep fatigue corrosion fatigue fatigue damage 损伤力学损伤连续介质损伤力学细观损伤力学累积损伤脆性损伤延性损伤宏观损伤细观损伤微观损伤损伤准则损伤演化方程损伤软化损伤强化损伤张量损伤阈值损伤变量损伤矢量损伤区疲劳低周疲劳应力疲劳随机疲劳蠕变疲劳腐蚀疲劳fatigue failure fatigue fracture fatigue crack fatigue life fatigue rupture fatigue strength fatigue striations fatigue threshold alternating load alternating stress stress amplitudestrain fatiguestress cyclestress ratio safe life overloading effect cyclic hardening cyclic softening environmental effectcrack gage crack growth, crackPropagation crack initiationcycle ratio experimental stressAnalysisactive[strain] gage疲劳失效疲劳断裂疲劳裂纹疲劳寿命疲劳破坏疲劳强度疲劳辉纹疲劳阈值交变载荷交变应力应力幅值应变疲劳应力循环应力比安全寿命过载效应循环硬化循环软化环境效应裂纹片裂纹扩展裂纹萌生循环比工作［应变］片backing material stress gage zero shift, zero drift strain measurementstrain gage strain indicator strain rosette strain sensitivity mechanical strain gage rectangular rosetteExtensometertelemetering of strain transverse gage factor transverse sensitivity weldable strain gage balanced bridge bonded strain gage bonded foiled gage bonded wire gage bridge balancing capacitance strain gage compensation technique compensation techniquereference bridge resistance strain gageself-temperature compensating gage基底材料应力计零［点］飘移应变测量应变计应变指示器应变花应变灵敏度机械式应变仪直角应变花弓I 伸仪应变遥测横向灵敏系数横向灵敏度焊接式应变计平衡电桥粘贴式应变计粘贴箔式应变计粘贴丝式应变计桥路平衡电容应变计补偿片补偿技术基准电桥电阻应变计semiconductor strainGageslip ring strain amplifier fatigue life gage inductance [strain] gagePhotomechanics Photoelasticity Photoplasticity Young fringe birefrigent effect contour of equal Displacement dark fringefringe multiplication interference fringeIsochromatic Isoclinic isopachic stress- optic lawIsostatic light fringe optical path differencephoto-thermo -elasticityphotoelastic coatingMethodphotoelastic sandwich半导体应变计集流器应变放大镜疲劳寿命计电感应变计光［测］力学光弹性光塑性杨氏条纹双折射效应等位移线暗条纹条纹倍增干涉条纹等差线等倾线等和线应力光学定律主应力迹线亮条纹光程差热光弹性光弹性贴片法Methoddynamic photo-elasticityspatial filtering spatial frequencyPolarizerreflection polariscope residual birefringentEffectstrain fringe valuestrain-optic sensitivitystress freezing effectstress fringe valuestress-optic pattern temporary birefringentEffect pulsed holographytransmission polariscope real-time holographic interfero - metrygrid methodholo-photoelasticityHologram Holographholographic interferometry holographic moire techniqueHolography whole-field analysis动态光弹性空间滤波空间频率起偏镜反射式光弹性仪残余双折射效应应变条纹值应变光学灵敏度应力冻结效应应力条纹值应力光图暂时双折射效应脉冲全息法透射式光弹性仪实时全息干涉法网格法全息光弹性法全息图全息照相全息干涉法全息云纹法全息术散斑干涉法speckle interferometry 散斑Speckle错位散斑干涉法speckle-shearinginterferometry,shearography散斑图Specklegram 白光散斑法white-light speckle method 云纹干涉法moire interferometry ［叠栅］云纹moire fringe［叠栅］云纹法moire method 云纹图moire pattern离面云纹法off-plane moire method 参考栅reference grating试件栅specimen grating分析栅analyzer grating面内云纹法in-plane moire method脆性涂层法brittle-coating method 条带法strip coating method坐标变换transformation ofCoordinates计算结构力学computational structuralmecha-nics加权残量法weighted residual method 有限差分法finite difference method 有限［单］元法finite element method 配点法point collocation里茨法Ritz method广义变分原理generalized variationalPrinciple 最小二乘法least square method胡［海昌］一鹫津原理Hu-Washizu principle赫林格-赖斯纳原理Hellinger-ReissnerPrinciple修正变分原理modified variationalPrinciple约束变分原理constrained variationalPrinciple混合法mixed method杂交法hybrid method边界解法boundary solution method有限条法finite strip method半解析法semi-analytical method协调兀conforming element非协调兀non-conforming element混合元mixed element杂交元hybrid element边界元boundary element强迫边界条件forced boundary condition自然边界条件natural boundary condition离散化Discretization离散系统discrete system连续问题continuous problem广义位移generalized displacement广义载荷generalized load广义应变generalized straingeneralized stress interface variable node, nodal pointElement corner node mid-side node internal node nodeless variablebar element truss element beam elementtwo-dimensional elementone-dimensional elementthree-dimensional element axisymmetric elementplate element shell elementthick plate element triangular element quadrilateral element tetrahedral element curved element quadratic element linear element cubic element quartic element isoparametric element广义应力界面变量节点［单］元角节点边节点内节点无节点变量杆元桁架杆元梁元二维元一维元三维元轴对称元厚板元三角形元四边形元四面体元曲线元二次元线性元三次元四次元等参［数］super-parametric element sub-parametric element variable-number-nodeelement Lagrange element Lagrange family serendipity element serendipity family infinite element element analysis element characteristicsstiffness matrixgeometric matrixequivalent nodal forcenodal displacementnodal load displacement vectorload vector mass matrix lumped mass matrix consistent mass matrixdamping matrix Rayleigh damping assembly of stiffnessMatricesconsistent mass matrix assembly of mass matrices assembly of elements超参数元亚参数元节点数可变元拉格朗日元拉格朗日族巧凑边点元巧凑边点族无限元单元分析单元特性刚度矩阵几何矩阵等效节点力节点位移节点载荷位移矢量载荷矢量质量矩阵集总质量矩阵相容质量矩阵阻尼矩阵瑞利阻尼刚度矩阵的组集载荷矢量的组集质量矩阵的组集local coordinate systemlocal coordinate area coordinates volume coordinates curvilinear coordinates static condensation contragradienttransformation shape function trial function test function weight function spline function substitute function reduced integration zero-energy mode p-convergenceh-convergenceblended interpolation isoparametric mapping bilinear interpolationpatch test incompatible modenode number element number band width banded matrix profile matrix局部坐标系局部坐标面积坐标体积坐标曲线坐标静凝聚合同变换形状函数试探函数检验函数权函数样条函数代用函数降阶积分零能模式P 收敛H 收敛掺混插值等参数映射双线性插值小块检验非协调模式节点号 M 二口. 单兀号minimization of band widthfrontal method subspace iteration method determinant search methodstep-by-step methodNewmark Wilsonquasi-Newton method Newton-Raphson method incremental method initial straininitial stresstangent stiffness matrixsecant stiffness matrix mode superposition method equilibrium iterationSubstructure substructure techniquesuper-element mesh generationstructural analysis programpre-processing post-processing mesh refinement stress smoothing composite structure带宽最小化波前法子空间迭代法行列式搜索法逐步法纽马克法威尔逊法拟牛顿法牛顿-拉弗森法增量法初应变初应力切线刚度矩阵割线刚度矩阵模态叠加法平衡迭代子结构子结构法超单元网格生成结构分析程序前处理后处理网格细化应力光顺。

材料学专业词汇

材料学专业词汇第一篇：材料学专业词汇8.Fracture :Microscopic Aspects fracturen 断裂microscopic a 微观的 macroscopic a 宏观的 crackn 裂纹nucleationn 形核 propagationn 扩展 ductilea 韧性的 brittlea 脆性的 brittlenessn 脆性 semi-brittle a 半脆性的 failure n 失效coalescence n 连接void n 空洞cross-sectional 横截面的 shear v 剪切transgranular a 穿晶的 preferentially adv 优先地 intergranular a 沿晶的 magnification n 放大 indentationn 凹陷8.1morphology n 组织，形态 dimple v 生微涡 rupturen 断裂 neckingn 颈缩 elastica 弹性的 ceramicsn 陶瓷 polymern 聚合物 tipn 尖端cleavage fracture 解理断裂 grain boundary晶界crystallographic plane 晶体学面 grainn 晶粒 crazen 微裂纹 tensilea 拉伸的stress concentration 应力集中 precursor n 预兆shearing banding 剪切带 flow stress流变应力 composite n 复合材料 fibrous a 纤维的 matrix n 基体 reinforcementn增强 bondingn 结合 compressionn 压缩 kinkingn 扭断 mechanismn 机制 plastica 塑性的 microbucklingn 微观弯曲8.2mobile dislocation可动位错 interatomic a 原子间的 bondn 键cohesive stress内聚应力 perfect crystal完整晶体Young’s modulus杨氏模量 defectn 缺陷 whiskern 晶须immobilea 不可动的 slip plane滑移面 restrictionn 限制 criterionn 判据 fibern 纤维 rollv 轧制heterogeneity n 不均匀性 striationn 擦痕 interiorn 内部 air bubble气泡 parametern 参数 inflexibilityn 不变性 dimplen 韧窝 triaxiala 三轴的 equiaxiala 等轴的 ellipticala 椭圆的 elastic-plastic弹塑性 qualitativea 定性的 stainless steel不锈钢interfacial bonding 界面结合 triaxialityn 三轴，cleavagev 解理，分裂 crystallographica.结晶学的 crystallinen 晶体orientationn.取向，排列方向facetn 倒角 screw dislocation螺旋位错cleavage step解理台阶 convergencen 会聚face-centered cubic面心立方体 body-centered cubic体心立方体 hexagonal close-packed 密排六方体 tungsten n钨molybdenumn 钼 chromiumn 铬 berylliumn 铍 magnesium n 镁 quenchv 淬火 tempern 回火 annealingn 退火 crystal lattice 结晶点阵 sensitizeda 激活 trajectoryn 轨迹 phosphorusn 磷.Recovery and Recrystallization recovery n 回复recrystallizationn 再结晶 transformationn 转变 ,相变 alloy n 合金meltinga 熔化的cold-workeda冷加工的 terminal a 终点的 curvature n 曲线Gibbs free energy 吉布斯自由能 entropyn 熵10.1 stored energy储存能 subgrainn 亚晶 impurityn 杂质 extrusion n 挤压 thermala 热的inversely proportion 反比例10.2relaxation process驰豫过程 vacancyn 空位interstitial atom 间隙原子 vacancy motion空位移动 hardnessn 硬度 resistivityn 电阻率 point-defect点缺陷self-explanatory a 不解自明的 elastic strain 弹性应变 stacking faults堆垛层错 lattice defect点阵缺陷 dislocation tangle 位错缠结 cellular a 多孔的misorienteda 取向错误的 two-dimensional二维的 diffusionn 扩散 Laue pattern劳厄斑 diffraction spot衍射斑点 etch-pit technique 点蚀坑技术10.3vacancy migration空位迁移 self-diffusion自扩散 dislocation climb位错攀移10.4statisticala统计的 fluctuationn波动 bulgev凸出来radiiradius pl 半径 sphericala球的, 球形的 protrudev（使）突出/伸出 incubationn孕育期velocityn速度、速率 coincident同时发生的 subboundary亚晶界10.5nucleation rate形核率 isothermallyad 等温地 impingevi 撞击 linear portion线形分配 nucleusn 核 phantomn模型integratev 求…的积分 negligiblea可以忽略的 modificationn修正 sigmoida反曲的 decayv衰退 metallographica金属结构的 potentialn电势、电位 molen摩尔 volumen体积 coefficientn系数 criticala临界的10.6dashed curve点划线inverse relationship 反函数关系 brass n黄铜fine-graineda细晶的 optimizev优化10.7 rodn 棒 soft solder软焊剂 bendv 弯曲deformation texture 形变织构 annealing texture :退火织构recrystallization texture 再结晶织构 cube texture 立方织构 mismatchv 错配 meritn 优点anisotropyn 各向异性 magnetica 有磁性的 sheetn 薄板secondary recrystallization 二次再结晶bracket n方括弧的一边 intersectionn 交叉点，交点 grooven 沟槽 retardv 阻止 diametern 直径 concavea 凹的 steady-state 稳态的fascinatinga 吸引人的 tungstenn 钨 filamentn 灯丝 thorian 二氧化钍 creepv 蠕变 resistancen 阻力 undopeda 无搀杂的 sketchn 略图 interlockv 连接 dopev 掺入 dopantn 搀杂物 sinteringn 烧结物volatilizev（使）挥发 ingotn 铸锭fiber texture纤维织构 submicroscopic a 亚显微的 poren 气孔Chapter 14 Some Applications of Physical Metallurgy metallurgyn 冶金学 manipulatev 操作 optimizea 最佳化 weld jointn 焊点 solder jointn 焊接点 devicen 仪器14.1strengthening mechanism 强化机制 work hardening 加工硬化solid solution hardening 固溶硬化 particle hardening粒子硬化 burgers vector 柏氏矢量 virtuallyad 实际上 reciprocal倒易的 flow stress流动应力 foreign atom异类原子 misfitn 错配 interstiticala 间隙的 symmetricala 对称的octahedral void八面体空位 unsymmetrica不对称的 tetragonala正方形的 screw n螺钉dilatational a膨胀的 distortion n扭转，畸变 etch v侵蚀dilute hydrofluoric acid 稀释氢氟酸膜14.2nitrogen n氮 revealv 揭示 amorphous a非晶的gaugen标距 bulkn整体Charpy impact test 摆锤式冲击试验 torchn焊灯horizontala水平的synonymous a同义的cast iron 铸铁flake n薄片nodular a球状的 graphite n石墨 quote v引用homogenization n均匀性 corrosionn腐蚀 weldability n焊接性 formabilityn成形性 machinability n可加工性 reliability n可靠性 whisker 金属晶须pearlitic a珠光体的ultimate a基本的patent n专利lamellar a层状的 cellular a多孔的substructuren亚结构 latch n板条substitutional a代位的solid-solution hardening 固溶硬化octahedral a八面体的interstitial void 间隙空位 dipolar a两极的precipitation hardening 析出硬化sub zero 零度以下的negligible a可忽略的 millisecond n毫秒autotempering 自动回火structure hardening 结构硬化lath martensite 板条马氏体dislocation hardening 位错强化plate martensite 片状马氏体 residual a 残余的microcracking n显微裂变 substantially a实质上 redistribution n再分配spontaneous cracking 自发破裂 spheroidize v球化eutectoid temperature 共析温度Ostwald ripening process 奥斯特瓦尔德熟化过程Bainite n贝氏体retained austenite 残余奥氏体 regainn回伸率age-hardening 时效硬化vanadium n钒molybdenum n钼detrimental a有害的 retard v 延迟overaging n过时效 cohesion n内聚力ausformed steel 奥氏体钢 martensitic steel 马氏体钢high-hardenability 高硬化能力i inherited dislocation 遗传的位错 subsequently adv后续的 refinement n 细化 twinned a形成孪晶的 equivalent a相等的stress-true strain diagram 应力－应变曲线neck down 颈缩断开maraging steel 马氏体时效钢decomposition[化学]分解iron-nickel phase diagram 铁-镍相图binary a 二元的equilibrium n平衡 hysteresis n 迟滞现象heat-treat cycle 热处理循环ageing reaction 时效反应angstromn埃 deoxidatonn 脱氧 v-notchv 型缺口 siliconn硅postulatev视……为当然decarburization v脱去……的碳 preheating n预热 post-weld 焊接之后magnetic property 磁性性能 slant v（使）倾斜superconductor n超导体第二篇：专业词汇企业风险管理员相关概念一、企业全面风险管理的概念：企业全面风险管理是指企业在实现未来战略目标的过程中，试图将各类不确定因素产生的结果控制在预期可接受范围内的方法和过程，以确保和促进组织的整体利益实现。

腐蚀与防护术语中、英文名词对照

1、加速腐蚀试验accelerated corriosion test2、加速氧化accelerated oxidation3、酸洗acid cleaning4、酸洗清洁剂acid picking5、酸洗清洁剂acidic cleaner6、酸度acidity7、活化activity8、激化能activation energy9、活化极化activation polarization10、活化剂activator11、活性的，活化的active12、活化金属active metals13、活化-钝化电池active-passive cell14、活性区，活化区active zone15、活度activity16、优级海军黄铜admiralty brass17、充气aeration18、充气电池aeration cell19、嗜氧菌aerobic bacteria20、老化aging21、老化作用aging action22、大气污染air pollution23、周浸试验alternate immersion test24、厌氧菌anaerobic bacteria25、厌氧菌腐蚀anaerobic corrosion26、阴离子anion27、阳极anode28、阳极极化anodic polarization29、阳极电流密度anodic current density30、阳极氧化物膜anodic oxide coating31、阳极保护anodic protection32、阳极区电解质anolyte33、耐侯性低合金钢anti-weathering low alloy steel34、外加电位applied potential35、水溶液腐蚀aqueous corrosion36、人造海水artificial seawater37、大气暴露试验atmospheric exposure test38、大气腐蚀atmospheric corrosion39、奥氏体不锈钢austenitic stainless steel40、辅助电极auxiliary electrode41、细菌腐蚀bacteria corrosion42、贱金属base metal43、双金属腐蚀bimetallic corrosion44、甘汞电极calomel electrode45、甘汞电极电位calomel electrode potential46、碳化carburizing47、阴极cathode48、阴极保护cathodic protection49、阴极极化cathodic polarization50、阴极电流密度cathodic current density51、阴极电流效率cathodic current efficiency52、阴极区电解质catholyte53、阳离子cation54、碱脆caustic embrittlement55、空泡作用cavitation56、空泡腐蚀cavitation corrosion57、空泡损伤cavitation damage58、空泡磨蚀cavitation erosion59、电池cell60、渗镀，渗碳cementation61、化学清洗chemical cleaning62、化学转化涂层chemical conversion coating63、化学钝化chemical passivation64、化学镀chemical〔electroless〕plating65、铬酸盐处理〔铬化〕chromating66、清洗液cleaning solution67、浓差电池concentration cell68、接触腐蚀contact corrosion69、转换涂层conversion coating70、恒变形constant deflection71、恒载荷constant load72、腐蚀corrosion73、腐蚀-磨蚀corrosion-erosion74、腐蚀疲劳corrosion fatigue75、腐蚀电位corrosion potential76、腐蚀控制corrosion control77、腐蚀电流corrosion current78、腐蚀电流密度corrosion current density79、腐蚀疲劳开裂corrosion fatigue cracking80、腐蚀疲劳极限corrosion fatigue limit81、腐蚀产物corrosion product82、腐蚀速率corrosion rate83、腐蚀科学corrosion science84、腐蚀试验corrosion test85、腐蚀失重corrosion weight loss86、腐蚀增重corrosion weight gain87、电偶couple88、电偶作用couple action89、开裂cracking90、龟裂crazing91、缝隙腐蚀crevice corrosion92、临界阳极电流密度critical anodic current density93、临界浓度critical concentration94、临界湿度critical humidity95、晶体crystal96、辅助电极counter electrode97、电流密度current density98、去活化作用deactivation99、脱合金元素作用dealloying100、脱铝dealuminization101、去气deaeration102、缺陷defect103、脱脂degreasing104、去矿化物质demineralization105、去极化depolarization106、腐蚀深度depth of corrosion107、沉积物腐蚀deposit corrosion108、脱锌dezincification109、扩散diffusion110、扩散电位diffusion potential111、差异充气电池differential aeration cell112、极限扩散电流密度diffusion limited current density 113、电流electric current114、电位electric potential115、电化学电池electrochemical cell116、电化学腐蚀electrochemical corrosion117、电化学当量electrochemical equivalent118、电极electrode119、电极电位electrode potential120、电极反应electrode reaction121、电解质electrolyte122、电解electrolysis123、电解清洗electrolytic cleaning124、电动序electromotive force〔Emf〕series125、负电性电位electropositive potential126、电泳沉积electrophoretic deposition127、电镀electroplating128、正电性电位electropositive potential129、静电喷涂层electrostatic coating130、脆化embrittlement131、磨耗erosion132、磨耗腐蚀〔或冲击腐蚀〕erosion-corrosion133、平衡电位equilibrium potential134、腐蚀极化图Evans diagram135、剥蚀exfoliation corrosion136、交换电流密度exchange current density 137、暴露实验exposure test138、疲劳fatigue139、铁素体ferrite140、铁素体不锈钢ferrite stainless steel 141、丝状腐蚀filiform corrosion142、弗拉德电位Flade potential143、剥层腐蚀foliation144、膜film145、微动腐蚀fretting corrosion146、燃灰腐蚀fuel ash corrosion147、电偶作用galvanic action148、伽法尼电池galvanic cell149、电偶腐蚀galvanic corrosion150、电偶对galvanic couple151、电偶序galvanic series152、热镀锌galvanizing153、恒电流的galvanoststatic154、普遍〔全面〕腐蚀general corrosion 155、晶界裂纹grain boundary crack156、晶粒grain157、石墨化腐蚀graphitic corrosion158、重量法gravimetric methods159、绿锈green rot160、哈氏合金hastelloy161、热影响区heat affected zone〔HAZ〕162、耐热钢heat resistant steel163、热处理heat treatment164、高温腐蚀high temperature corrosion 165、热腐蚀hot corrosion166、热镀铝hot-dip alumizing167、湿度humidity168、氢腐蚀hydrogen attack169、氢鼓泡hydrogen blistering170、氢损伤hydrogen damage171、氢电极hydrogen electrode172、氢脆hydrogen embrittlement173、氢致开裂hydrogen induced cracking 174、氢超电压hydrogen overvoltage175、氢标hydrogen scale176、浸泡实验immersion test177、冲蚀impingement corrosion178、因科乃尔Inconel179、因科罗Incoloy180、工业大气industrial atmosphere181、缓蚀剂inhibitor182、晶间裂纹intergranular crack183、不溶性阳极insoluble anode184、晶间腐蚀intergranular corrosion185、延晶应力腐蚀断裂intergranular stress corrosion cracking 186、内氧化interal oxidation187、内应力interal stress188、例子浓差电池ion concentration cell189、离子ion190、离子注入ion implantation191、刀线腐蚀knife-line corrosion192、激光釉化laser glazing193、层状腐蚀layer corrosion194、晶格缺陷lattic defect195、液态金属腐蚀liquid metal corrosion196、局部作用local action197、局部电池local cell198、局部腐蚀local corrosion199、海洋腐蚀marine corrosion200、马氏体martensite201、马氏体不锈钢martensitic stainless steel202、力学性能mechanical property203、金属离子浓差电池metal ion concentration cell204、金属喷镀metal spray205、金属镀层metallic coating206、微生物腐蚀microbiological corrosion207、金属粉化metal dusting208、混合电位mixed potential209、轧制铁鳞mill scale210、贵金属noble metal211、海军黄铜navy brass212、贵电位noble potential213、非金属涂层nonmetallic coating214、氮化nitriding215、过电位overpotential216、氧化oxidation217、开路电位open circuit potential218、氧化-复原电位oxidation-reduction potential219、氧化物oxide220、氧化膜oxide film221、氧浓差电池oxygen concentration cell222、钝化passivation223、钝化剂passivator224、钝化-活化电池passive-active cell225、钝化的，钝性的passive226、铜绿patina227、酸度计pH indicator，acidometer228、磷酸盐处理phosphating229、酸洗液pickling solution230、蚀孔pit231、点蚀pitting232、点蚀击穿电位pitting breakdown potential233、点蚀系数pitting factor234、点蚀电位pitting potential235、极化polarization236、动电位potential dynamic〔potentiokinetic〕237、恒电位仪potentiostat238、恒电位potentisostic239、电位-pH图Pourbaix diagram，potential-pH diagram 240、底涂层prime coat241、保护电位protective potential242、氧化-复原电位redox potential243、复原reduction244、参比电极reference electrode245、相对湿度relative humidity246、残余内应力residua interal stress247、铁锈rust248、防锈油rust preventive oil249、牺牲阳极保护sacrifice anode protection250、盐水喷雾试验salt spray test251、喷砂sand blasting252、饱和甘汞电极saturated calomel electrode〔SCE〕253、氧化皮scale254、季裂season cracking255、选择性腐蚀selective corrosion256、选择性氧化selective oxidation257、自钝化self passivation258、敏化热处理sensitizing heat treatment259、喷丸shot peening260、银-氯化银电极silver-sliver chloride electrode 261、慢应变速率slow strain rate262、土壤腐蚀soil corrosion263、剥离spalling264、不锈钢stainless steel265、标准电极电位standard electrode potential266、标准氢电极standard hydrogen electrode267、应变能strain energy268、杂散电流腐蚀stray current corrosion269、应力场强度因子stress intensity factor270、应力腐蚀断裂stress corrosion cracking〔SCC〕271、硫化sulfidation272、外表氧化surface oxidation273、外表处理surface treatment274、皮下腐蚀subsurface corrosion275、塔菲尔斜率Tafel slope276、失泽tarnish277、抗拉强度tensile strength278、热偶腐蚀thermogalvanic corrosion279、热力学thermodynamics280、结瘤腐蚀tuberculation281、穿晶腐蚀transgranular corrosion282、穿晶应力腐蚀断裂transgranular stress corrosion cracking 283、过钝化transpassive284、膜下腐蚀underfilm corrosion285、均匀腐蚀umiform corrosion286、水线腐蚀waterline corrosion287、焊接腐蚀weld decay288、湿度humidity289、工作电极working electrode290、291、292、。

Effect of welding on the stress corrosion cracking behaviour of prior cold worked AISI 316L

Effect of welding on the stress corrosion cracking behaviour of prior cold worked AISI 316L stainless steel studied by using the slow strain rate testPilar De Tiedra,Óscar Martín ⇑Departamento CMeIM/EGI/ICGF/IM/IPF,Universidad de Valladolid,Escuela de Ingenierías Industriales,Paseo del Cauce 59,Valladolid 47011,Spaina r t i c l e i n f o Article history:Received 27December 2012Accepted 4February 2013Available online 16February 2013Keywords:Austenitic stainless steel Prior cold workSlow strain rate test Weldinga b s t r a c tThis work aims to assess the effect of welding on the stress corrosion cracking (SCC)behaviour of prior cold worked AISI 316L stainless steel from ultimate tensile strength (UTS)and time to failure (TF)obtained in slow strain rate tests (SSRTs),which are conducted in corrosive environment and in non-cor-rosive environment (air).The UTS of cold worked and welded specimens does not show signiﬁcant vari-ations with prior cold work (CW).However,the TF of cold worked and welded specimens depends on several phenomena that occur in the heat affected zone (HAZ),such as sensitization,recrystallization,recrystallized grain growth or thermal transformation of strain-induced martensite.Additionally,a metallographic study of SSRT tested specimens is performed with the aim of assessing the fracture mode,which proves to be ductile.This work shows that the combined effect of prior CW and welding does not give rise to SCC because the degree of sensitization (DOS)induced in the HAZ is not sufﬁcient to direct the crack growth.Ó2013Elsevier Ltd.All rights reserved.1.IntroductionAustenitic stainless steels (SSs),due to their good combination of mechanical properties,corrosion resistance and weldability [1–3],are extensively used in a wide variety of industries,among which the power generation industry is included [4,5].Stress cor-rosion cracking (SCC)is a failure mechanism to which austenitic SS are subjected [6]and,since it can lead to catastrophic failures of structural components [7],it is one of the most severe mainte-nance problems in the power generation industry [8].The effects of cold work (CW)[9–11]and the effects of welding process [12]on SCC of austenitic SS have been widely studied and,since there are many systems in the power generation industry,such as the Boiling Water Reactor (BWR)piping systems [13],which are constructed by a deformation process followed by a welding process,the knowledge of the effect of prior CW on the SCC behaviour of welded joints of austenitic SS is of growing inter-est [10,13].One of the most common problems encountered in austenitic SS weldments is associated with sensitization in the heat affected zone (HAZ)that leads to intergranular corrosion and transgranular corrosion [14,15].Since sensitized zones may present an easy crack propagation path and facilitate SCC [16],the HAZ has a high SCC susceptibility [13].The effect of prior CW on the HAZ microstructure is highly com-plex because the combined effect of mechanical energy,resulting from prior CW,and thermal energy,resulting from welding pro-cess,gives rise to microstructural heterogeneity in the HAZ,where three subzones can be found [17]:(i)recrystallized grain growth subzone (the closest to weld metal (WM));(ii)recrystallized grain subzone;(iii)subzone where recrystallization does not occur but where the signs of prior CW have partially disappeared (the most distant from WM).Since grain size has inﬂuence on the degree of sensitization (DOS),which decreases with decreasing grain size [17],and since a sufﬁciently high prior CW may change the localized corrosion at-tack mode from intergranular to transgranular [18]and may give rise to strain-induced martensite,which enhances transgranular corrosion and a rapid desensitization kinetics [19,20],the prior CW has an important inﬂuence on the DOS induced by welding process.The slow strain rate test (SSRT)is widely used to assess the SCC susceptibility of austenitic SS,since it provides useful information about SCC susceptibility in any corrosive environment in a rela-tively short time span [21].The aim of this work is to assess the effect of welding on the SCC behaviour of prior cold worked AISI 316L stainless steel.2.Experimental procedure 2.1.MaterialsThe chemical composition of AISI 316L is shown in Table 1.The metallographic characterization of as-received material,which is0261-3069/$-see front matter Ó2013Elsevier Ltd.All rights reserved./10.1016/j.matdes.2013.02.009Corresponding author.Tel.:+34983423533;fax:+34983423389.E-mail address:oml@eii.uva.es (Ó.Martín).performed by using electrolytic etching with to ASTM:A 262-10Practice A,shows an signs of residual deformation caused by d -ferrite bands,whose presence is greater in proximity to the surface (Fig.1),clearly direction and slip bands in zones close to as-received material thickness is 4mm.2.2.SSRTsSSRTs are conducted on:(i)cold worked (ii)cold worked and non-welded specimens the aim of obtaining a reference for the cold specimens.2.2.1.CW levelsThe as-received material is deformed by CW levels considered are 0%,10%,20%and thicknesses are respectively 4mm,3.6mm,It is experimentally observed that the (40%)gives rise to strain-induced martensite 2.2.2.Welding procedureThe welded joints are performed by using inert gas (MIG)procedure,with argon as preparation,butt joint and AISI 308L type [23–25].Three welding zones are discriminated WM,HAZ and base material.2.2.3.SSRT specimensSSRT specimens are obtained from 10%,20%and 40%and from welded joints ously deformed to 0%,10%,20%and 40%perpendicular to the specimen axis and,for welded joint is located in the middle of (Fig.4).Therefore,there are eight different mens:4(four CW levels)Â2(with and ing process).The SSRT specimen ASTM:E8/E8M-11and to ASTM:G in Fig.5.2.2.4.SSRT performanceThe SSRTs are performed according to SSRTs are conducted using a tensile testing a strain rate of 1.67Â10–6s À1.Strain is someter of 50mm gauge length.The test corrosive environment,is 1N H 2SO 4+0.5N aggressive environment for AISI 316L character and the presence of chlorides,at sealed polytetraﬂuoroethylene (PTFE)cell.out under potentiostatic control using a stat.A Saturated Calomel Electrode (SCE)is used as a reference electrode and two graphite rods are used as counter electrodes.With the aim of selecting a test potential in the range of active–passive transition,which is a critical potential range for crack growth [10,26,27],the potentiodynamic anodic polarization curvesof the material deformed to 0%,10%,20%and 40%are obtained according to ASTM:G 5-94(2011)e1following an experimental procedure described in detail elsewhere [28];as it is shown in Fig.6,the selected test potential is À250mV SCE .Table 1Chemical composition of AISI 316L (wt.%).C Cr Ni Si Mn Mo Al Co 0.0317.1810.340.036 1.35 1.860.01930.17Cu Nb Ti V W P S Fe 0.230.010.02120.070.050.0310.003Bal.Micrograph of a longitudinal section of as-received AISI 316L.The presence -ferrite bands is greater inside the thickness than in proximity to the Electrolytic etching with oxalic acid.2.Micrograph of a longitudinal section of as-received AISI 316L obtained zone close to the surface.The presence of slip bands shows that the as-received material has residual deformation caused by forming process.Electrolytic etching with oxalic acid.104P.The gauge length is exposed to the test solution,while the other areas of the specimen are covered with PTFE tape.The solution is poured into the PTFE cell and deaerated with nitrogen gas for 1h before the test.The specimen is mounted in the PTFE cell and in the tensile machine and is kept unloaded until a constant corrosion potential is reached.Both tensile straining and application of the selected potential (À250mV SCE )are started simultaneously.The experiment continues until the specimen fractures completely.In addition to the SSRTs in corrosive environment,SSRTs in non-corrosive environment (air)are conducted at room temperature on the eight types of SSRT specimens previously described.UTS obtained from the SSRTAs it is shown in Fig.7,the UTS obtained from SSRTs conducted on cold worked and non-welded specimens increases with increas-ing CW level due to strain hardening.However,the UTS obtained from SSRTs conducted on cold worked and welded specimens does not show signiﬁcant variations with prior CW.Therefore,since the UTS of non-deformed (prior CW of 0%)and welded specimens and the UTS of non-deformed (CW of 0%)and non-welded specimens are similar,the differences between the UTS of welded specimens and the UTS of non-welded specimens increase with increasing CW level.The ratio of UTS obtained from SSRTs in corrosive environment (1N H 2SO 4+0.5N NaCl)to UTS obtained from SSRTs in non-corro-sive environment (air),UTS CE /UTS NCE ,shows that the UTS is not sensitive to the corrosive environment for any CW level (Fig.8);this fact may be due to the low DOS induced in the HAZ of the 3.Micrograph of AISI 316L with a deformation level of 40%without subsequent welding process.The microstructure shows strain-induced martensite.Etching with Kalling’s reagent [22].specimen obtained from material deformed to 10%and subjected to a subsequent welding process.The arrows speciﬁes the SSRT specimen dimensions.The thickness of the SSRT specimen depends on the CW level and is 4mm for for a CW level of 20%and 2.4mm for a CW level of 40%.Selection of test potential in the range of active–passive transition from potentiodynamic anodic polarization curves of the material deformed to:(A)(C)40%;(D)10%.increasing CW level,as a consequence of the decrease of ductility due to strain hardening,whereas the behaviour of the cold worked and welded specimens is more complex because the combined ef-fect of mechanical energy,resulting from prior CW,and thermal With the aim of assessing the effect of prior CW on the DOS the HAZ,an electrochemical potentiokinetic reactivation (EPR)test carried out [33],before the SSRT,for each of the four cold worked and welded specimens.The EPR tests are performed,according ASTM:G 108-94(2010)following an experimental procedure de-scribed in detail elsewhere [34],on the HAZ of each specimen using a large-scale electrochemical cell [14,18]and a lacquer coat-to protect the untested area [35,36].The EPR curves obtainedFig.7.UTS obtained from SSRTs conducted on:(i)non-welded specimens (NWSs)with CW in non-corrosive environment (NCE);(ii)NWS with CW in corrosive environment (CE);(iii)welded specimens (WSs)with prior CW in NCE;(iv)WS with prior CW in CE.Fig.8.Ratio of UTS obtained from SSRTs in corrosive environment (CE)to UTS obtained from SSRTs in non-corrosive environment (NCE),UTS CE /UTS NCE .SSRTs are conducted on:(i)non-welded specimens (NWS);(ii)welded specimens (WS).Fig.9.TF obtained from SSRTs conducted on:(i)non-welded specimens (NWSs)with CW in non-corrosive environment (NCE);(ii)NWS with CW in corrosive environment (CE);(iii)welded specimens (WSs)with prior CW in NCE;(iv)WS with prior CW in CE.10.Micrograph of recrystallized grain growth subzone of the HAZ,adjacent WM,obtained before SSRT.Prior CW of 0%with subsequent welding process.Electrolytic etching with oxalic acid.11.Micrograph of recrystallized grain growth subzone of the HAZ,adjacent WM,obtained before SSRT.Prior CW of 10%with subsequent welding process.grain size is larger than that shown in Fig.10.Electrolytic etching with oxalic acid.from the cold worked and welded specimens(Fig.14)show that the DOS of the HAZ of welded specimens with prior CW levels 10%and20%is higher than that of HAZ of welded specimens with prior CW levels of0%and40%.This result is consistent with the fact that the DOS increases with increasing prior CW until a certain prior CW level is reached and then decreases due to the change the localized corrosion attack mode from intergranular(Figs.and11)to transgranular(Figs.12and13)[18]and due to the presence of strain-induced martensite in the material deformed 40%before being subjected to welding process(Fig.3);this12.Micrograph of recrystallized grain growth subzone of the HAZ,adjacent WM,obtained before SSRT.Prior CW of20%with subsequent welding process. grain size is larger than that shown in Fig.11.Electrolytic etching with oxalic acid.13.Micrograph of recrystallized grain growth subzone of the HAZ,adjacent WM,obtained before SSRT.Prior CW of40%with subsequent welding process which gives to thermal transformation of strain-induced martensite.The grain smaller than that shown in Fig.12.Electrolytic etching with oxalic acid.14.EPR curves obtained,before the SSRT,from the HAZ of welded specimensprior CW level of:(A)0%;(B)40%;(C)10%;(D)20%.Fig.15.Ratio of TF obtained from SSRTs in corrosive environment(CE)to obtained from SSRTs in non-corrosive environment(NCE),TF CE/TF NCE.SSRTs are conducted on:(i)non-welded specimens(NWS);(ii)welded specimens(WS).16.Macrograph of the fracture zone in the cold worked to40%and welded specimen obtained after SSRT in corrosive environment.Theﬁgure shows macro-scopic evidence of plastic deformation.17.Micrograph of the fracture zone in the cold worked to10%and welded specimen obtained after SSRT in corrosive environment.Theﬁgure shows micro-scopic evidences of plastic deformation,such as deformed d-ferrite bands and bands(SB),in the HAZ.strain-induced martensite also enhances transgranular corrosion and a rapid desensitization kinetics[19,20].The double loop elec-trochemical potentiokinetic reactivation(DLEPR)test may be per-formed under the same conditions and with the same aim that the EPR test[37–39]but previous studies shows that sensitivity of EPR is greater than that of DLEPR at low DOS[14,34]and,hence,the EPR is chosen instead of DLEPR.The ratio of TF obtained from SSRTs in corrosive environment (1N H2SO4+0.5N NaCl)to TF obtained from SSRTs in non-corro-sive environment(air),TF CE/TF NCE,shows that the TF is more sen-sitive to the corrosive environment than the UTS(Figs.8and15). Furthermore,the ratio TF CE/TF NCE shows that,for welded speci-mens,the inﬂuence of the corrosive environment is more signiﬁ-cant for prior CW levels of10%and20%,in which the DOS of the HAZ is higher(Figs.14and15).3.3.Metallographic studyThe cold worked and welded specimens tested by SSRT in cor-rosive environment show ductile fracture mode with macroscopic (Fig.16)and microscopic(Fig.17)evidence of plastic deformation, which is not characteristic of SCC fractures[27,40].4.ConclusionsFrom the present work,which aims to assess the effect of weld-ing on the SCC behaviour of prior cold worked AISI316L stainless steel,the following conclusions can be drawn:(1)The UTS of cold worked and non-welded SSRT specimensincreases with increasing CW level due to strain hardening.(2)The UTS of cold worked and welded SSRT specimens doesnot show signiﬁcant variations with prior CW.(3)The UTS is not sensitive to the corrosive environment for anyCW level.(4)The TF of cold worked and non-welded SSRT specimensdecreases with increasing CW level,as a consequence of the decrease of ductility due to strain hardening.(5)The TF of cold worked and welded SSRT specimens decreaseswith increasing prior CW level until a prior CW level of20% is reached and then increases.(6)The TF is more sensitive to the corrosive environment thanthe UTS.Furthermore,for welded specimens,the inﬂuence of the corrosive environment is more signiﬁcant for prior CW levels of10%and20%,in which the DOS of the HAZ is higher.(7)The combined effect of prior CW and welding does not giverise to SCC because the DOS induced in the HAZ is not sufﬁ-cient to direct the crack growth.References[1]Özyürek D.An effect of weld current and weld atmosphere on the resistancespot weldability of304L austenitic stainless steel.Mater Design 2008;29:597–603.[2]Martín O,De Tiedra P,López M,San-Juan M,García C,Martín F,et al.Qualityprediction of resistance spot welding joints of304austenitic stainless steel.Mater Design2009;30:68–77.[3]Silva 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Stress corrosion cracking of 2205 duplex stainless steel in H2S–CO2 environmen

Stress corrosion cracking of 2205duplex stainless steel in H 2S–CO 2environmentZ.Y.Liu ÆC.F.Dong ÆX.G.Li ÆQ.Zhi ÆY.F.ChengReceived:10December 2008/Accepted:25April 2009/Published online:14June 2009ÓSpringer Science+Business Media,LLC 2009Abstract Stress corrosion cracking (SCC)behavior of 2205duplex stainless steel (DSS)in H 2S–CO 2environment was investigated by electrochemical measurements,slow strain rate test (SSRT),and scanning electron microscopy (SEM)characterization.Results demonstrated that the passive current density of steel increases with the decrease of solution pH and the presence of CO 2.When solutions pH was 2.7,the steel SCC in the absence and presence of CO 2is expected to be a hydrogen-based process,i.e.,hydrogen-induced cracking (HIC)dominates the SCC of the steel.The presence of CO 2in solution does not affect the fracture mechanism.However,the SCC susceptibility is enhanced when the solution is saturated simultaneously with H 2S and CO 2.With elevation of solution pH to 4.5,the hydrogen evolution is inhibited,and dissolution is involved in cracking process.Even in the presence of CO 2,the additional cathodic reduction of H 2CO 3would enhance the anodic reaction rate.Therefore,in addition to the hydrogen effect,anodic dissolution plays an important role in SCC of duplex stainless steel at solution pH of 4.5.IntroductionSulﬁde stress corrosion cracking (SCC)has been identiﬁed as one of essential threats to the componential integrity inpetroleum and petrochemical industries [1–4].In recent years,the continuously increasing energy demands drive the exploration of deep,high H 2S-,and CO 2-containing oil and gas wells [5],where high strength steels and stainless steels are required to resist high stress and highly corrosive environment [6–12].The 2205duplex stainless steels (DSS)becomes a promising candidate material used in H 2S environment due to its excellent mechanical behavior and high corro-sion resistance.Extensive work has been conducted to investigate SCC behavior of 2205DSS under a variety of environmental conditions.For example,hydrogen embrittlement (HE)and SCC of duplex stainless steel was studied in either NACE TM-0177standard solution [13]or in simulated service conditions [4,14–17].Tsai and Chen [16]demonstrated that 2205DSS was immune to SCC in a concentrated NaCl solution up to 26wt%con-centration in a near neutral pH condition.However,2205DSS undergoes HE in hydrogen-charging conditions,such as cathodic polarization or in the presence of hydrogen sulﬁde [18].Furthermore,Luu et al.[19]and Owczarek et al.[20]reported that the ferritic phase in 2205DSS is more susceptible to HE and hydrogen-induced cracking (HIC)under hydrogen charging.El-Yazgi and Hardie [4]found that SCC of duplex and super-duplex stainless steels occurred in a wide temperature range in sour environment.To date,research has been focused on SCC of 2205DSS in H 2S-or CO 2-containing conditions.There has been limited work conducted under the environmental condition where the interaction of CO 2and H 2S plays an essential role in SCC of duplex stainless steel.Furthermore,a mechanistic effect of solution pH on SCC of DSS has remained unclear.Thus,this work is an expansion of some of previous research.Z.Y.Liu ÁC.F.Dong ÁX.G.Li (&)ÁQ.ZhiCorrosion and Protection Center,University of Science and Technology Beijing,Beijing 100083,China e-mail:lixiaogang99@Y.F.Cheng (&)Department of Mechanical &Manufacturing Engineering,University of Calgary,Calgary,AB T2N 1N4,Canada e-mail:fcheng@ucalgary.caJ Mater Sci (2009)44:4228–4234DOI 10.1007/s10853-009-3520-xIn this work,electrochemical measurement,slow strain rate test (SSRT),and surface analysis technique were combined to investigate the effects of pH,CO 2,and stress on SCC susceptibility of 2205DSS in H 2S-containing environment.The interaction of various affecting factors in SCC of DSS was analyzed.It is anticipated that this research provides an essential insight into the mechanism of SCC of DSS in H 2S-and CO 2-containing conditions as well as the role of solution pH in the steel SCC.Experimental procedureSpecimens used in this work were cut from a commercial cold-rolling 2205DSS plate,with the chemical composi-tion (wt%):C 0.029,Si 0.59,Mn 1.20,Cr 22.57,Ni 4.63,Mo 2.62,N 0.13,S 0.0043,P 0.029,and Fe balance.Electrodes for electrochemical measurements were ground to 600grit emery papers on all faces.The unexposed edges were coated with a masking paint to prevent crevice cor-rosion between the epoxy mount and the electrode.The specimens were embedded in epoxy resin manufactured by LECO leaving a working area of 1.0cm 2.The working surface was subsequently polished with 3and 1l m dia-mond pastes,cleaned by distilled water and methanol.The specimens for SSRT,made according to GB T15970speciﬁcation [21],were covered with LECO epoxy resin,leaving a working area of 2.4cm 2.The working surface of specimen was subsequently polished with 800and 1,000grit emery papers,cleaned by distilled water and acetone.A metallographic examination of 2205DSS showed that it contained a duplex ferritic–austenitic microstructure after chemically etching in solution of 20mL HCl,20mL H 2O,and 5g CuSO 4Á5H 2O,as seen in Fig.1.SSRT test was performed in air to obtain the mechanical properties of the steel:yield strength (r 0.2)506MPa,ultimate strength (r b )717MPa,elongation rate (d )40.5%,and reduction-in-area (W )67.9%.The basic test solution was NACE TM0177-1996solu-tion of 5%NaCl ?0.5%CH 3COOH ?saturated H 2S (pH =2.7),where the saturated H 2S concentration in the solution was about 3,200ppm.Three other solutions were prepared to investigate the effects of solution pH and CO 2concentration:5%NaCl ?0.5%CH 3COOH ?saturated H 2S (pH 4.5),5%NaCl ?0.5%CH 3COOH ?saturated H 2S ?saturated CO 2(pH 2.7),and 5%NaCl ?0.5%CH 3COOH ?saturated H 2S ?saturated CO 2(pH 4.5).A solution of 5%NaOH was used to adjust pH values of the test solutions.The saturated CO 2concentration in solution was approximately 5,000ppm.All solutions were deaer-ated with highly pure nitrogen gas (99.99%)prior to tests.Two loading methods were used to study SCC of stressed steel specimen.The ﬁrst one was to prepare a U-bent specimen,based on ASTM G30[22],to obtain a static stress,with the axial direction of the outer bent surface paralleling to the rolling direction.U-bent specimens were soaked in the test solutions for 720h,and then cleaned and examined by an optical microscopy and scanning electron microscopy (SEM).The second method was to use SSRT technique to create a dynamic tensile loading at a strain rate of 1910-6s -1.SSRTs were performed on a WDML-30KN Materials Test System.All tensile specimens were ground parallel to the tension direction to 800grit emery papers.The test was performed at corrosion potential and ambient temperature (about 20°C).Potentiodynamic polarization curve measurements were carried out through a 2273electrochemical system by a three-electrode cell,with an unstressed 2205DSS speci-men as working electrode,a saturated calomel electrode as reference electrode,and a platinum plate as counter elec-trode.Polarization range was from -500mV to 2,500mV (vs.corrosion potential)at a potential sweep rate of 1mV/s.The tests were conducted at room temperature (*22°C).Fracture surface of tensile specimens after SSRT and the corrosion morphology of working electrodes after electro-chemical tests were observed bySEM.Fig.1Microstructure of 2205duplex stainless steel.a Parallel to rolling plane and b normal to rolling planeResultsElectrochemical measurementsFigure2shows the polarization curves measured on2205 DSS electrode in solutions saturating with H2S.It is seen that passivity was achieved on steel in all solutions.While there was little change of corrosion potential in various solutions,as shown in Fig.2b in detail,the passive current density differs from each other remarkably.In general,an increase in solution pH decreased the passive current density,and purging CO2in solution increased the current density.Moreover,there was an active–passive transition range for curves measured at pH2.7with and without CO2. However,in solutions with pH4.5,the passive current density was relatively stable,without an apparent active–passive transition.U-bent specimen soaking testFor specimens soaked in solutions without CO2,there was no crack found on the outer surface the specimen,and the specimen remained shiny.However,for those soaked in pH 2.7and4.5solutions with CO2,although there was no crack observed,the surface of the specimen became gray and remained shiny,respectively.Figure3shows the SEM observation of the specimen soaked in pH2.7,H2S-satu-rated solution without and with CO2.It is seen that there was no corrosion sign on specimen soaked in CO2-free solution,while the specimen soaked in CO2-containing solution contained a number of transgranular micro-cracks that were transverse to the loading direction on the surface.SSRTsTypical stress–strain curves obtained by SSRT on2205 DSS specimen in various solutions are shown in Fig.4. Generally,there was a lower elongation-to-rupture in solutions with a lower pH than that in a higher pH solution. Furthermore,the presence of CO2in solution decreased elongation remarkably.Furthermore,the susceptibility of steel to SCC in dif-ferent solutions was determined by reduction-in-area factor (I W),as shown in Fig.5.I W was deﬁned as:I W¼1ÀW SW0Â100%;ð1Þwhere W S and W0were reduction-in-areas measured in solution and in air,respectively.It is seen from Fig.5that with the decrease of pH value,I W increased signiﬁcantly. Moreover,I W determined in CO2-containing solution was higher than that obtained in CO2-free solution at individual pH.Since I W was a ductility-loss parameter[6,7],it was apparent that the SCC susceptibility of2205DSS increased with the decreasing solution pH and the presence of CO2at individual pH value.The result was consistent with that analyzed by elongation-to-rupture.SEM observation of fracture surface and cracksNo crack was observed on the circumferential surface of specimens tested in pH4.5solutions without and with CO2. For specimens tested in solutions with pH2.7,cracks were found in both solutions with and without CO2,as shown in Fig.6.Figure7shows the SEM pictures at crack-tip area and the crack initial zone in pH2.7solution without and with CO2.It is seen that the fracture morphology of specimen in both solutions was similar.An island-and-ravine mor-phology,as shown in Fig.7b,d,was observed,where the ruptured c-phase was the island,and d-phase was corroded along crack wall and left ravine surrounding the c-phase island.Figure8shows the fracture surfaces of specimens tested in pH2.7and4.5solutions with and without CO2.In pH 2.7solutions,the fracture showed a brittle feature(Fig.8a,c),morphology of U-type bent specimens soaked in saturated H2S solutions(pH=2.7)for 720h a without CO2and b with CO2while the fracture surface contained ductile dimples in pH 4.5solutions (Fig.8b,d).The presence of CO 2would not alter the fracture feature.DiscussionElectrochemical corrosion mechanism of DSS in H 2S–CO 2solutionThe cathodic and anodic reactions of 2205DSS in the deaerated,acidic (pH \3),H 2S solution are primarily reduction of hydrogen ions and the oxidation of steel to form iron sulﬁde [23]:H þþe !H,ð2ÞH 2S ,H þþHS À,2H þþS 2À;ð3ÞFe þS 2À!FeS #þ2e,ð4ÞFe þHS À!FeS #þH þþ2e :ð5ÞReactions 4and 5would generate a FeS layer on the electrode surface.The FeS ﬁlm was somewhat capable of blocking further dissolution of steel.At an elevated pH,the formation of FeS ﬁlm is favored,resulting in a decreasing anodic current density,as shown in Fig.2.Furthermore,as a cathodic depolarizer,FeS stimulates the reduction of H ?into H that could penetrate into steelsubstrate:surface of 2205DSS specimens tested in pH 2.7solutions a without and b with CO2Fig.7SEM views of cross-section of crack-tip (a ,c )and crack zone (b ,d )on fracture surface.a and b were obtained in solutions without CO 2and pH 2.7,c and d were obtained in solutions with CO 2and pH 2.7H 2S sol H 2S ad ;ð6ÞH 2S ad þe H ad þHS Àad ;ð7ÞHS Àad þe H ad þS 2Àad ;ð8ÞH ad þH ad !H 2;ð9ÞH ads !H abs :ð10ÞIn the presence of CO 2,the dissolved CO 2achieves an equilibrium with water [24,25]:CO 2þH 2O ,H 2CO 3;ð11ÞH 2CO 3,H þþHCO À3;ð12ÞHCO À3,H þþCO 2À3:ð13ÞApparently,dissociation of H 2CO 3serves as an additional source of H ?,contributing to an enhanced cathodic reaction [26].In low pH solution,e.g.,pH 2.7,reduction of hydrogen ions is still the dominant cathodic reaction.Reduction of H 2CO 3and thus the formation of FeCO 3corrosion product ﬁlm are thermodynamically unfavorable [27].As demonstrated in Fig.2,the enhanced cathodic reaction results in the increase of anodic current density in the presence of CO 2in the solution.When solution pH is elevated to 4.5,the presence of CO 2results in an additional cathodic reduction reaction of H 2CO 3:H 2CO 3þe !HCO À3þH :ð14ÞTherefore,the anodic dissolution of steel is enhanced.In summary,although the presence of CO 2in solutionwould enhance the anodic current density of steel,the mechanisms underlying are quite different at low and intermediate pH solutions,which are featured with reduc-tion of hydrogen ions and carbonate acid,respectively.SCC of 2205DSS in H 2S/CO 2solutionsThe present work shows that the susceptibility of 2205DSS to SCC in saturated H 2S solution increases when the solution pH decreases and/or CO 2is purged in the solution (Figs.4,5).In solutions of pH 2.7,SCC of the steel in the absence and presence of CO 2is expected to be a hydrogen-based process,i.e.,HIC dominates the SCC of the steel.As analyzed,the dominant cathodic reaction in low pH solu-tion is hydrogen evolution.Moreover,sulﬁde compounds contained in the solution serve as a poisonous effect to promote hydrogen entry into the steel.The river-bed pat-tern observed in fracture surface of the specimens (Fig.8a,c)is typical of that resulted from HIC.Furthermore,when solution pH is sufﬁciently low,e.g.,pH 2.7in this work,the presence of CO 2in the solution does not alter the fracture mechanism of HIC.Cracks could be initiated no matter if CO 2is present in the system,as seen in Fig.6.However,the SCC susceptibility is enhanced when the test solution contains simultaneously H 2S and CO 2(Fig.5),which is attributed to the enhanced hydrogen evolution.Due to dissociation of H 2CO 3,additional hydrogen ions are generated and then reduced to produce hydrogenatoms,Fig.8Fracture surfaces of SSRT specimens in solutions:a pH 2.7without CO 2,b pH 4.5without CO 2,c pH 2.7with CO 2and d pH 4.5with CO 2contribute to the increasing HIC susceptibility of the steel upon hydrogen permeation.With elevation of solution pH to 4.5,the hydrogen evolution is inhibited,and dissolution is involved in cracking process.Therefore,in addition to the hydrogen effect,anodic dissolution plays an important role in SCC of steel.As seen in Fig.8b,d,the fracture morphology is not completely brittle any more,and ductile dimples are observed due to the decreasing hydrogen-induced embrit-tlement accompanying with the dissolution effect.In general,steels with a two-phase microstructure,such as austenite and ferrite,are more prone to hydrogen-induced embrittlement.In2205DSS,there are two pha-ses,austenite(c-Fe,face centered cubic crystals)and ferrite(d-Fe,body centered cubic crystals),with approx-imately50%volume/volume fraction for each phase.The d-phase usually exhibits high strength and resistance to Cl-attack,and c-Fe can release stress concentration and block crack propagation beyond a-Fe.Consequently,there is a high resistance to SCC of2205DSS[4].However,in case of hydrogen entry into steel,the steel becomes very susceptible to HIC.Since the hydrogen diffusion coefﬁ-cient in c-Fe is low,hydrogen is mainly trapped in irregularities in c-Fe[10,15],and diffuse mainly through the d-Fe grid[28].ConclusionsThe passive current density of2205DSS increases with the decrease of solution pH and the presence of CO2in aerated, H2S-containing solution.In low pH solution,e.g.,pH2.7, the increasing anodic current density is due to cathodic reduction of additional hydrogen ions generated due to dissociation of H2CO3.With elevation of solution pH to 4.5,reduction of H2CO3becomes thermodynamically possible,providing an additional cathodic reduction and resulting in the increase of anodic current density.In solutions with low pH,e.g.,pH2.7,SCC of the steel in the absence and presence of CO2is expected to be a hydrogen-based process,i.e.,HIC dominates the SCC of the steel.When solution pH is sufﬁciently low,the pres-ence of CO2in the solution does not affect the fracture mechanism.However,the SCC susceptibility is enhanced when the test solution is saturated simultaneously with H2S and CO2.With elevation of solution pH to 4.5,the hydrogen evolution is inhibited,and dissolution is involved in cracking process.Even in the presence of CO2,the addi-tional cathodic reduction of H2CO3enhances the anodic reaction rate.Therefore,in addition to the hydrogen effect, anodic dissolution plays an important role in SCC of steel. Acknowledgements This work was supported by Chinese National Science and Technology Infrastructure Platforms Construction Pro-ject(No.2005DKA10400),and Canada Research Chairs Program.References1.Oltra R,Desestret A,Mirabal E,Bizouard JP(1987)Corros Sci27:12512.Van Gelder K,Erlings JG,Damen JWM,Visser A(1987)CorrosSci27:12713.Barteri M,Mancia F,Tama A,Montagna G(1987)Corros Sci27:12394.El-Yazgi AA,Hardie D(1998)Corros Sci40:9095.Liu ZD,Huang LM,Gu T(2006)Mater Perform45:526.Turnbull A,Nimmo B(2005)Corros Eng Sci Technol40:1037.Turnbull A,Grifﬁths A(2003)Corros Eng Sci Technol38:218.Moura V,Kina AY,Tavares SSM,Lima LD,Mainier FB(2008)J Mater Sci43:536.doi:10.1007/s10853-007-1785-59.Vasconcelos IF,Tavares SSM,Reis FEU,Hamilton FG(2009)J Mater Sci44:293.doi:10.1007/s10853-008-3064-510.Umoren S,Obot I,Obi-Egbedi N(2009)J Mater Sci44:274.doi:10.1007/s10853-008-3045-811.Xia SA,Zhou BX,Chen WJ(2008)J Mater Sci43:2990.doi:10.1007/s10853-007-2164-712.Radiguet B,Etienne A,Pareige P,Sauvag X,Valiev R(2008)J Mater Sci43:7338.doi:10.1007/s10853-008-2875-813.Sozanska M,Kłyk-Spyra K(2006)Mater Charact56:39914.De Moraes FD,Bastian FL,Ponciano JA(2005)Corros Sci47:132515.Zakroczymski T,Owczarek E(2002)Acta Mater50:270116.Tsai WT,Chen MS(2000)Corros Sci42:54517.Tsay LW,Young MC,Shin CS,Chan SLI(2007)Fatigue FractEng Mater Struct30:122818.Tsai ST,Yen KP,Shin HC(1998)Corros Sci40:28119.Luu WC,Liu PW,Wu JK(2002)Corros Sci44:178320.Owczarek K,Zakroczymski T(2000)Acta Mater48:305921.Chinese National Standard for Stress Corrosion Cracking Tests,GB T15970,200722.ASTM G30-97(2003)In:Annual Book of ASTM Standards,vol03.02.ASTM International,West Conshohocken,PA23.Mancia F(1987)Corros Sci27:122524.Davies DH,Burstein GT(1980)Corrosion36:41625.Ren CQ,Liu DX,Bai ZQ,Li T(2005)Mater Chem Phys93:30526.Nesic S,Nordsveen M,Nyborg R,Stangeland A(2001)In:Corrosion/2001,Paper No.01040,Nace,Houston27.Nesic S,Postlethwaite J,Olsen S(1996)Corrosion52:28028.Videm K,Kvarekval J(1995)Corrosion51:260。

(候选包壳材料)Corrosion and stress corrosion cracking in supercritical water

Corrosion and stress corrosion cracking in supercritical waterG.S.Was a,*,P.Ampornrat a ,G.Gupta a ,S.Teysseyre a ,E.A.West a ,T.R.Allen b ,K.Sridharan b ,L.Tan b ,Y.Chen b ,X.Ren b ,C.Pister baUniversity of Michigan,Nuclear Engineering,1911Cooley,Ann Arbor,MI 48109,United StatesbUniversity of Wisconsin,United StatesAbstractSupercritical water (SCW)has attracted increasing attention since SCW boiler power plants were implemented to increase the eﬃciency of fossil-based power plants.The SCW reactor (SCWR)design has been selected as one of the Generation IV reactor concepts because of its higher thermal eﬃciency and plant simpliﬁcation as compared to current light water reactors (LWRs).Reactor operating conditions call for a core coolant temperature between 280°C and 620°C at a pressure of 25MPa and maximum expected neutron damage levels to any replaceable or permanent core com-ponent of 15dpa (thermal reactor design)and 100dpa (fast reactor design).Irradiation-induced changes in microstructure (swelling,radiation-induced segregation (RIS),hardening,phase stability)and mechanical properties (strength,thermal and irradiation-induced creep,fatigue)are also major concerns.Throughout the core,corrosion,stress corrosion cracking,and the eﬀect of irradiation on these degradation modes are critical issues.This paper reviews the current understanding of the response of candidate materials for SCWR systems,focusing on the corrosion and stress corrosion cracking response,and highlights the design trade-oﬀs associated with certain alloy systems.Ferritic–martensitic steels generally have the best resistance to stress corrosion cracking,but suﬀer from the worst oxidation.Austenitic stainless steels and Ni-base alloys have better oxidation resistance but are more susceptible to stress corrosion cracking.The promise of grain boundary engineering and surface modiﬁcation in addressing corrosion and stress corrosion cracking performance is discussed.Ó2007Elsevier B.V.All rights reserved.1.IntroductionOne of the most promising advanced reactor concepts for Generation IV nuclear reactors is the Supercritical Water Reactor (SCWR).Operating above the thermodynamic critical point of water (374°C,22.1MPa),the SCWR oﬀers many advan-tages compared to state-of-the-art LWRs including the use of a single phase coolant with high enthalpy,the elimination of components such as steam gener-ators and steam separators and dryers,a low coolant mass inventory resulting in smaller compo-nents,and a much higher eﬃciency ($45%vs.33%in current LWRs).Overall,the design provides a simpliﬁed,reduced volume system with high thermal eﬃciency.The challenge is provided by the substantial increase in operating temperature and pressure as compared to current BWR and PWR designs.The reference design for the SCWR [1,2]calls for an operating pressure of 25MPa and an outlet water temperature up to 620°C,Fig.1.Since supercritical water has never been used in nuclear power applications,there are numerous0022-3115/$-see front matter Ó2007Elsevier B.V.All rights reserved.doi:10.1016/j.jnucmat.2007.05.017*Corresponding author.Fax:+17347634540.E-mail address:gsw@ (G.S.Was).Journal of Nuclear Materials 371(2007)176–201potential problems,particularly with materials.Water in the supercritical phase exhibits properties signiﬁcantly diﬀerent from those of liquid water below the critical point.It acts like a dense gas and its density can vary with temperature and pres-sure from less than 0.1g/cc to values similar to that of water below the critical point.This allows one to ‘tune’the properties of SCW,such as the ion prod-uct,heat capacity,and dielectric constant,to ﬁt the application of interest [1].The corrosive behavior of SCW over this range of densities varies widely depending upon the values of these properties [3,4].Supercritical water will,at the high reactor outlet temperatures,fall in the lower end of the density scale at around 0.2g/cc while having higher density at the reactor inlet.At the low density associated with the reactor outlet,water is a non-polar solvent and can dissolve gases like oxygen to complete mis-cibility.Depending upon what species are present and how much oxygen is present in the solution,SCW in this state can become a very aggressive oxi-dizing environment [3,5].On the other hand,the sol-ubility of ionic species is expected to be extremely low.This is a cause for concern for the general cor-rosion and stress corrosion cracking (SCC)suscepti-bility of the structural materials and fuel elements of reactors.While no experience exists with supercritical water reactors there is a signiﬁcant operating history with supercritical fossil plants [6,7].In fact,as of 2004,there were some 268944MWe (462units)of installed capacity of coal-ﬁred supercritical water power plants worldwide [7].Hence there is signiﬁ-cant industry experience with supercritical water in power generation.However,a nuclear reactor coreis signiﬁcantly diﬀerent from a fossil-ﬁred boiler.One key diﬀerence is geometry.A fossil-ﬁred boiler consists of a large number of ﬁre tubes that circulate water on the inside.These tubes have relatively thick walls,approximately 6–12mm in thickness.Further,the water sees a geometrically smooth and simple surface along its path through the boiler.Contrast this with the core of an SCWR,which con-sists of fuel rods,control rods,and water rods com-prising a fuel assembly with some 145assemblies forming the core.The wall thickness for the fuel rod cladding in the reference SCWR design is 0.63mm and the wall thickness for the water rods is 0.40mm.These very thin components do not pro-vide much margin for corrosion in the cores of supercritical water reactors.Oxide ﬁlms of several hundred micrometer thickness are not unusual for boiler tubes with typical wall thicknesses in the 6–12mm range,but are unacceptable for water rods or fuel cladding.Fig.2illustrates the scale diﬀer-ences between core components in an SCWR and the corresponding components in a fossil-ﬁred SCW power plant.Reactor core components must also contend with irradiation that can aﬀect both the water chemistry and the alloy microstructure.Radiolysis can result in an increase in the concentration of oxygen and other oxidizing species such as H 2O 2that raise the corrosion potential and increase susceptibility to processes such as stress corrosion cracking.Radiol-ysis is not at all understood in supercritical water and pioneering experiments are just now under-way.The very high-temperatures and signiﬁcantly diﬀerent properties of SCW compared to subcritical water make it diﬃcult to estimate the eﬀect of irradiation on this ﬂuid.Initial measurements have shown that virtually no free radical reaction rates follow an Arrhenius law,and so the rate constants must be measured [8].Bartels et al.[8]have made measurements on the radiolysis yield of H 2as a function of temperature and have found that it increases steeply with temperature above about 350°C,Fig.3a.They have also found that rate constants for the reactions H 2+OH (Fig.3b)and OH +OH decrease at higher temperature indicating a slow down of the reaction rate at high-tempera-ture.Since hydrogen addition is a key strategy in controlling corrosion at high-temperature in current reactor designs,an understanding of the dependence of this reaction (Fig.3b)on temperature and radia-tion may be critical to controlling the corrosion potential in the core of an SCWR.A measureofFig.1.Pressure–temperature regime of SCWR operation com-pared to that for current BWRs and PWRs.G.S.Was et al./Journal of Nuclear Materials 371(2007)176–201177the corrosion potential in supercritical water will require development of a reference electrode that can withstand the SCW environment.Once the irra-diated water chemistry is understood so that the corrosion potential can be estimated or measured,then laboratory experiments can be carried out to more accurately simulate the environmental condi-tions expected for the core of a SCWR.Perhaps the most challenging problem is the role of irradiation on the microstructure and how these changes aﬀect stress corrosion cracking.Irradiation assisted stress corrosion cracking has been a generic problem in light water reactors of all types and covering many austenitic and nickel-base alloys [9,10].This paper reviews the current understanding of the response of candidate materials for SCWR sys-tems,focusing on the corrosion and stress corrosion cracking response,and highlights the design trade-oﬀs associated with certain alloy systems.WiththeFig.2.(a)A 1/8assembly model of the 21·21SCWR fuel assembly [2],and (b)comparison of typical fossil boiler tube dimensions to fuel rod and water rod dimensions in the reference SCWR design.178G.S.Was et al./Journal of Nuclear Materials 371(2007)176–201exception of the eﬀect of irradiation on stress corro-sion cracking,the important issues of radiation response and radiolysis are not addressed in this review.2.Experimental programsIn support of the supercritical water reactor pro-gram,corrosion and stress corrosion cracking have been studied in pure supercritical water in ferritic-martenitic steels,austenitic stainless steels,Ni-base alloys,Zr-base alloys,and Ti-base alloys.Test temperatures have ranged from290to732°C. Dissolved oxygen concentration has ranged from <10ppb to8000ppb.Exposure times for corrosion tests have ranged from100to over1000h.In stress corrosion cracking studies,the eﬀect of chemical additions have been examined,speciﬁcally H2SO4, HCl,H2O2,NaCl.Additionally,the aﬀect of system pressure on SCC resistance has been studied.Some speciﬁc alloys have multiple designations. For example,HCM12A and T122are the same composition,as are NF616and T92.In theﬁgures, the alloys designation used is consistent with the reference from which the data was originally pub-lished.Tables1and3can be used to determine alloys with multiple designations.3.CorrosionThis section presents and summarizes the corro-sion in pure supercritical water.Speciﬁc details the corrosion test procedures are described in Ref.[11].The data and descriptions presented are dis-tinct from that on supercritical water oxidation (SCWO)experiments that contain halides for the purpose of breaking down organic materials.This latter database will not be covered in the review thatTable1Summary of experiments on corrosion in pure supercritical waterAlloy Class Alloy Temp.(°C)Water chemistry Exposuretime(h)Austenitic SS304,304L,316,316L,316+Zr,310,310S,310+Zr,TP347H,Sanicro28,D9,800H 290–650Deaerated(<10ppb)to8000ppb dissolved oxygen,100–1026Nickel-base600,625,690,718,825,C22,B2,C276,MAT21,MC 290–600Deaerated(<10ppb)to8000ppb dissolved oxygen,<0.1mS/cm100–575Ferritic–martensitic T91,T91a,T91b,HCM12A(T122),HCM12,HT-9(12Cr–1Mo–1WVNb),NF616(T92),MA956,2.25Cr–1Mo(T11),P2290–650Deaerated(<10ppb)to8000ppb dissolved oxygen,<0.1mS/cm100–1026ODS9Cr,12Cr,F–M,316,Inconel,Hastelloy G-30,19Cr,14Cr–4Al,16Cr–4Al,19Cr–4Al,22Cr–4Al360–60025ppb200–1026Zirconium Zr,Zr–Nb,Zr–Fe–Cr,Zr–Cr–Fe,Zr–Cu–Mo,Zr-2,Zr-4400–500Deaerated(<10ppbdissolved oxygen),<0.1mS/cm<2880Titanium Ti–3Al–2.5V,Ti–6Al–4V,Ti–15Mo–5Zr–3Al,Ti–15V–3Al–3Sn–3Cr 290–5508000ppb dissolved oxygen,0.1mS/cm500G.S.Was et al./Journal of Nuclear Materials371(2007)176–201179follows.The alloy systems,speciﬁc alloys and range of test conditions is summarized in Table1.3.1.Ferritic–martensitic steelsFerritic and martensitic(FM)steels were selected for possible use in supercritical water reactor systems because of their radiation resistance,high thermal conductivity,and low thermal expansion coeﬃcients.To date,international programs have evaluated the following ferritic–martensitic steels: T22,P2,T91,HT9,HCM12,HCM12A(T122), NF616(T92),and numerous oxide dispersion strengthened steels including JAEA9Cr ODS,MA 956and(14–22)Cr–4Al versions[11–19].Surface modiﬁcation,speciﬁcally the implantation of oxy-gen and yttrium,to reduce oxidation rates,has been performed on NF616and HCM12A.3.1.1.Oxide structureFor samples exposed to low dissolved oxygen concentration(less than300ppb),a dual-layer oxide is formed on ferritic–martensitic steels.A typ-ical structure and composition proﬁle for an oxide grown on a ferritic–martensitic steel is shown in the SEM image and EDS proﬁles of Fig.4.Addi-tional information on oxide structure in ferritic–martensitic steels can be seen in Fig.5,an EBSD image.The image and the composition proﬁlesshow two distinct layers.The oxygen content is sim-ilar in both outer and inner oxide layers.The outer oxide is predominantly iron oxide whereas the inner layer contains a signiﬁcant amount of chromium. For300ppb and lower dissolved oxygen concentra-tion,XRD and EBSD have revealed that the outer oxide layer is magnetite(Fe3O4)and the inner layer is an iron–chromium spinel of composition (Fe,Cr)3O4.For samples exposed to high(2000ppb)dis-solved oxygen,an outer hematite layer also forms. The formation of a two-layer oxide in low oxygen concentration and a three-layer oxide in high oxy-gen concentration is consistent with predicted stable phases[20].In addition EDS analysis of the oxygen proﬁle shown in Fig.4b indicates the presence of an internal oxidation transition zone underneath the inner spinel layer.Grain morphology in each oxide layer is revealed by the EBSD map.The spinel layer is composed of small equiaxed grains with a large aspect ratio($0.7 in average),while the magnetite layer is composed of large columnar grains with a small aspect ratio ($0.4in average).The grains in the magnetite layer are elongated along the direction parallel to the growth direction of oxide scale.Carbides retained on the prior austenite grain structure in the inner oxide layer are similar to that in the ferrite phase, indicating that the oxide has grown from the ferrite by solid-state oxidation.3.1.2.Oxide kineticsA strong correlation between increasing tempera-ture and increased oxidation has been found for all ferritic–martensitic steels[13,15,56].The typical eﬀect of time and temperature on oxide growth in ferritic–martensitic steels can be seen in Figs.6and 7,using HCM12A as an example.At higher temper-atures(500°C and600°C),the growth of the oxide follows roughly parabolic kinetics(the growth expo-nent is$0.4for this small data set).At temperatures below the pseudo-critical point(371°C),very little oxide growth is seen out to1026h.The oxide growth increases signiﬁcantly with temperature.Activation energies have been estimated from the oxidationof Fig. 4.Cross-section image(a)and EDS(b)of HCM12A exposed to600°C SCW containing25ppb dissolved oxygen for yers are magnetite,spinel,and metal from left to right.180G.S.Was et al./Journal of Nuclear Materials371(2007)176–201T91,HCM12A,and HT9exposed at temperatures from 400to 600°C and are 189,177,and 172kJ/mol,respectively.Extensive experiments by Graham and Hussey [21]have suggested that in Ni,Cr,Fe,and Fe–Cr alloys,the outer oxides grow predominantlybyFig.5.Cross-section EBSD scanning maps of SCW-exposed samples (a)500°C,25ppb dissolved oxygen,505h and (b)500°C,2000ppb dissolved oxygen,505h,where base metal,spinel,magnetite,and hematite are highlighted in red,blue,yellow,and magenta,respectively.Black areas are unindexed [20].(For interpretation of the references in colour in this ﬁgure legend,the reader is referred to the web version of thisarticle.)G.S.Was et al./Journal of Nuclear Materials 371(2007)176–201181outward diﬀusion of cations.In particular,the acti-vation energy for the diﬀusion of iron in Fe 3O 4is 230kJ/mol,for nickel in NiO the value is 234kJ/mol,and for chromium in Cr 2O 3,the value is 420kJ/mol [22].The activation energy for diﬀusion of oxygen in Fe 2O 3is 610kJ/mol [21],and while that for Fe 3O 4is considerably smaller,the diﬀusion coeﬃcients cannot account for the measured oxide thickness.Nevertheless,evidence suggests that the inner oxide grows by the inward diﬀusion of oxygen.The diﬀusion is likely aﬀected by short-circuit paths such as pores,cracks and grain boundaries,which would account for the higher rates.For times to 1026h,the oxides that develop on traditional (non-ODS versions)ferritic–martensitic steels are stable,maintain a constant average density,and do not spall.This is evident in the data presented in Fig.8that shows the weight gain is proportional to the oxide thickness.The oxide den-sity is greater for samples exposed at 2000ppb as compared to samples exposed at 25ppb dissolved oxygen.Plan view and cross-sectional images of the dual phase oxides also do not show any indica-tion of spallation.3.1.3.Eﬀect of dissolved oxygenThe oxide growth rate and associated weight gain of ferritic–martensitic steels are dependent on the dissolved oxygen concentration.This dependence is shown in Fig.9using data from HCM12A.For dissolved oxygen concentrations between 10and 300ppb,the weight gain associated with oxidegrowth decreases slightly with dissolved oxygen concentration.However,the weight gain increases signiﬁcantly for samples exposed to 2000ppb dis-solved oxygen,due to the development of a thicker oxide layer.In addition,the development of a den-ser oxide layer and the formation of a hematite layer formed at the higher dissolved oxygen content SCW may also play a role in the upsurge in weight gain observed for samples exposed to 2000ppb dissolved oxygen SCW.Combined water chemistry control in fossil plants [23,24]adds small amounts of oxygen to enhance the formation of hematite crystals between the magnetite grains,thus reducing the oxidation rate,perhaps by reducing the diﬀusion of oxygen through the multi-phase ﬁlm.For the studies sup-porting SCWRs,signiﬁcant hematite crystals have not been found between the magnetite grains at 10–300ppb oxygen where oxidation is the slowest.3.1.4.Eﬀect of bulk chromium concentrationFor conventional ferritic–martensitic steels,increasing the bulk chromium concentration reduces the weight gain due to oxidation.An exam-ple of this correlation is shown in Fig.10where the 9at.%Cr alloy NF616has a greater weight gain than the 12at.%alloy HCM12A.The same trend is seen in the weight gain data for T91(9Cr)and HT9(12Cr)for all temperatures and times evalu-ated.These results agree with those from Jang [15],as well as Cho and Kimura [16,25]who exam-ined weight gain over a range of Cr contentandFig.8.Weight gain as a function of oxide thickness for HCM12A exposed to 25ppb and 2000ppb oxygen at 500°C.Average oxide density (the slope of the plotted lines)is 1526mg/cm 2for 2000ppb dissolved oxygen and 1338mg/cm 2for 25ppb dissolved oxygen [20].182G.S.Was et al./Journal of Nuclear Materials 371(2007)176–201found that increasing Cr led to decreasing weight gain.A diﬀerent behavior is noted in oxide dispersion strengthened ferritic–martensitic steels.The weight gain data for the JAEA9Cr ODS alloy is also included in Fig.10.Even though this alloy only has9at.%Cr,it shows the lowest weight gain of any of the tested ferritic–martensitic steels.The ODS spinel that forms tends to become more porous at higher exposure times[26].3.1.5.Oxidation reduction methodsAs was mentioned in the introduction,the allow-able oxide thickness must be limited for thin-walled cladding or water rods.For a1026h exposure at 600°C,the oxide thickness in HCM12A is approx-imately65l m,approximately15%of the thickness of the original water rod wall.For ferritic–martens-itic steels to be acceptable for thin-walled compo-nents exposed to supercritical water,the thickness of the oxide(and the associated metal loss)must be reduced.One method for improvement is seen from the ODS data in Fig.10.The ODS steels typically show lower oxidation than conventional ferritic–martens-itic steels.The ODS steels have two signiﬁcant diﬀerences from conventional ferritic–martensitic steels.First,they include nanometer sized Y–Ti–O particles,added for strengthening.A comparison of the9Cr ODS alloy with NF616,Figs.11and 12,shows that the ODS alloy has a much deeper internal oxidation layer.Thus the net conversion of metal to spinel appears to be driven by oxygen diﬀusion into the metal rather than cation diﬀusion to the oxide surface.Detailed microscopy indicates the formation of Y–Cr-rich oxides along grain boundaries in the steel near the metal–oxide inter-face may act to block cation diﬀusion[26].The inner spinel layer that forms in the ODS alloy is more por-ous,and the lower density,combined with a thinner oxide,leads to a smaller weight gain in the ODS material.Additionally,the ODS materials typically have smaller grain sizes than conventional ferritic–martensitic steels.The increased diﬀusion length along short-circuit diﬀusion paths may slow oxidation.A second method that shows promise in slowing oxidation in ferritic–martensitic steels is surfaceFig.11.(a)Cross-sectional SEM image of the9Cr ODS ferritic steel after exposure to supercritical water at500°C for1026h and (b)corresponding composition proﬁle across the oxide thickness[26].G.S.Was et al./Journal of Nuclear Materials371(2007)176–201183composition modiﬁcation.Both oxygen and yttrium have been implanted into the surface of various ferritic–martensitic steels.The change in weight gain with various surface implantation conditions is shown in Fig.13.At 500°C,oxygen implantation reduced the weight gain in T91,HCM12A,and HT9.The reduction in oxide thickness in HT9has an associated change in the oxide texture early in the development of the oxide,but at longer times,the textures are similar between samples with and without oxygen pre-implantation [27].One possible explanation for the texture is that,among randomly orientated initial grains,some with certain crystal orientations grow faster than the others to release the stress introduced by the ion implantation.A sec-ond possibility is that bombardment with oxygen ions may increase nucleation sites with certain pre-ferred orientations at the initial stage of oxide for-mation,resulting in a denser textured oxide layer [17].At 600°C,the oxygen pre-implantation was not eﬀective in reducing weight gain due to oxidation,but pre-implantation of yttrium strongly reduced the oxide thickness in both NF616and HCM12A.A thin layer of yttrium is incorporated into the mag-netite layer that appears to slow cation diﬀusion through the magnetite layer,thus reducing the oxidation by approximately 50%,Fig.14.3.2.Austenitic steelsAustenitic Fe-base steels were selected for possi-ble use in supercritical water systems becauseofFig.12.(a)Cross-sectional SEM image of the 9Cr NF616ferritic steel after exposure to supercritical water at 500°C for 1026h and (b)corresponding composition proﬁle across the oxide thickness [26].Fig.13.Eﬀect of oxygen and yttrium surface implantation at 500°C,and 600°C on T91,HCM12A,HT9,NF616,and 9Cr ODS.184G.S.Was et al./Journal of Nuclear Materials 371(2007)176–201their corrosion resistance and relative radiation resistance compared to Ni-base alloys.To date,international programs have evaluated the follow-ing austenitic steels:304L,304,304H,316L,316,D9,310S,and 800H [11,13,14,28–30].Grain bound-ary engineering has been performed on Alloy 800H to reduce oxide spallation.3.2.1.Oxide structureMost results on austenitic stainless steels reveal that the oxide consists of a two-or three-layer struc-ture,consistent with that observed during exposure to air,vacuum or subcritical water [57–59].The outer layer generally consists of magnetite with an inner layer that is rich in chromium and is either an iron–chromium spinel or an iron chromium oxide with a hematite structure [11,50,59].As in the case of ferritic steels an internal oxidation layer is also observed between the inner oxide layer and the base metal as evidenced by a gradually decreas-ing oxygen diﬀusion proﬁle in this transition zone.A typical structure and composition proﬁle for an oxide grown on an austenitic steel (800H)is shown in the SEM image in Fig.15.The oxide structure is somewhat similar to those formed in ferritic–martensitic steels,except that the outer oxide layer is composed of both magnetite and hematite.An additional diﬀerence between austen-itic and ferritic–martensitic steels is the stability of the outer oxide layer.In many of the austenitic stainless steels with higher bulk concentrations of nickel and chromium,the outer oxide layer has a tendency to spall,as demonstrated in the plan view images from D9exposed to 500°C 2000ppb SCW as shown in Fig.16.3.2.2.Oxide kineticsAustenitic stainless steels have a smaller weight gain than ferritic–martensitic steels [11,13,56].An example of typical kinetics for tests to 1026hisFig.14.Oxide thickness and compositional proﬁle in HCM12A (top)and HCM12A with surface implantation of yttrium (middle).A thin layer of yttrium becomes incorporated into the outer magnetite layer (bottom,area marked 1)with a resulting $50%thickness inoxide.Fig.15.Cross-section of oxide formed on Alloy 800H exposed to 500°C SCW with 25ppb dissolved oxygen concentration for 505h [31].G.S.Was et al./Journal of Nuclear Materials 371(2007)176–201185shown in Fig.17for alloy D9.For 500°C and 600°C,the oxide kinetics appear parabolic,but the data scatter is greater in austenitic alloys than in ferritic–martensitic steels.In some austenitic alloys,a portion of this scatter is attributed to spall-ation.The oxidation rate in austenitic alloys is smal-ler than in ferritic–martensitic paringFigs.7and 17,at 600°C the oxidation at 1026h is roughly a factor of 4larger in HCM12A than in D9.Like ferritic–martensitic steels,the oxidation rate increases dramatically with increasing temperature.The temperature dependence of alloy D9is shown in Fig.18.Because of spallation,as evidenced for D9in Fig.19,a simple relation between oxide thick-Fig.16.SEM morphologies of the D9samples after exposure to 2000ppb SCW at 500°C for (a)168h,(b)335h and (c,d)503h [60].ness and weight gain is not possible in many austen-itic alloys.Activation energy has been calculated for some austenitic steels,speciﬁcally 210kJ/mol for 304L and 214kJ/mol for 316L,higher than the energy measured in T91,HCM12A,and HT9.3.2.3.Eﬀect of dissolved oxygenThe eﬀect of dissolved oxygen is more complex in austenitic alloys than in ferritic–martensitic steels.This is demonstrated in Fig.20for D9and 21for 316and 316L.For D9exposed at 500°C,at short times,the weight gain is smaller at very high (2000ppb)dissolved oxygen than at low (25ppb dissolved oxygen).At longer times (between 333and 505h),the oxidation rate of the D9exposedto 2000ppb dissolved oxygen increases signiﬁcantly.It is noted for the D9samples exposed to 25ppb oxygen content,particularly for longer exposure times that the weight gain remains nearly constant,an aﬀect that is attributed to oxide spallation in these alloys.The weight gain measurements shown in Fig.20represent the cumulative eﬀects of weight gain due to oxidation as well as spallation.The weight loss due to spallation counterbalances the weight gain due to the growth of the oxide layer.This observation is supported by our SEM observa-tions of oxide spallation in D9steels.It is speculated that this eﬀect would be observed for the samples exposed to higher oxygen SCW if the samples had been exposed to longer durations.Weight gain rate for 316and 316L as a function of temperature from this work is compared to that of Kasahara et al.[13],who exposed 316L in a static autoclave at 8000ppb dissolved oxygen,in Fig.21.At low temperatures,the oxidation is minimal and no signiﬁcant diﬀerence is noted between 316and 316L or between exposures at diﬀerent oxygen con-centration.At 500°C,higher dissolved oxygen leads to greater weight gain in 316.At 550°C,the weight gain rate is actually higher for the deoxygenated (<10ppb)case than for the 8000ppb case.The eﬀect of oxygen is not as straightforward in the austenitic steels as was seen in the ferritic–mar-tensitic steels and greater study is needed toidentifyFig.19.Oxide thickness for D9exposed to 500°C SCW at 25ppb dissolved oxygen for 1026h [60].。

固体力学英语词汇翻译(2)

固体力学英语词汇翻译(2)固体力学英语词汇翻译(2)裂纹面 crack surface裂纹尖端 crack tip裂尖张角 crack tip opening angle, ctoa裂尖张开位移 crack tip opening displacement, ctod 裂尖奇异场 crack tip singularity field裂纹扩展速率 crack growth rate稳定裂纹扩展 stable crack growth定常裂纹扩展 steady crack growth亚临界裂纹扩展 subcritical crack growth裂纹[扩展]减速 crack retardation止裂 crack arrest止裂韧度 arrest toughness断裂类型 fracture mode滑开型 sliding mode张开型 opening mode撕开型 tearing mode复合型 mixed mode撕裂 tearing撕裂模量 tearing modulus断裂准则 fracture criterionj积分 j-integralj阻力曲线 j-resistance curve断裂韧度 fracture toughness应力强度因子 stress inteity factorhrr场 hutchion-rice-rosengren field守恒积分 coervation integral有效应力张量 effective stress teor应变能密度 strain energy deity能量释放率 energy release rate内聚区 cohesive zone塑性区 plastic zone张拉区 stretched zone热影响区 heat affected zone, haz延脆转变温度 brittle-ductile traition temperature剪切带 shear band剪切唇 shear lip无损检测 non-destructive ipection双边缺口试件 double edge notched specimen, den specimen单边缺口试件 single edge notched specimen, sen specimen三点弯曲试件 three point bending specimen, tpb specimen中心裂纹拉伸试件 center cracked teion specimen, cct specimen 中心裂纹板试件 center cracked panel specimen, ccp specimen 紧凑拉伸试件 compact teion specimen, ct specimen大范围屈服 large scale yielding小范围攻屈服 small scale yielding韦布尔分布 weibull distribution帕里斯公式 paris formula空穴化 cavitation应力腐蚀 stress corrosion概率风险判定 probabilistic risk assessment, pra损伤力学 damage mechanics损伤 damage连续介质损伤力学 continuum damage mechanics细观损伤力学 microscopic damage mechanics累积损伤 accumulated damage脆性损伤 brittle damage延性损伤 ductile damage宏观损伤 macroscopic damage细观损伤 microscopic damage微观损伤 microscopic damage损伤准则 damage criterion损伤演化方程 damage evolution equation损伤软化 damage softening损伤强化 damage strengthening损伤张量 damage teor损伤阈值 damage threshold损伤变量 damage variable损伤矢量 damage vector损伤区 damage zone疲劳 fatigue低周疲劳 low cycle fatigue应力疲劳 stress fatigue随机疲劳 random fatigue蠕变疲劳 creep fatigue腐蚀疲劳 corrosion fatigue疲劳损伤 fatigue damage疲劳失效 fatigue failure疲劳断裂 fatigue fracture疲劳裂纹 fatigue crack疲劳寿命 fatigue life疲劳破坏 fatigue rupture疲劳强度 fatigue strength疲劳辉纹 fatigue striatio疲劳阈值 fatigue threshold交变载荷 alternating load交变应力 alternating stress应力幅值 stress amplitude应变疲劳 strain fatigue应力循环 stress cycle应力比 stress ratio安全寿命 safe life过载效应 overloading effect循环硬化 cyclic hardening循环软化 cyclic softening环境效应 environmental effect裂纹片 crack gage裂纹扩展 crack growth, crack propagation 裂纹萌生 crack initiation循环比 cycle ratio实验应力分析 experimental stress analysis工作[应变]片 active[strain] gage基底材料 backing material应力计 stress gage零[点]飘移 zero shift, zero drift应变测量 strain measurement应变计 strain gage应变指示器 strain indicator应变花 strain rosette应变灵敏度 strain seitivity机械式应变仪 mechanical strain gage直角应变花 rectangular rosette引伸仪 exteometer应变遥测 telemetering of strain横向灵敏系数 travee gage factor横向灵敏度 travee seitivity焊接式应变计 weldable strain gage平衡电桥 balanced bridge粘贴式应变计 bonded strain gage粘贴箔式应变计 bonded foiled gage粘贴丝式应变计 bonded wire gage桥路平衡 bridge balancing电容应变计 capacitance strain gage补偿片 compeation technique补偿技术 compeation technique基准电桥 reference bridge电阻应变计 resistance strain gage温度自补偿应变计 self-temperature compeating gage 半导体应变计 semiconductor strain gage集流器 slip ring应变放大镜 strain amplifier疲劳寿命计 fatigue life gage电感应变计 inductance [strain] gage光[测]力学 photomechanics光弹性 photoelasticity光塑性 photoplasticity杨氏条纹 young fringe双折射效应 birefrigent effect等位移线 contour of equal displacement暗条纹 dark fringe条纹倍增 fringe multiplication干涉条纹 interference fringe等差线 isochromatic等倾线 isoclinic等和线 isopachic应力光学定律 stress- optic law主应力迹线 isostatic亮条纹 light fringe光程差 optical path difference热光弹性 photo-thermo -elasticity光弹性贴片法 photoelastic coating method光弹性夹片法 photoelastic sandwich method动态光弹性 dynamic photo-elasticity空间滤波 spatial filtering空间频率 spatial frequency起偏镜 polarizer反射式光弹性仪 reflection polariscope残余双折射效应 residual birefringent effect应变条纹值 strain fringe value应变光学灵敏度 strain-optic seitivity应力冻结效应 stress freezing effect应力条纹值 stress fringe value应力光图 stress-optic pattern暂时双折射效应 temporary birefringent effect脉冲全息法 pulsed holography透射式光弹性仪 tramission polariscope实时全息干涉法 real-time holographic interferometry 网格法 grid method全息光弹性法 holo-photoelasticity全息图 hologram全息照相 holograph全息干涉法 holographic interferometry全息云纹法 holographic moire technique全息术 holography全场分析法 whole-field analysis散斑干涉法 speckle interferometry散斑 speckle错位散斑干涉法 speckle-shearing interferometry, shearography 散斑图 specklegram白光散斑法 white-light speckle method云纹干涉法 moire interferometry[叠栅]云纹 moire fringe[叠栅]云纹法 moire method云纹图 moire pattern离面云纹法 off-plane moire method参考栅 reference grating试件栅 specimen grating分析栅 analyzer grating面内云纹法 in-plane moire method脆性涂层法 brittle-coating method条带法 strip coating method坐标变换 traformation of coordinates计算结构力学 computational structural mechanics加权残量法 weighted residual method有限差分法 finite difference method有限[单]元法 finite element method配点法 point collocation里茨法 ritz method广义变分原理 generalized variational principle最小二乘法 least square method胡[海昌]一鹫津原理 hu-washizu principle赫林格-赖斯纳原理 hellinger-reissner principle修正变分原理 modified variational principle约束变分原理 cotrained variational principle 混合法 mixed method杂交法 hybrid method边界解法 boundary solution method有限条法 finite strip method半解析法 semi-analytical method协调元 conforming element非协调元 non-conforming element混合元 mixed element杂交元 hybrid element边界元 boundary element强迫边界条件 forced boundary condition自然边界条件 natural boundary condition离散化 discretization离散系统 discrete system连续问题 continuous problem广义位移 generalized displacement广义载荷 generalized load广义应变 generalized strain广义应力 generalized stress界面变量 interface variable节点 node, nodal point[单]元 element角节点 corner node边节点 mid-side node内节点 internal node无节点变量 nodeless variable杆元 bar element桁架杆元 truss element梁元 beam element二维元 two-dimeional element一维元 one-dimeional element三维元 three-dimeional element轴对称元 axisymmetric element板元 plate element壳元 shell element厚板元 thick plate element三角形元 triangular element四边形元 quadrilateral element四面体元 tetrahedral element曲线元 curved element二次元 quadratic element线性元 linear element三次元 cubic element四次元 quartic element等参[数]元 isoparametric element超参数元 super-parametric element亚参数元 sub-parametric element节点数可变元 variable-number-node element 拉格朗日元 lagrange element拉格朗日族 lagrange family巧凑边点元 serendipity element巧凑边点族 serendipity family无限元 infinite element单元分析 element analysis单元特性 element characteristics刚度矩阵 stiffness matrix几何矩阵 geometric matrix等效节点力 equivalent nodal force节点位移 nodal displacement节点载荷 nodal load位移矢量 displacement vector载荷矢量 load vector质量矩阵 mass matrix集总质量矩阵 lumped mass matrix相容质量矩阵 coistent mass matrix阻尼矩阵 damping matrix瑞利阻尼 rayleigh damping刚度矩阵的组集 assembly of stiffness matrices 载荷矢量的组集 coistent mass matrix质量矩阵的组集 assembly of mass matrices单元的组集 assembly of elements局部坐标系 local coordinate system局部坐标 local coordinate面积坐标 area coordinates体积坐标 volume coordinates曲线坐标 curvilinear coordinates静凝聚 static condeation合同变换 contragradient traformation形状函数 shape function试探函数 trial function检验函数 test function权函数 weight function样条函数 spline function代用函数 substitute function降阶积分 reduced integration零能模式 zero-energy modep收敛 p-convergenceh收敛 h-convergence掺混插值 blended interpolation等参数映射 isoparametric mapping双线性插值 bilinear interpolation小块检验 patch test非协调模式 incompatible mode节点号 node number单元号 element number带宽 band width带状矩阵 banded matrix变带状矩阵 profile matrix带宽最小化 minimization of band width波前法 frontal method子空间迭代法 subspace iteration method宝岛优品—倾心为你打造精品文档行列式搜索法 determinant search method逐步法 step-by-step method纽马克法 newmark威尔逊法 wilson拟牛顿法 quasi-newton method牛顿-拉弗森法 newton-raphson method增量法 incremental method初应变 initial strain初应力 initial stress切线刚度矩阵 tangent stiffness matrix割线刚度矩阵 secant stiffness matrix模态叠加法 mode superposition method平衡迭代 equilibrium iteration子结构 substructure子结构法 substructure technique超单元 super-element网格生成 mesh generation结构分析程序 structural analysis program前处理 pre-processing后处理 post-processing网格细化 mesh refinement应力光顺 stress smoothing组合结构 composite structure固体力学英语词汇翻译(2) 相关内容:力学名词英语翻译固体力学英语词汇翻译(1)流体力学英语词汇翻译(2)流体力学英语词汇翻译(1)统计相关英语词汇核工业相关词汇的英语翻译数学常用英语词汇数学新词汇的中英翻译查看更多>> 数学物理英语词汇宝岛优品—倾心为你打造精品文档。

弹性力学专业英语英汉互译词汇

弹性力学elasticity弹性理论theory of elasticity 均匀应力状态homogeneous state of stress 应力不变量stress invariant应变不变量strain invariant应变椭球strain ellipsoid 均匀应变状态homogeneous state ofstrain 应变协调方程equation of straincompatibility 拉梅常量Lame constants 各向同性弹性isotropic elasticity 旋转圆盘rotating circular disk 楔wedge开尔文问题Kelvin problem 布西内斯克问题Boussinesq problem艾里应力函数Airy stress function克罗索夫--穆斯赫利什维Kolosoff-利法Muskhelishvili method 基尔霍夫假设Kirchhoff hypothesis 板Plate矩形板Rectangular plate圆板Circular plate环板Annular plate波纹板Corrugated plate加劲板Stiffened plate,reinforcedPlate 中厚板Plate of moderate thickness 弯[曲]应力函数Stress function of bending 壳Shell扁壳Shallow shell旋转壳Revolutionary shell球壳Spherical shell [圆]柱壳Cylindrical shell 锥壳Conical shell环壳Toroidal shell封闭壳Closed shell波纹壳Corrugated shell扭[转]应力函数Stress function of torsion 翘曲函数Warping function半逆解法semi-inverse method瑞利--里茨法Rayleigh-Ritz method 松弛法Relaxation method莱维法Levy method松弛Relaxation 量纲分析Dimensional analysis自相似[性] self-similarity 影响面Influence surface接触应力Contact stress赫兹理论Hertz theory协调接触Conforming contact滑动接触Sliding contact滚动接触Rolling contact压入Indentation各向异性弹性Anisotropic elasticity 颗粒材料Granular material散体力学Mechanics of granular media 热弹性Thermoelasticity超弹性Hyperelasticity粘弹性Viscoelasticity对应原理Correspondence principle 褶皱Wrinkle塑性全量理论Total theory of plasticity 滑动Sliding微滑Microslip粗糙度Roughness非线性弹性Nonlinear elasticity 大挠度Large deflection突弹跳变snap-through有限变形Finite deformation格林应变Green strain阿尔曼西应变Almansi strain弹性动力学Dynamic elasticity运动方程Equation of motion准静态的Quasi-static气动弹性Aeroelasticity水弹性Hydroelasticity颤振Flutter弹性波Elastic wave简单波Simple wave柱面波Cylindrical wave水平剪切波Horizontal shear wave竖直剪切波Vertical shear wave 体波body wave无旋波Irrotational wave畸变波Distortion wave膨胀波Dilatation wave瑞利波Rayleigh wave等容波Equivoluminal wave勒夫波Love wave界面波Interfacial wave边缘效应edge effect塑性力学Plasticity可成形性Formability金属成形Metal forming耐撞性Crashworthiness结构抗撞毁性Structural crashworthiness 拉拔Drawing 破坏机构Collapse mechanism 回弹Springback挤压Extrusion冲压Stamping穿透Perforation层裂Spalling 塑性理论Theory of plasticity安定[性]理论Shake-down theory运动安定定理kinematic shake-down theorem静力安定定理Static shake-down theorem 率相关理论rate dependent theorem 载荷因子load factor加载准则Loading criterion加载函数Loading function加载面Loading surface塑性加载Plastic loading塑性加载波Plastic loading wave 简单加载Simple loading比例加载Proportional loading 卸载Unloading卸载波Unloading wave冲击载荷Impulsive load阶跃载荷step load脉冲载荷pulse load极限载荷limit load中性变载nentral loading拉抻失稳instability in tension 加速度波acceleration wave本构方程constitutive equation 完全解complete solution名义应力nominal stress过应力over-stress真应力true stress等效应力equivalent stress流动应力flow stress应力间断stress discontinuity应力空间stress space主应力空间principal stress space静水应力状态hydrostatic state of stress 对数应变logarithmic strain工程应变engineering strain等效应变equivalent strain应变局部化strain localization 应变率strain rate应变率敏感性strain rate sensitivity 应变空间strain space有限应变finite strain塑性应变增量plastic strain increment 累积塑性应变accumulated plastic strain 永久变形permanent deformation内变量internal variable应变软化strain-softening理想刚塑性材料rigid-perfectly plasticMaterial刚塑性材料rigid-plastic material理想塑性材料perfectl plastic material 材料稳定性stability of material应变偏张量deviatoric tensor of strain 应力偏张量deviatori tensor of stress 应变球张量spherical tensor of strain 应力球张量spherical tensor of stress 路径相关性path-dependency线性强化linear strain-hardening应变强化strain-hardening随动强化kinematic hardening各向同性强化isotropic hardening 强化模量strain-hardening modulus幂强化power hardening塑性极限弯矩plastic limit bendingMoment塑性极限扭矩plastic limit torque弹塑性弯曲elastic-plastic bending弹塑性交界面elastic-plastic interface 弹塑性扭转elastic-plastic torsion 粘塑性Viscoplasticity非弹性Inelasticity理想弹塑性材料elastic-perfectly plasticMaterial 极限分析limit analysis极限设计limit design极限面limit surface上限定理upper bound theorem上屈服点upper yield point下限定理lower bound theorem下屈服点lower yield point界限定理bound theorem初始屈服面initial yield surface后继屈服面subsequent yield surface屈服面[的]外凸性convexity of yield surface 截面形状因子shape factor of cross-section沙堆比拟sand heap analogy 屈服Yield 屈服条件yield condition屈服准则yield criterion屈服函数yield function屈服面yield surface塑性势plastic potential 能量吸收装置energy absorbing device 能量耗散率energy absorbing device 塑性动力学dynamic plasticity 塑性动力屈曲dynamic plastic buckling 塑性动力响应dynamic plastic response 塑性波plastic wave 运动容许场kinematically admissibleField 静力容许场statically admissibleField 流动法则flow rule速度间断velocity discontinuity滑移线slip-lines滑移线场slip-lines field移行塑性铰travelling plastic hinge 塑性增量理论incremental theory ofPlasticity 米泽斯屈服准则Mises yield criterion 普朗特--罗伊斯关系prandtl- Reuss relation 特雷斯卡屈服准则Tresca yield criterion洛德应力参数Lode stress parameter莱维--米泽斯关系Levy-Mises relation亨基应力方程Hencky stress equation赫艾--韦斯特加德应力空Haigh-Westergaard 间stress space洛德应变参数Lode strain parameter德鲁克公设Drucker postulate盖林格速度方程Geiringer velocityEquation结构力学structural mechanics结构分析structural analysis结构动力学structural dynamics拱Arch三铰拱three-hinged arch抛物线拱parabolic arch圆拱circular arch穹顶Dome空间结构space structure空间桁架space truss雪载[荷] snow load风载[荷] wind load土压力earth pressure地震载荷earthquake loading弹簧支座spring support支座位移support displacement支座沉降support settlement超静定次数degree of indeterminacy机动分析kinematic analysis结点法method of joints截面法method of sections结点力joint forces共轭位移conjugate displacement影响线influence line 三弯矩方程three-moment equation单位虚力unit virtual force刚度系数stiffness coefficient柔度系数flexibility coefficient力矩分配moment distribution力矩分配法moment distribution method 力矩再分配moment redistribution分配系数distribution factor矩阵位移法matri displacement method 单元刚度矩阵element stiffness matrix 单元应变矩阵element strain matrix 总体坐标global coordinates贝蒂定理Betti theorem高斯--若尔当消去法Gauss-Jordan eliminationMethod 屈曲模态buckling mode 复合材料力学mechanics of composites 复合材料composite material 纤维复合材料fibrous composite单向复合材料unidirectional composite泡沫复合材料foamed composite颗粒复合材料particulate composite 层板Laminate夹层板sandwich panel正交层板cross-ply laminate 斜交层板angle-ply laminate 层片Ply 多胞固体cellular solid 膨胀Expansion压实Debulk劣化Degradation脱层Delamination脱粘Debond 纤维应力fiber stress层应力ply stress层应变ply strain层间应力interlaminar stress比强度specific strength强度折减系数strength reduction factor 强度应力比strength -stress ratio 横向剪切模量transverse shear modulus 横观各向同性transverse isotropy正交各向异Orthotropy剪滞分析shear lag analysis短纤维chopped fiber长纤维continuous fiber纤维方向fiber direction纤维断裂fiber break纤维拔脱fiber pull-out纤维增强fiber reinforcement致密化Densification最小重量设计optimum weight design网格分析法netting analysis 混合律rule of mixture失效准则failure criterion蔡--吴失效准则Tsai-W u failure criterion 达格代尔模型Dugdale model 断裂力学fracture mechanics概率断裂力学probabilistic fractureMechanics格里菲思理论Griffith theory线弹性断裂力学linear elastic fracturemechanics, LEFM弹塑性断裂力学elastic-plastic fracturemecha-nics, EPFM 断裂Fracture 脆性断裂brittle fracture解理断裂cleavage fracture蠕变断裂creep fracture延性断裂ductile fracture晶间断裂inter-granular fracture 准解理断裂quasi-cleavage fracture 穿晶断裂trans-granular fracture 裂纹Crack裂缝Flaw缺陷Defect割缝Slit微裂纹Microcrack折裂Kink 椭圆裂纹elliptical crack深埋裂纹embedded crack[钱]币状裂纹penny-shape crack 预制裂纹Precrack短裂纹short crack表面裂纹surface crack裂纹钝化crack blunting裂纹分叉crack branching裂纹闭合crack closure裂纹前缘crack front裂纹嘴crack mouth裂纹张开角crack opening angle,COA 裂纹张开位移crack opening displacement,COD 裂纹阻力crack resistance裂纹面crack surface裂纹尖端crack tip裂尖张角crack tip opening angle,CTOA裂尖张开位移crack tip openingdisplacement, CTOD裂尖奇异场crack tip singularityField裂纹扩展速率crack growth rate稳定裂纹扩展stable crack growth定常裂纹扩展steady crack growth亚临界裂纹扩展subcritical crack growth 裂纹[扩展]减速crack retardation 止裂crack arrest 止裂韧度arrest toughness断裂类型fracture mode滑开型sliding mode张开型opening mode撕开型tearing mode复合型mixed mode撕裂Tearing 撕裂模量tearing modulus断裂准则fracture criterionJ积分J-integral J阻力曲线J-resistance curve断裂韧度fracture toughness应力强度因子stress intensity factor HRR场Hutchinson-Rice-RosengrenField 守恒积分conservation integral 有效应力张量effective stress tensor 应变能密度strain energy density 能量释放率energy release rate 内聚区cohesive zone塑性区plastic zone张拉区stretched zone热影响区heat affected zone, HAZ 延脆转变温度brittle-ductile transitiontempe- rature 剪切带shear band剪切唇shear lip无损检测non-destructive inspection 双边缺口试件double edge notchedspecimen, DEN specimen 单边缺口试件single edge notchedspecimen, SEN specimen 三点弯曲试件three point bendingspecimen, TPB specimen 中心裂纹拉伸试件center cracked tensionspecimen, CCT specimen 中心裂纹板试件center cracked panelspecimen, CCP specimen 紧凑拉伸试件compact tension specimen,CT specimen 大范围屈服large scale yielding小范围攻屈服small scale yielding 韦布尔分布Weibull distribution 帕里斯公式paris formula 空穴化Cavitation应力腐蚀stress corrosion概率风险判定probabilistic riskassessment, PRA 损伤力学damage mechanics 损伤Damage连续介质损伤力学continuum damage mechanics 细观损伤力学microscopic damage mechanics 累积损伤accumulated damage脆性损伤brittle damage延性损伤ductile damage宏观损伤macroscopic damage细观损伤microscopic damage微观损伤microscopic damage损伤准则damage criterion损伤演化方程damage evolution equation 损伤软化damage softening损伤强化damage strengthening损伤张量damage tensor损伤阈值damage threshold损伤变量damage variable损伤矢量damage vector损伤区damage zone疲劳Fatigue 低周疲劳low cycle fatigue应力疲劳stress fatigue随机疲劳random fatigue蠕变疲劳creep fatigue腐蚀疲劳corrosion fatigue疲劳损伤fatigue damage疲劳失效fatigue failure 疲劳断裂fatigue fracture 疲劳裂纹fatigue crack 疲劳寿命fatigue life疲劳破坏fatigue rupture 疲劳强度fatigue strength 疲劳辉纹fatigue striations 疲劳阈值fatigue threshold 交变载荷alternating load 交变应力alternating stress 应力幅值stress amplitude 应变疲劳strain fatigue 应力循环stress cycle应力比stress ratio安全寿命safe life过载效应overloading effect 循环硬化cyclic hardening 循环软化cyclic softening 环境效应environmental effect 裂纹片crack gage裂纹扩展crack growth, crackPropagation 裂纹萌生crack initiation 循环比cycle ratio实验应力分析experimental stressAnalysis工作[应变]片active[strain] gage基底材料backing material应力计stress gage 零[点]飘移zero shift, zero drift 应变测量strain measurement应变计strain gage 应变指示器strain indicator 应变花strain rosette 应变灵敏度strain sensitivity机械式应变仪mechanical strain gage 直角应变花rectangular rosette 引伸仪Extensometer应变遥测telemetering of strain 横向灵敏系数transverse gage factor 横向灵敏度transverse sensitivity 焊接式应变计weldable strain gage 平衡电桥balanced bridge粘贴式应变计bonded strain gage粘贴箔式应变计bonded foiled gage粘贴丝式应变计bonded wire gage 桥路平衡bridge balancing电容应变计capacitance strain gage 补偿片compensation technique 补偿技术compensation technique 基准电桥reference bridge电阻应变计resistance strain gage 温度自补偿应变计self-temperaturecompensating gage半导体应变计semiconductor strainGage 集流器slip ring应变放大镜strain amplifier疲劳寿命计fatigue life gage电感应变计inductance [strain] gage 光[测]力学Photomechanics 光弹性Photoelasticity光塑性Photoplasticity杨氏条纹Young fringe双折射效应birefrigent effect 等位移线contour of equalDisplacement 暗条纹dark fringe条纹倍增fringe multiplication 干涉条纹interference fringe 等差线Isochromatic等倾线Isoclinic等和线isopachic应力光学定律stress- optic law主应力迹线Isostatic 亮条纹light fringe光程差optical path difference 热光弹性photo-thermo -elasticity 光弹性贴片法photoelastic coatingMethod光弹性夹片法photoelastic sandwichMethod动态光弹性dynamic photo-elasticity 空间滤波spatial filtering空间频率spatial frequency起偏镜Polarizer反射式光弹性仪reflection polariscope残余双折射效应residual birefringentEffect应变条纹值strain fringe value应变光学灵敏度strain-optic sensitivity 应力冻结效应stress freezing effect应力条纹值stress fringe value应力光图stress-optic pattern暂时双折射效应temporary birefringentEffect脉冲全息法pulsed holography透射式光弹性仪transmission polariscope 实时全息干涉法real-time holographicinterfero - metry 网格法grid method全息光弹性法holo-photoelasticity 全息图Hologram全息照相Holograph全息干涉法holographic interferometry 全息云纹法holographic moire technique 全息术Holography全场分析法whole-field analysis散斑干涉法speckle interferometry 散斑Speckle错位散斑干涉法speckle-shearinginterferometry, shearography 散斑图Specklegram白光散斑法white-light speckle method 云纹干涉法moire interferometry [叠栅]云纹moire fringe[叠栅]云纹法moire method 云纹图moire pattern 离面云纹法off-plane moire method 参考栅reference grating试件栅specimen grating分析栅analyzer grating面内云纹法in-plane moire method脆性涂层法brittle-coating method 条带法strip coating method坐标变换transformation ofCoordinates计算结构力学computational structuralmecha-nics加权残量法weighted residual method 有限差分法finite difference method 有限[单]元法finite element method 配点法point collocation里茨法Ritz method广义变分原理generalized variationalPrinciple 最小二乘法least square method胡[海昌]一鹫津原理Hu-Washizu principle赫林格-赖斯纳原理Hellinger-ReissnerPrinciple 修正变分原理modified variationalPrinciple 约束变分原理constrained variationalPrinciple 混合法mixed method杂交法hybrid method边界解法boundary solution method 有限条法finite strip method半解析法semi-analytical method协调元conforming element非协调元non-conforming element混合元mixed element杂交元hybrid element边界元boundary element 强迫边界条件forced boundary condition 自然边界条件natural boundary condition 离散化Discretization离散系统discrete system连续问题continuous problem广义位移generalized displacement 广义载荷generalized load广义应变generalized strain广义应力generalized stress界面变量interface variable 节点node, nodal point[单]元Element角节点corner node边节点mid-side node内节点internal node无节点变量nodeless variable 杆元bar element桁架杆元truss element 梁元beam element二维元two-dimensional element 一维元one-dimensional element 三维元three-dimensional element 轴对称元axisymmetric element 板元plate element壳元shell element厚板元thick plate element三角形元triangular element四边形元quadrilateral element 四面体元tetrahedral element 曲线元curved element二次元quadratic element线性元linear element三次元cubic element四次元quartic element等参[数]元isoparametric element超参数元super-parametric element 亚参数元sub-parametric element节点数可变元variable-number-node element 拉格朗日元Lagrange element拉格朗日族Lagrange family巧凑边点元serendipity element巧凑边点族serendipity family 无限元infinite element单元分析element analysis单元特性element characteristics 刚度矩阵stiffness matrix几何矩阵geometric matrix等效节点力equivalent nodal force 节点位移nodal displacement节点载荷nodal load位移矢量displacement vector载荷矢量load vector质量矩阵mass matrix集总质量矩阵lumped mass matrix相容质量矩阵consistent mass matrix 阻尼矩阵damping matrix瑞利阻尼Rayleigh damping刚度矩阵的组集assembly of stiffnessMatrices载荷矢量的组集consistent mass matrix质量矩阵的组集assembly of mass matrices 单元的组集assembly of elements局部坐标系local coordinate system局部坐标local coordinate面积坐标area coordinates体积坐标volume coordinates曲线坐标curvilinear coordinates 静凝聚static condensation合同变换contragradient transformation 形状函数shape function试探函数trial function检验函数test function权函数weight function样条函数spline function代用函数substitute function降阶积分reduced integration零能模式zero-energy modeP收敛p-convergenceH收敛h-convergence掺混插值blended interpolation等参数映射isoparametric mapping双线性插值bilinear interpolation小块检验patch test非协调模式incompatible mode 节点号node number单元号element number带宽band width带状矩阵banded matrix变带状矩阵profile matrix带宽最小化minimization of band width 波前法frontal method子空间迭代法subspace iteration method 行列式搜索法determinant search method 逐步法step-by-step method 纽马克法Newmark威尔逊法Wilson拟牛顿法quasi-Newton method牛顿-拉弗森法Newton-Raphson method 增量法incremental method初应变initial strain初应力initial stress切线刚度矩阵tangent stiffness matrix 割线刚度矩阵secant stiffness matrix 模态叠加法mode superposition method 平衡迭代equilibrium iteration子结构Substructure子结构法substructure technique 超单元super-element网格生成mesh generation结构分析程序structural analysis program 前处理pre-processing后处理post-processing网格细化mesh refinement应力光顺stress smoothing组合结构composite structure。

第7章应力腐蚀和氢脆断裂

12
二、应力腐蚀断裂机理及断口形貌特征
13
应力腐蚀断裂机理
应力腐蚀断裂最基本机理：是滑移－溶解理论(或称钝化膜破坏理论)和氢脆理论。
对应力腐蚀敏感的合金在特定化学介质中，（1）表面先形成一层钝化膜，使金属不致进一步受到腐蚀，
即处于钝化态。若无应力作用，金属不会发生腐蚀破坏。
（2）若有拉应力作用，则可使裂纹尖端产生局部塑性变形，滑移台阶在表面露头时钝化膜破裂，显露出新鲜表面。
1
2
第一章应力腐蚀和氢脆断裂
3
第一节应力腐蚀
4
金属机件在加工过程中常会产生残余应力，在服役过程中又承受外加载荷，同时又与周围环境中各种化学介质或氢相接触，便会产个特殊的断裂现象，这就有应力腐蚀断裂和氢脆断裂等。
这些断裂形式大多为低应力脆断，具有很大的危险性。
随着航空航天、海洋、原子能发电、石油、化工等工业的迅速发展，对金属材料强度的要求越来越高，接触的化学介质的条件越加苛刻，致使上述各种断裂形式逐年增多。
（原来存在或从环境介质中吸收），在低于屈服强度的应力持续作用下，经过一段时间（孕育）后，在金属内部，特别在三向拉应力区形成裂纹，裂纹逐步扩展，最后突然发生脆性断裂。
这种因氢的作用而产生的延迟断裂称为“氢致延迟断裂”。工程上所说“氢脆”：大多数是指这类氢脆。
32
氢致延滞断裂特点
氢致延滞断裂特点： 1）只在一定温度范围内出现；如高强度钢多在－100～ 150℃间，而以室温下最敏感。
若裂纹尖端应力集中始终存在，则微电池反应便不断进行，钝化膜不能恢复，裂纹将逐步向纵深扩展。
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应力腐蚀断裂机理
应力腐蚀过程，衡量腐蚀速度的腐蚀电流I 可表示为：

GB《压力容器通用要求》新GB宣贯教材

第十一页，共七十七页。
GB150.1《压力容器通用要求》
3.2.2 标准所考虑的失效模式失效模式与设计规范中所考虑的设计载荷和使用
工况有密切的联系，表1给出了世界各国标准中所考虑的载荷条件对比分析：
第十二页，共七十七页。
GB150.1《压力容器通用要求》
(1)以失效模式为依据的设计方法
ISO 16528[5]综合世界主要工业国家的技术标准规定，参照欧洲标准的内容，针对锅炉和压力容器常见的失效形式，在标准中将其归为三大类、 14种失效模式，明确了针对失效模式的设计技术应用理念。
第十五页，共七十七页。
GB150.1《压力容器通用要求》
第三大类：循环失效模式(Cyclic failure modes)： ● 扩展性塑性变形Progressive plastic deformation； ● 交替塑性Alternating plasticity； ● 弹性应变疲劳(中周和高周疲劳)或弹-塑性应变疲劳 (低周疲劳) Fatigue under elastic strains
第二十页，共七十七页。
GB150.1《压力容器通用要求》
强度理论
在实际工程应用中主要有以下几个典型的强度理论:
第一强度理论：基于该理论的强度条件可表示为： σ1≤ [σ]
第二强度理论：又称最大拉应变理论：
第三强度理论：又称最大剪应力理论。强度条件即为： σ1-σ3 ≤[σ]目前我国的JB 4732标准，2007年以前的ASME、Ⅷ—div2篇等
● 蠕变失稳(Creep instability) ● 冲蚀、腐蚀(Erosion，corrosion)；
● 环境助长开裂如：应力腐蚀开裂、氢致开裂(Environmentally assisted cracking e.g. stress corrosion cracking，hydrogen induc cracking，etc)。

Chapter 4-corrosion under stress

4
一、应力腐蚀断裂的特征
具备三条件：敏感材料，特定环境和拉伸应力。如锅炉钢在碱液中的“碱脆”；低碳钢在硝酸盐中的“硝脆”，奥氏体不锈钢在含氯离子液中的“氯脆”；黄铜在氨气中的“氨脆”。
5
敏感材料
certain alloys从金到钛、锆，几乎所有金属的合金在特定环境中都有某种应力腐蚀敏感性。纯金属不会发生应力腐蚀开裂。 99.99%Fe在硝酸盐溶液中难以开裂，含0.04%C 即可发生硝脆。
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二、应力腐蚀开裂的特征
1.典型的滞后破坏
2.裂纹分为晶间型、穿晶型和混合型
3.裂纹扩展速度比均匀腐蚀快约106倍 4.SCC开裂是一种低应力的脆性断裂
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1.SCC是典型的滞后破坏
应力腐蚀断裂是一种典型的滞后破坏，需经一定时间的裂纹形核、裂纹亚临界扩展，最终达到临界尺寸，发生失稳断裂。存在一个孕育期90％（裂纹成核），裂纹扩展期（成核到临界尺寸），快速断裂期。
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特定介质
某种合金的应力腐蚀开裂只是对特定介质敏感。通常合金对引起应力腐蚀的环境是惰性的，表面往往存在钝化膜。这种特定的环境并不要大量存在才造成应力腐蚀。如空气中少量的氨气，甚至鼻子感觉不出就会造成黄铜的氨脆。材料与环境的交互作用反映在电位上就是SCC 一般发生在活化－钝化或钝化－过钝化的过渡区电位范围，即钝化膜不完整的电位区间
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Chloride Attack: Waste water with a high chloride content caused rapid corrosion of this stainless steel mixing valve.
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Ammonia Attack :A few parts per million of ammonia in boiler feed water caused failure of this bronze valve.

武汉理工大学研究生--材料科技英语-课文翻译

GlassIt is well known that glasses play an important role as one of building materials ordinary living products. Advanced and specialty glasses also play important roles in several industries. In the last several years, these materialshave continued to find new applications in the areas of telecommunications, electronics, and biomedical uses. Glass compositions and processing techniques continue to evolve to suit the increasing number of applications. Some of the glass compositions have distinctive properties that make them the most preferred materials for certain applications, such as optical fibers, electronic displays, biocompatible implants, dental posterior materials, and high-performance composites.众所周知，玻璃作为建筑材料普通生活产品之一起着重要的作用。

先进和特种玻璃也在许多行业也起着重要作用。

在过去几年中，这些材料继续在电讯，电子，生物医学领域发现新的应用。

为适应日益剧增的应用，玻璃的组分和加工技术不断发展。

Stress corrosion cracking behavior of 310S in supe

Stress corrosion cracking behavior of 310S in supercritical water with different oxygen concentrationsJin-Hua Liu 1,2•Yue-Ming Tan 2•Yuan Wang 1•Bin Gong 2•Er Jiang 2•Yong-Fu Zhao 2•Jia-Zhen Wang 2•Shan-Xiu Cong 2Received:6July 2017/Revised:6September 2017/Accepted:7September 2017ÓShanghai Institute of Applied Physics,Chinese Academy of Sciences,Chinese Nuclear Society,Science Press China and Springer Nature Singapore Pte Ltd.2018Abstract The effect of dissolved oxygen (DO)on the stress corrosion cracking (SCC)of 310S in supercritical water was investigated using slow-strain-rate tensile tests.The tensile properties,fracture morphology,and distribu-tion of the chemical composition of the oxide were ana-lyzed to evaluate the SCC susceptibility of 310S.The results showed that the rupture elongation decreased sig-niﬁcantly as the degree of DO increased.A brittle fracture mode was observed on the fracture surface,and only intergranular cracking was observed on the surface of the gauge section,regardless of the DO.Cracks were widely distributed on the gauge surface near the fracture surface.Oxides were observed in the cracks with two-layered structures,i.e.,a Cr-rich inner oxide layer and an Fe-rich outer oxide layer.Keywords Supercritical water ÁDissolved oxygen ÁStress corrosion cracking ÁAustenitic stainless steels ÁEPMA1IntroductionA supercritical water reactor (SCWR)is considered a promising Generation IV nuclear reactor owing to its simple design and high thermal efﬁciency.An SCWR is a high-temperature,high-pressure,and water-cooled reactor,which operates above the critical point of water (374°C,22.1MPa)[1–4].The typical design of an SCWR is a once-through,direct-cycle system operating at a pressure of 25MPa and temperature range from 280to 620°C [5–7].One of the major problems faced by SCWRs is the lack of data related to the material behavior of supercritical water (SCW).The resistance to corrosion and stress cor-rosion cracking (SCC)under SCW conditions are impor-tant requirements [8,9].It is well known that SCW is highly corrosive to metallic materials,especially in an oxidizing environment,and the fuel cladding in an SCWR is likely to be subjected to severe corrosion.Therefore,selecting appropriate candidate materials for fuel cladding is an important feature of SCWR design [10].In addition,SCC is one of the major concerns in the selection of materials and is still an important technical issue [11–16].Austenitic stainless steels have been widely used as structural materials in nuclear reactors owing to their excellent high-temperature corrosion resistance and good mechanical properties [17–19].Typical 310S stainless steel is considered a promising material for fuel cladding of the Chinese CSR1000[20]and the Japanese SCWR design [2].Owing to the radiation effect,there is an elevated dissolved oxygen (DO)concentration.It is generally known that the SCC behavior of stainless steel is subject to water chem-istry such as oxygen.However,many corrosion studies have been conducted in low DO or deaerated environments [21,22].There are few studies on the SCC susceptibility ofThis work was supported by the National Natural Science Foundation of China (Nos.51271171and 11775150).&Yuan Wangwyuan@ &Bin Gonggongbin_npic@1Key Laboratory of Radiation Physics and Technology,Ministry of Education,Institute of Nuclear Science and Technology,Sichuan University,Chengdu 610065,China 2Nuclear Power Institute of China,Chengdu 610041,ChinaNUCL SCI TECH (2018) 29:76https:///10.1007/s41365-018-0405-1310S with different DO concentrations in SCW.Therefore, a thorough understanding of the SCC behavior of310S in SCW with different DO concentrations is signiﬁcant for the development of SCWRs.Therefore,in this study,the effect of DO on the SCC susceptibility of310S was studied by carrying out slow-strain-rate tensile(SSRT)tests.2Experimental2.1MaterialsThe materials used in this work were extruded bars of 310S austenitic stainless steels(Pang Steel Corporation). The extruded bars were subjected to solution heat treatment at1050°C for1h,followed by quenching in water.The chemical composition of310S is listed in Table1.The specimens for the SCC test were sampled from the extru-ded bar parallel to the loading direction along the rolling direction and processed into a round bar with a gauge of length20mm and diameter 4.0mm according to the ASTM standard E8.The geometry of the round bar tensile specimen is shown in Fig.1.The gauge section was bur-nished with1000grit emery paper,washed with ethanol in an ultrasonic cleaner,and cleaned with distilled water.The polishing direction was parallel to the loading direction.2.2CharacterizationTo investigate the SCC susceptibility of310S in SCW, SSRT tests were performed on specimens in a supercritical environment corrosion testing facility,as shown in Fig.2, which can be operated at a temperature up to650°C at the pressure of30MPa.The loading rate of the testing facility can be continuously adjusted from0.0001to1mm s-1. There are two loop systems in the testing facility,one each for establishing speciﬁc SCW environments and monitor-ing water chemistry at room temperature(25°C).Deion-ized water with conductivity less than0.1l S/cm was pressurized to25MPa and heated to620°C to establish the SCW environment.The volume of the autoclave was 2.5L and theﬂow rate of inlet water could reach up to 15L/h,yielding an autoclave water refreshment rate of approximately6times per hour.A stable and reliable water chemistry environment was obtained during the testing.The DO concentration was measured directly on the equipment using an Orbisphere oxygen analyzer.The DO concentration in the SCW environment during the SCC tests ranged from zero to8000ppb with continuously bubbling argon–oxygen mixture gases.The strain rate of the specimen was maintained at7.5910-7s-1in this work,which has been shown to be appropriate to evaluate the SCC susceptibility of stainless steel at high tempera-tures[6].After the test,the stress–strain curves,fracture mor-phology,and chemical composition of the oxide were analyzed to evaluate the SCC susceptibility and mechanical properties of310S.The analysis of fractographic features of the specimens was conducted using aﬁeld-emission scanning electron microscope(FE-SEM JSM-7500,Japan), and an energy-dispersive X-ray spectroscopy(EDS)model OX-FORD IE-250attached to the SEM was utilized to analyze the chemical composition of the oxide layer.The electron probe microanalyzer(EPMA-1720,Japan)analy-sis was also used to study the distribution of the major elements in cracks on the cross section along the gauge section.3Results and discussion3.1Stress–strain curvesThe stress–strain curves of310S obtained from the SSRT tests in SCW at620°C are shown in Fig.3and the results are presented in Table2.Elongation reduction can be used as a quantitative method to evaluate the SCC susceptibility.The elongation of310S decreased with the increase in DO concentration,which indicates its depen-dence on DO concentration.The elongation under different DO conditions ranged from36.7to45.6%.Compared with the data measured in the deaerated SCW,the elongation was decreased by19.5%when DO reached8000ppb.This tendency follows the increase in the oxidation potential of SCW.According to Zhu[23],DO changes theoxidation Fig.1Dimensions of the tensile specimen(mm)Table1Chemical composition(wt%)of the310S stainless steelC Si Mn S P Cr Ni Fe0.0420.450.950.0020.02524.4220.34Bal.76 Page2of7J.-H.Liu et al.potential of SCW,leading to an increase in the oxidation rate.Lu [24]investigated the effect of DO on the SCC of 316NG in simulated boiling water reactor environments using a different technique.His study indicated that the potential gradient between the crack mouth and crack tip increases with the increase in DO concentration in high-temperature water,and the crack growth rate increases with the increase in DO owing to the acceleration of the oxi-dation rate at the crack tip.A similar result was also obtained by Zhang [25].The crack growth rate of 316L increases with the increase in DO concentration in the simulated pressurized water reactor primary water,as DO may affect the oxide ﬁlm structure.DO has a negligible effect on both the ultimate tensile strength (UTS)and yield strength (YS).The insensitivity of UTS and YS to DO is consistent with the literature data on 316Ti stainless steel tested at the temperature of 650°C [17].Fig.2Flowchart of the supercritical environment corrosion testing facility.1feed water pump,2high-pressure circulating pump,3pressure balancing tank,4preheater,5heat exchanger,6test section,7tensile strain test system,8water cooler,9compression releasevalve,10outlet water storage tank,11volume pump for measuring system,12liquid puriﬁcation column,13test solution storage tank,14compressed gas cylinders,15chemical feedpumpFig.3(Color online)Stress–strain curves of SSRT tests of 310S in SCW with different DO concentrationsTable 2Results of measurement and key parametersDO (ppb)UTS (MPa)YS (MPa)Elongation (%)Fracture mode 022918645.6Brittle,IG 50022517044.7Brittle,IG 100023418439.8Brittle,IG 200022917438.9Brittle,IG 800023319036.7Brittle,IGStress corrosion cracking behavior of 310S in supercritical water with different oxygen …Page 3of 7763.2Fracture behavior3.2.1Fracture morphology analysisThe SEM analysis of broken specimens was used to characterize the fracture behavior.Figure 4a shows the SEM image of the fracture surface of 310S tensile strained in deaerated SCW.The failure surface of 310S exhibited brittle and intergranular morphology.Almost all the spec-imens were covered with grains.Intergranular facets appeared in both the center and edge regions of the fracture surface,which are characteristics of brittle fracture,as shown in Fig.4b,c.These results are very close to the data of HR3C,tested in SCW at temperatures of 600and 650°C [26].The specimens tested in SCW with different DO concentrations showed similar characteristics,suggesting that DO has no signiﬁcant effect on the fracture surface morphology.3.2.2Gauge surface morphology analysisMicrographs of the gauge surfaces showed similar characteristics after SCW tests with different DO concen-trations at 620°C.Figure 5shows that the cracks on 310S were widely distributed at the gauge surface near the fracture surface,and most of the cracks were perpendicular to the loading direction.By using EDS to analyze the oxide ﬁlm on the gauge surface,chemical changes were observed in the oxide ﬁlm formed in the SCW with different DO concentrations,as presented in Table 3.The detected oxide ﬁlm was located at the gauge surface close to the crack mouth (see label 1in Fig.5).The EDS results show that the oxide layer was mainly composed of Cr,O,and Fe,and the Cr concentration increased with the increase in DO.Numerous studies on austenitic stainless steel have shown that the oxides have a two-layered structure [7,27,28].The inner layer is rich in chromium,and the outer layer is mainly composed of magnetite.According to Was [7],forFig.4Fracture surfaces of specimens tested at 620°C with DO at 0ppb;position A is in the center region and position B is in the edge region of the fracturesurfaceFig.5(Color online)SEM images of 310S tested in SCW at 620°C with DO at 500ppb76 Page 4of 7J.-H.Liu et al.most high nickel–chromium stainless steels,the outer oxide layer loosely adheres to the inner layer and exhibits a tendency to spall.Similar results can be found in Ref.[29].Furthermore,the DO affects the structure and composition of the oxide layer formed on stainless steel.At a high DO concentration,the incorporation of chromium into the oxide layer is promoted,inhibiting the formation of mag-netite at the top of the oxide layer [22].When oxygen is present,the solvation and oxidation of SCW are enhanced.The solubility of Fe-rich outer oxides is likely to increase,leading to the decrease in the concentration of iron oxidewith the increase in DO and the opposite trend for Cr concentration.3.2.3Cross-sectional analysisEPMA analysis was performed on the cross sections of fractured specimens to investigate the relationship between a crack and oxide layer.Figure 6a,b shows the results obtained from EPMA using a wavelength-dispersive spectrometer (EPMA–WDS)on the cross section of the specimens.The Fe–Cr oxide was distributed along the crack,and the oxide ﬁlm can be divided into two layers.The outer oxide layer was rich in Fe,whereas the inner oxide layer was rich in Cr.This observation of a double oxide layer is consistent with the studies on 316austenitic stainless steel in SCW [26,27].It is speculated that dif-fusion plays a key role in the formation of the double oxide layer.Oxygen diffused inward,whereas metal elements such as Cr and Fe diffused outward.The iron was enriched in the outer layer but was depleted in the inner layer,whereas the concentration of chromium exhibited the opposite trend.These differences in the distribution of iron and chromium may be due to a lower diffusion rate ofTable 3Results of EDS of oxide on specimen surfaces at different DO concentrations in SCW DO (ppb)Time to fracture (h)Cr (wt%)Fe (wt%)O (wt%)01697.5562.2230.2250016512.8256.8430.34100014716.6052.8330.36200014440.2828.7730.95800013363.914.6131.48Fig.6(Color online)EPMA analysis results of 310S specimens after testing in a ,c deaerated SCW and b ,d SCW with DO of 8000ppbStress corrosion cracking behavior of 310S in supercritical water with different oxygen …Page 5of 776chromium in the oxide layer compared with that of iron.It is believed that an inner layer was formed on the original surface of the polished specimen,and the oxide was grown via selective oxidation and diffusion of chromium.The iron ions diffused outward to form an outer oxide layer,whereas fewer chromium ions are transferred to the outer oxide layer owing to the low diffusion rate.Ni enrichment was detected at the oxide/metal interface,which can be explained by the low diffusion and incorporation rate of nickel in the oxide layer[30].This phenomenon has also been observed by Behnamian[31],who attributed the formation of Cr-rich oxide to selective oxidation.The oxide layer formed in SCW with DO of8000ppb has an approximate thickness of10l m,and the oxide layer formed in the deaerated SCW has an approximate thickness of17l m.The oxide layer formed in the SCW with DO of 8000ppb is thicker than that in the deaerated water,indi-cating an accelerated corrosion effect caused by oxygen.It is well known that chromium oxide is a passiveﬁlm and can mitigate corrosion effectively.Therefore,the integrity of the Cr-rich inner oxide layer may play an important role in the SCC resistance of tensile specimens in deaerated SCW and SCW with DO of8000ppb.Figure6c, d shows the cross-sectional images of the tensile specimens after SSRT in deaerated SCW and SCW with DO of 8000ppb,obtained using EPMA with an EDS(EPMA-EDS).Notably,the distribution of Cr-rich oxide layer along the crack changes with the oxygen concentration.For the specimen exposed to deaerated SCW,the Cr-rich oxide layer appears to be compact and has no discontinuity,as shown in Fig.6c.In SCW with DO of8000ppb,the Cr-rich oxide layer in Fig.6d is relatively discontinuous at some locations,and the thickness of Cr-rich oxide layer is non-uniform.As shown in the morphology,the thickness of Cr-rich layer increases,particularly in the region of the cracks near the surface of the specimens.The thicker Cr-rich oxide layer can lead to higher internal stress in the oxideﬁlm,resulting in a higher risk of breaking of the oxideﬁlm in SCW with DO of8000ppb.It is expected that a thin and continuous Cr-rich oxide layer prevents further oxidation,whereas the discontinuous Cr-rich oxide layer may increase the SCC susceptibility.Notably,only the inner oxide layer is detected in the region of the cracks near the surface,which can be attributed to the dissolution of the outer oxide layer or spallation caused by the internal stress inside the oxide layer.It is consistent with the EDS results presented in Table3.4ConclusionSSRT tests of310S were carried out in SCW at a tem-perature of620°C,pressure of25MPa,and strain rate of 7.5910-7s-1.The tests were performed with DO con-centrations of0,500,1000,2000,and8000ppb.Accord-ing to the above experiments,the main results are as follows:1.DO in the SSRT test had a negligible effect on YS andUTS,whereas the elongation was strongly dependent on the DO concentration.2.A brittle fracture mode was observed on the fracturesurface,and dense cracks were observed on the gauge section.The entirely brittle character and a similar fracture surface indicate that the effect of DO on the fracture morphology is negligible.3.Oxides were observed inside the cracks with two-layered structures:an Fe-rich outer oxide layer and a Cr-rich inner oxide layer.The Cr-rich inner oxide layer inside the cracks was more continuous in deaerated SCW compared with that in oxygenated SCW. 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STRESS CORROSION CRACKING TEST METHOD FOR ALCOHOL

专利名称：STRESS CORROSION CRACKING TESTMETHOD FOR ALCOHOL ENVIRONMENTS 发明人：SAMUSAWA, Itaru,寒沢　至,SHIOTANI,Kazuhiko,塩谷　和彦申请号：JP2015/000801申请日：20150219公开号：WO2015/129215A1公开日：20150903专利内容由知识产权出版社提供专利附图：摘要：Provided is an SCC test method whereby an SCC environment in bio-alcohol can be simulated in a laboratory and a steel material in a bio-alcohol environment can beevaluated in a short time. The stress corrosion cracking test method for alcohol environments is a test whereby the stress corrosion cracking susceptibility of a steel material in alcohol is evaluated, said method being characterized by: cells covering a uniaxial tensile test piece of the steel material being filled with an alcohol solution including at least 0.1 mmol/L but less than 40 mmol/L carboxylic acid, at least 0.05 mg/L but less than 300 mg/L chloride ions, and at least 0.1 vol.% but less than 5 vol.% water; and applying, in the tensile axis direction of the uniaxial tensile test piece and at a frequency of 2.0 × 10-2.0 × 10 Hz, a fluctuating stress to the uniaxial tensile test piece, said fluctuating stress having a maximum stress of at least the yield point at the test solution temperature but less than the tensile strength and a minimum stress of 0%-90% of said yield point.申请人：JFE STEEL CORPORATION,ＪＦＥスチール株式会社地址：〒1000011 JP,〒1000011 JP国籍：JP,JP代理人：KUMASAKA, Akira et al.,熊坂　晃更多信息请下载全文后查看。

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Table I.Chemical Compositions (Weight Percent)of the7475Aluminum Alloy Alloy Zn Mg Cu Cr Fe Si Mn Ti Al 74755.802.241.530.190.080.020.010.02balFig.1—Three-dimensional micrograph showing grain structure of the as-received 7475alloy plate.Table II.Postforming Heat-Treatment Procedures of the Superplastically Formed Workpieces*Temper ConditionAging TreatmentT6near peakaged 24h/120ЊCRRA peakaged T6aged ϩ5min/220ЊC ϩT6aged T73overaged6h/107ЊC ϩ24h/163ЊC*Solution treated at 515ЊC for 1.5h ϩwater quenched.Table III.Cavitation Volume Fraction of SuperplasticallyFormed Workpieces with Various ETS*ETS ϭ20Pct ETS ϭ50Pct ETS ϭ100PctCavitation 0.07ע0.020.14ע0.020.19ע0.03⌬V /V (Pct)*Data indicate mean ע1standard deviation.Table II.All tempered conditions for the different extents of superplastic deformation in this study are shown in Table III.Rectangular tensile specimens with longitudinal direc-tion,cut through the central section of the pan bottom,for each tempered condition were used to measure mechanical properties and aqueous SCC resistances.The tensile spec-imens were milled to 25-mm gage length,6-mm width,and 1-mm thickness.Tensile tests were performed at a strain rate of 10Ϫ3s Ϫ1in air to obtain 0.2pct offset yield strength,tensile strength,and elongation.The SCC tests were eval-uated by using a slow strain rate test (SSRT).[19]The SSRT has the advantage that it will promote SCC in systems that in static tests either do not crack or take a particularly long time to show evidence of failure.The specimens of SSRT were tested at a strain rate of 4ϫ10Ϫ6s Ϫ1in air and in near-neutral 3.5pct NaCl aqueous solution (pH ϭ6.8),respectively.The SCC susceptibility for all tempered con-ditions could be evaluated by means of comparing their elongation losses,which were calculated by the elongations of testing in air,and those of testing in 3.5pct NaCl so-lution.The specimen,cut from the central section of the pan bottom,for each tempered condition was employed to mea-sure the electrochemical properties by using a potentio-dynamic polarization technique.Each specimen was polished with abrasive paper to 600grit,then rinsed in ac-etone and washed in distilled water.The surface area of the working electrode was 25mm 2.The potentiodynamic po-larization tests were conducted in a cell containing aerated 3.5pct NaCl solution (same as the aqueous SCC testingenvironment)at room temperature.This cell was equipped with a saturated calomel reference electrode and a platinum auxiliary electrode.Before polarization tests,the specimens were cathodically polarized at a constant potential of Ϫ1500mV for 5minutes to clean the electrode surface.Then,potentiodynamic scanning at a rate of 1mV/s,from cathodic toward anodic direction,was applied to obtain the polarization curves.The extent of cavitation for the pan-shaped workpiece was quantitatively evaluated by comparing the density loss with unformed material.At least ﬁve samples for each forming height workpiece,from the central to the corner section of the pan bottom,were cut to measure the ing a suspended ﬂotation technique,the specimen densities were measured by comparison with an equal den-sity mixture of two organic liquids (diiodomethane and io-doethane).[5,20]The densities of mixtures were obtained by pycnometry.[21]All testing specimens were treated by T6temper before measuring densities to avoid the inﬂuence of different heat-treatment procedures.[5,20]A JEOL 100CXII transmission electron microscope op-erating at 100kV was utilized to observe the microstruc-tural change.Thin foils were prepared by twin-jet electropolishing in a 33pct HNO 3ϩ67pct methanol so-lution cooled to Ϫ25ЊC,using a potential of ϳ12V.Frac-tography of the SCC and corrosion testing specimens was conducted with a PHILIPS*SEM515scanning electron mi-*PHILIPS is a trademark of Philips Electronic Instruments Corp.,Mahwah,NJ.croscope operating at 20kV.III.RESULTSThe typical pan-shaped workpieces with the different forming heights and their central cross-sectional proﬁles are shown in Figures 2(a)and (b),respectively.Figure 2(b)indicates that the forming thicknesses of the pan-shaped specimens are decreased with increasing the forming height,and their thickness distributions are not uniform.The amount of superplastic strain for each pan-shaped workpiece was evaluated as an equivalent tensile strain (ETS)by using the following relationship:[18]ETS pct ϭ(t 0/t f Ϫ1)ϫ100Fig.2—(a )The pan-shaped specimens with the different forming heights.(b )The central cross-sectional proﬁles of the pan-shapedspecimens.Fig.3—The typical cavitation distributions around the central section of the bottom of the pan-shaped specimens for the different forming heights.(a )through (c )The forming heights are equal to (a)1cm,(b)2cm,and (c)3cm.where t 0is the thickness of the plate before forming (2mm),and t f is the thickness of the plate after forming.The average forming thickness of the workpiece bottom was used to calculate the ETS in this study.The approxi-mate ETS for the different forming heights with 1,2,and 3cm are 20,50,and 100pct,respectively.Figure 3shows the cavitation distributions around the central section of the pan bottom for the different forming height workpieces.It can be found that the cavitations almost nucleated at grain boundaries,and the larger and more evident cavitations in-creased with increasing the forming height,as indicated in Figure 3.The cavitation volume fractions for the various extents of superplastic deformation are shown in Table III.It demonstrates that the cavitation is increased with increas-ing the amount of ETS.Before and after all postforming heat treatments,the me-chanical properties of the pan-shaped specimens with dif-ferent ETSs are shown in Table IV.The following points should be noted from Table IV:(1)The yield strengths of the pan-shaped workpieces without any postforming temper were lower than 200MPa.After postforming temper,the strengths of the pan-shaped samples could largely be increased to higher than 400MPa.These results demonstrate that the superplastically formedworkpieces can only be applied after the post-forming tem-pered treatment.(2)The postforming RRA temper produced the highest yield strength and the smallest elongation for the same ex-tent of superplastic deformation,which showed the peak-Table IV.Mechanical and Stress-Corrosion Properties of Superplastically Formed Workpieces With Various EquivalentTensile Strain Temper*UTS**(MPa)0.2YS**(MPa)El.**(Pct)El.Air †(Pct)0.2YS Sol.‡(MPa)El.Sol.**(Pct)El.Sol.loss §(Pct)1-AC 413.4199.810.1————2-AC 406.8192.49.5————3-AC 349.2139.88.8————0-T6559.4502.413.815.1480.5 6.656.31-T6551.7490.711.512.8474.7 5.259.42-T6545.9482.09.710.8469.8 4.063.03-T6538.9473.68.69.3272.3 2.474.20-RRA 562.4516.710.511.3509.110.48.01-RRA 557.6511.29.210.1506.49.19.92-RRA 549.3505.17.98.5496.17.314.13-RRA 540.8497.2 6.87.3481.5 5.623.30-T73510.4455.510.912.0450.311.2 6.61-T73506.7453.69.810.8448.910.07.42-T73500.9450.38.08.8445.17.910.23-T73491.1443.87.48.0431.26.716.3*0,1,2,and 3represent the forming height of the pan-shaped workpieces (units:cm);AC represents superplastic forming,then air cooling;and T6,RRA,and T73represent AC specimens,then postforming T6,RRA,and T73temper,respectively.**Tensile test at a strain rate of ε⅐ϭ10Ϫ3/s in air.†Tensile test at a strain rate of ε⅐ϭ4ϫ10Ϫ6/s in air.‡Tensile test at a strain rate of ε⅐ϭ4ϫ10Ϫ6/s in 3.5pct NaCl solution.§El.Sol.loss ϭ1Ϫ(El.Sol.**/El.Air †).Fig.4—Stress-displacement curves of the slow strain rate tests for various extents of superplastic deformation with different postforming heat treatments.(Each of the tempered conditions is the same as given in the footnote of Table IV.)aged properties.The postforming T6and postforming T73tempers indicated a near peakaged and an overaged con-dition,respectively.On the other hand,the mechanical properties were decreased with increasing the ETS for each postforming heat treatment.The inﬂuence of ETS on the decay of mechanical properties could be found to be de-creased from postforming T6,RRA to T73tempered con-dition.(3)Under the same postforming T6tempered treatment,comparing the mechanical properties of the pan-shaped specimen possessing the ETS of about 100pct (3-T6)with those of the unformed condition (0-T6),the losses of the yield strength and elongation are 6and 38pct,respectively.This result indicates that the effect of the superplastic form-ing on the decay of elongation is larger than that on the decay of yield strength.The stress-displacement curves of SSRT in 3.5pct NaCl solution for all tempered conditions are shown in Figure 4.Generally,if the value of displacement is larger,it means that the SCC resistance of the alloy is better.[22]The elon-gation losses for all tempered conditions are also given in Table IV.From Figure 4and Table IV,the following points should be noted:(1)The mechanical properties,tested in 3.5pct NaCl solution,were decreased with increasing the amount of superplastic deformation for each postforming heat treatment.However,the effect of superplastic defor-mation on the decay of elongation is still larger than that on the decay of strength.On the other hand,the SCC sus-ceptibility,comparing the elongation loss,was also in-creased with increasing the ETS under the same postforming tempered condition.(2)Under the same ETS condition,the SCC susceptibility was the most severe for postforming T6temper,intermediate for postforming RRA temper,and minimal for postforming T73temper.It indi-cates that the postforming RRA temper could effectively improve the SCC resistance of postforming T6temper and did not sacriﬁce its mechanical strength.(3)The values ofdisplacement were in proportion to the values of elongation loss for all tempered conditions.These proportional rela-tionships proved that the relative SCC susceptibility for all tempers could be directly obtained by comparing the values of displacement of each heat treatment.The polarization curves for different postforming heat treatments are shown in Figure 5.The electrochemical data,including corrosion potential,pitting potential,corrosion current density,and passive current density,for all tem-pered conditions are indicated in Table V.The following points should be noted from Figure 5and Table V:(1)Under the same postforming heat treatment,increasing the extent of ETS caused both the corrosion potential and the pitting potential to become more anodic and both the cor-rosion current density and the passive current density to increase.(2)The corrosion potentials for the same amountFig.5—The polarization curves for various extents of superplastic deformation with different postforming heat treatments:(a)T6,(b)RRA, and(c)T73.of superplastic deformation were shifted to be more noble in the sequence of postforming T6,RRA,and T73tempered condition.However,the tendency of the pitting potential for all postforming tempers in the same ETS condition is converse to that of the corrosion potential.Therefore,the range of the passive potential for the same ETS condition was decreased from postforming T6,RRA to T73tem-pered.(3)Under the same ETS condition,the corrosion current density and the passive current density were de-creased from postforming T6,RRA to T73tempered.This means that the postforming T6temper would possess the best corrosion resistance under the same extent of super-plastic deformation.After the polarization test,the typically corroded mor-phologies of the superplastically formed specimens are shown in Figure6.Under the same postforming tempered condition,any obvious morphologic distinction could not be found for the different amounts of superplastic defor-mation.For the postforming T6tempered specimens,the corrosion morphologies showed that the nonuniform distri-butions of pits with fourfold symmetry on{001}planes were formed,as indicated in Figures6(a)and(b),respec-tively.[23]The corroded morphologies of the postforming RRA and T73tempered conditions are similar to that of the postforming T6tempered condition,as shown in Fig-ures6(c)through(f).However,the pitting area and the pile density of cubic pits are increased as the degree of aging is increased.It indicates that the postforming T73temper caused the most serious pitting corrosion for the same su-perplastic forming condition.The typical precipitate-free zone(PFZ)widths,grain boundary␩precipitates,and slip behaviors for the pan-shaped workpieces under various postforming tempered conditions are shown in Figure7.The PFZ width and the size of GBP were increased from postforming T6,RRA to T73temper.However,both the slip band spacing and the slip band length revealed the opposite tendency,as did the PFZ width.No obvious microstructural difference was found for the various ETS conditions that were treated by the same postforming tempered condition.Table V.Electrochemical Data of the Superplastically Formed Workpieces with Various Equivalent Tensile Strain Temper*␾corr **(V)␾p **(V)⌬␾**(V)i corr **(␮A/cm 2)i p **(␮A/cm 2)0-T6Ϫ1.166Ϫ0.7180.448 3.16 6.501-T6Ϫ1.189Ϫ0.7300.459 4.477.872-T6Ϫ1.196Ϫ0.7420.45410.0110.823-T6Ϫ1.198Ϫ0.7580.44017.7819.310-RRA Ϫ1.158Ϫ0.7260.432 4.897.861-RRA Ϫ1.180Ϫ0.7340.44611.039.882-RRA Ϫ1.182Ϫ0.7450.43715.9213.263-RRA Ϫ1.189Ϫ0.7580.43127.3819.820-T73Ϫ1.121Ϫ0.7350.386 5.618.511-T73Ϫ1.158Ϫ0.7410.41713.9610.462-T73Ϫ1.171Ϫ0.7520.41920.8514.133-T73Ϫ1.173Ϫ0.7600.41328.5120.17*See Table IV.**␾corr :corrosion potential;␾p :pitting potential;⌬␾:the range of the passive potential ϭ␾p Ϫ␾corr ;i corr :corrosion current density;and i p :passive current density.IV.DISCUSSIONAdding the Zn and Mg alloying elements to the alumi-num solid solution matrix will cause the corrosion potential of the aluminum alloy to become more anodic.[23,24]The concentration of Zn and Mg alloying elements in the matrix will be decreased with increasing the degree of aging be-cause of the precipitation of MgZn 2.Therefore,the corro-sion potential for the same extent of superplastic deformation would become more noble from postforming T6,RRA to T73tempered condition,as shown in Table V.The semicoherent ␩'and incoherent ␩precipitates are well known to be more anodic than the matrix of the aluminum alloy.[24,25]It is found that by increasing the degree of aging from the postforming T6to the postforming T73temper,the average size and volume fraction of the more anodic ␩'and ␩precipitates were increased,but the distributed num-ber and distributed uniformity of those precipitates were decreased.Generally,when the constituents are small,pres-ent in the greatest number,and uniformly distributed throughout the matrix,maximum corrosion resistance can be obtained.[25]Therefore,under the same ETS condition,the postforming T73heat treatment could reveal the highest corrosion current density.Table V also shows that the pit-ting potential would become more negative,and the pitting current density would increase from postforming T6,RRA to T73temper as in the same ETS condition.These results indicate that the precipitations of the ␩'and ␩can reduce the stability of passive ﬁlm and promote the pitting occur-rence.The different amounts of superplastic deformation were treated by the same postforming temper,which possessed the same microstructures.This means that the formation of cavitation is the major factor causing the decay of the mechanical properties and the SCC resistance when the ETS is increased for each postforming heat treatment.It is reasonable to understand that the cavitations will be-come the sites of stress concentration and crack initiation to cause the decay of mechanical properties.In addition,the corrosion reaction will also occur easily around the cavitations.Increasing the extent of superplastic defor-mation,resulting in the higher density of the cavitation,would increase the corrosion current density for the same postforming tempered condition.The cavitation can also break the continuity of the surface Al 2O 3ﬁlm and reduce the stability of the passive ﬁlm.It caused both the corro-sion potential and the pitting potential to shift to more anodic,and the passive current density to be increased with increasing the ETS under the same postforming tem-pered condition.The SCC susceptibility of the 7475Al alloy is mainly controlled by the hydrogen-induced cracking mechanism.[9]The RRA treatment can effectively improve the SCC resis-tance of T6temper for superplastic 7475Al alloy because RRA temper can produce larger sizes of both the matrix precipitates and GBPs than can T6tempered condition.[7]The larger diameter of GBPs in the RRA treatment can effectively trap the atomic hydrogen in bubbles nucleated at GBPs,and the larger size of the matrix precipitates will cause a decrease in the length and density of dislocation lines.These results can reduce the hydrogen concentration at grain boundary to below a critical value to inhibit hy-drogen embrittlement and improve SCC resistance.[11,12,16]Generally,the cathodic reaction of Al-alloy corrosion is the reduction of hydrogen ions.The atomic hydrogen produced from the corrosion reaction could become the main source of inducing the hydrogen embrittlement.The SCC suscep-tibility would be increased when the stress corrosion testing environment became more corrosive,as previously reported by some researchers.[26,27,28]Therefore,in the same micro-structure,a more serious corrosion reaction due to super-plastic forming means that more atomic hydrogen would be generated,then transported and stored up at the intersection of dislocation and grain boundary by mobile dislocations.[9]It indicates that increasing the extent of superplastic defor-mation will increase the SCC susceptibility under the same postforming tempered condition.In other words,the elon-gation loss,as indicated by a comparison of the elongation tested in air with that tested in solution,was increased with increasing the extent of ETS,as shown in Table IV.There-fore,the beneﬁt of improving the SCC resistance of the superplastically formed workpiece by means of postforming RRA or T73temper would be decreased with increasing the amount of superplastic deformation.The following conclusions about the inﬂuence of super-plastic deformation on the SCC can be deduced from the previous discussions:The superplastically formed work-piece should be treated by a suitable postforming heat treat-ment,such as RRA tempered treatment,to improve the mechanical strength and reduce SCC susceptibility.How-ever,the cavitations followed by the superplastic forming inﬂuence not only the mechanical properties but also the corrosion and SCC resistances.Increasing the extent of su-perplastic deformation,which creates more cavitations,can result in the severe decay of the corrosion properties and of the SCC resistance.The advantage of improving the SCC resistance while not sacriﬁcing the strength by means of the postforming RRA tempered condition will be de-creased with increasing the extent of superplastic defor-mation.Therefore,it is important to pay attention to the effect of cavities on the SCC susceptibility.Improving and using a suitable superplastic forming technique,such as hy-drostatic pressure,to reduce the formation of cavitation is necessary.Bampton et al.[3,20]showed that the cavitationFig.6—The typical corrosion morphologies of the superplastically formed specimens with various postforming heat treatments:(a)T6,(b)higher magniﬁcation of area A in(a),(c)RRA,(d)higher magniﬁcation of area B in(c),(e)T73,and(f)higher magniﬁcation of area C in(e).could be suppressed by using a back pressure.Reducing the formation of cavitation could retard the serious SCC damage when the superplastically formed workpiece is ap-plied in a corrosive environment.V.CONCLUSIONS1.Under the same post-tempered condition,the mechanicalproperties are decreased with increasing the extent ofFig.7—(a)through(c)TEM micrographs showing the PFZ width of the various postforming tempers:(a)T6,(b)RRA,(c)T73,(d)through(f)showing the grain boundary precipitates of the various postforming tempers(d)T6,(e)RRA,and(f)T73;and(g)through(i)showing the deformation structure after4pct plastic strain for the various postforming tempers(g)T6,(h)RRA,and(i)T73.[112]matrix zone axis and gϭ͗͘for all micrographs.111superplastic deformation.The inﬂuence of cavitation on the decay of elongation of the superplastically formed workpieces is greater than that on the decay of its strength.2.The SCC susceptibility is the most severe for postform-ing T6temper,intermediate for postforming RRA tem-per,and minimal for postforming T73temper under the same extent of superplastic deformation.The postform-ing RRA temper can effectively improve the SCC re-sistance of postforming T6temper and does not sacriﬁce mechanical strength.However,the SCC resis-tance is decreased with increasing the extent of super-plastic deformation for each postforming temper.The beneﬁt of improving the SCC resistance by means of the postforming RRA tempered condition will be de-creased if the extent of superplastic deformation is in-creased.3.Increasing the amount of superplastic deformation,re-sulting in higher density of cavitation,would cause both the corrosion potential and the pitting potential to be-come more anodic,and the increase of both the corro-sion current density and the passive current density for the same postforming tempered condition.A more vig-orous corrosion reaction of the materials due to super-plastic deformation is the main factor to increase the SCC susceptibility.4.The SSRT results indicated that it is necessary to payattention to the SCC susceptibility of the superplastically formed workpieces.These workpieces need not only a suitable post heat treatment,such as RRA tempered treatment,but also an appropriate superplastic forming technique to reduce the formation of cavitation and re-tard serious SCC susceptibility.ACKNOWLEDGMENTSThe authors are grateful for the support of the National Science Council of the Republic of China under Contract Nos.NSC82-0405-E002-099and NSC83-0416-E002-020.REFERENCES1.J.A.Wert,N.E.Paton,C.H.Hamilton,and M.W.Mahoney:Metall.Trans.A,1981,vol.12A,pp.1267-76.2.Superplasticity and Superplastic Forming,C.H.Hamilton and N.E.Paton,eds.,TMS,Warrendale,PA,1989.3.C.C.Bampton and R.Raj:Acta Metall.,1982,vol.30,pp.2043-53.4.M.W.Mahoney,C.H.Hamilton,and A.K.Ghosh:Metall.Trans.A,1983,vol.14A,pp.1593-98.5.C.C.Bampton and J.W.Edington:J.Eng.Mater.Technol.,1983,vol.105,pp.55-60.6.W.Gruhl:Z.Metallkd.,1984,vol.75,pp.819-26.7.T.C.Tsai and T.H.Chuang:Metall.Mater.Trans.A,1996,vol.27A,pp.2617-27.8.T.D.Burleigh:Corrosion,1991,vol.47,pp.89-98.9.D.Nguyen,A.W.Thompson,and I.M.Bernstein:Acta Metall.,1987,vol.35,pp.2417-25.10.J.Albrecht,I.M.Bernstein,and A.W.Thompson:Metall.Trans.A,1982,vol.13A,pp.811-20.11.J.K.Park and A.J.Ardell:Metall.Trans.A,1984,vol.15A,pp.1531-43.12.L.Christodoulou and H.M.Flower:Acta Metall.,1980,vol.28,pp.481-87.13.G.M.Scamans,R.Alani,and P.R.Swann:Corr.Sci.,1976,vol.16,pp.443-59.14.B.M.Cina:U.S.Patent3856584,Dec.24,1974.15.M.U.Islam and W.Wallace:Met.Technol.,1983,vol.10,pp.386-92.16.K.Rajan,W.Wallace,and J.C.Beddoes:J.Mater.Sci.,1982,vol.17,pp.2817-24.17.M.T.Cope,D.R.Evetts,and N.Ridley:Mater.Sci.Technol.,1987,vol.3pp.455-61.18.L.B.Duffy,J.B.Hawkyard,and N.Ridley:Mater.Sci.Technol.,1988,vol.4,pp.707-12.19.R.N.Parkins,F.Mazza,J.J.Royuela,and J.C.Scully:Br.Corros.J.,1972,vol.7,pp.154-67.20.C.C.Bampton,M.W.Mahoney,C.H.Hamilton,A.K.Ghosh,and R.Raj:Metall.Trans.A,1983,vol.14A,pp.1583-91.21.N.A.Pratten:J.Mater.Sci.,1981,vol.16,pp.1737-1747.22.S.Ohsaki and T.Takahashi:J.Jpn.Inst.Light Met.,1985,vol.35,pp.261-68.23.M.Yasuda,F.Weinberg,and D.Tromans:J.Electrochem.Soc.,1990,vol.137,pp.3708-15.24.S.Maitra and 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