2004届硕士研究生学位论文摘要

2004届硕士研究生学位论文摘要
材料加工工程
论文题目：高强度高韧性贫铀合金（U-Nb-Zr）热处理工艺研究
Study on the Heat-Treatment of Du Alloys
With High Strengh and High Toughness
研究生姓名：郭洪
导师姓名：李冠兴院士
协助导师：任慧平教授
杨继先任永岗研究员
专业：材料加工工程
摘要：
U-Nb-Zr合金作为动能穿甲弹的材料，要求具有高强度、高韧性的特点。

为了获得最佳的性能搭配，就要从成分、工艺、组织、性能等各方面入手，对合金进行深入系统的研究。

本论文以金相研究为重点，综合运用力学性能测试、X射线衍射、断口分析等手段，由纵向、横向两个方面比较分析热处理工艺和合金成分对组织和性能的影响，从而得出在“淬火+回火”热处理工艺条件下，U-Nb-Zr合金组织及性能的变化规律，并分析了Nb、Zr在合金中的作用。

在此基础上，提出获得高强度、高韧性贫铀合金的成分范围和相应的加工及热处理工艺。

关键词：U-Nb-Zr合金热处理高强度、高韧性
ABSTRACT
As a material for dynamic energy projectile, U-Nb-Zr alloys should possess the characteristics of high strength and high toughness. In order to obtain the optimal comprehensive properties, we studied the alloys in the aspects: components, craft, microstructure, and mechanical properties. In the course of research, the work of metallurgical analysis was in the first place. Meanwhile, the mechanical properties were tested, the structure of crystalline analyzed, the morphology of fracture observed. By all these means, the effects of heat-treatment and components on properties and structure have been made out. Thus, the rules of properties and structure's evolution in the heat-treatment (quenching + tempering), are clear, and the roles of Nb and Zr in the alloys are drawn out. On the basis of these works, the range of components, and the craft of heat-treatment and working are provided.
Key words：U-Nb-Zr alloy heat-treatment high strength high toughness
论文题目：薄板坯CSP连轧热力耦合有限元模拟
Thin Slab CSP Thermal Mechanical Coupled
Fem Simulation during Continuous Rolling
研究生姓名：李传瑞
导师姓名：王宝峰教授
专业：材料加工工程
摘要:
薄板坯连铸连轧是20世纪80年代成功开发的一种全新的生产热轧板卷的工艺，是钢铁工业最重大的革命性技术之一。

与传统热轧板带钢相比，薄板坯连铸连轧具有非常大的优越性。

因此世界各国都给予极大关注，在冶金界产生极大反响。

典型的薄板坯连铸连轧技术包括CSP技术、ISP技术和FTSR技术。

其中CSP技术应用最多。

据统计，1997年世界有CSP生产线20条，占薄板坯连铸连轧线的70％，CSP生产的热轧板占世界钢产总量的5％。

预计到2013年，CSP生产的热轧板占世界钢产总量的50％。

可见CSP 技术有很大的发展前景。

1997年，我国的广东珠江钢铁公司、河北的邯郸钢铁公司以及内蒙古的包头钢铁公司分别从德国的SMS引进3条CSP生产线，并相继建成投产，年生产能力在200万t/a 。

最近，我国的唐山钢铁公司、通化钢铁公司、马鞍山钢铁公司以及涟源钢铁公司等企业也计划建立薄板坯连铸连轧生产线。

薄板坯连铸连轧技术具有广阔的发展前景，因此研究与此相关的课题具有一定的必要性。

目前，由于计算方法与数值模拟理论的结合，极大的推动了轧制技术的发展。

同时，也使得对钢材生产过程中变形、温度的计算机模拟成为可能。

本文是针对包头钢铁公司的CSP连轧生产工艺，借助Marc商用软件，采用热力耦合分析技术，建立大变形弹塑性有限元数学模型，分析薄板坯的连续轧制变形过程。

包括以下内容。

1 综合考虑了板坯与轧辊的接触换热、板坯与周围环境的对流辐射换热、机架间冷却水的冷却作用、塑性变形和摩擦而产生的热量等条件对温度变化的影响，计算了板坯内部的温度场，分析了板坯内的温度变化情况，得出其温度变化规律。

2 计算变形区内等效应力场、等效应变场、等效应变速率场，分析了板坯内三者各自的变化情况。

3 计算轧制过程中的轧制力，分析了轧制力的变化情况。

本文结合薄板的生产过程，对变形过程中的温度场以及力能参数进行研究，所得到的分布规律，可以为工业生产提供参考。

关键词：CSP Marc 热力耦合有限元模拟
ABSTRACT
Thin slab continuous casting rolling is a new technique of hot rolling strip curl product. It is one of the most important revolutionary technologies. Compared with traditional hot slab product, this technology has many advantages. So a large number of countries show great concern about it.
Typical thin slab continuous casting rolling technology includes CSP, ISP and FTSR. Yet CSP technology is used widely nowadays. It is reported that there are more than twenty CSP production lines all over the world, accounting for 70 percent of thin slab continuous casting rolling lines. Hot rolling strip produced by CSP accounts for 5 percent of total steel output. It is calculated that hot rolling strip produced by CSP will amount to 50 percent of total steel output by 2013.
In 1997, three CSP lines were introduced from SMS and were put up individually in Zhu Jiang iron and steel company, Han Dan iron and steel company and Bao Tou iron and steel company. They have put into use now. Their design capacity amounts to 200 million tons annually.
Now that thin slab continuous casting rolling is boomed rapidly, it is necessary to research subject about that.
The rolling technique get much from the mutual development of computation methods and mathematical imitation which make it possible to simulate the deformation and temperature evolution in the process.
In this article,the six passes hot rolling process of thin slab was studied with the aid of two dimensional elastic-plastic and thermal-mechanical coupled FEM using commercial software Marc. What were researched is as fellows:
The distribution and change of temperature field in rolling process were analyzed. In view of boundary conditional influence on temperature, some factors such as thermal exchange between rolling and rolled piece, plastic deforming quantity of heat, cooling flux, convection and radiation heat exchange were considered during simulation. The parameters of rolling mechanical property during deformation such as equivalent stress, equivalent strain and equivalent strain rate were investigated. The results showed that elastic-plastic and thermal-mechanical coupled FEM could correctly reflect metal deformation.
Under the background of the development of thin slab rolling in our country, the presented temperature and mechanical property parameters distribution and rules may come up with reference to industrial production.
Key words: CSP Marc heat-mechanical coupled FEM simulation
论文题目：快淬AB
型贮氢合金电化学性能及其微观结构的研究
5
The Investigations on Electrochemical Performances and
Microstructures of Rapid Quenching AB
-type Hydrogen Storage
5
Alloys
研究生姓名：王国清
导师姓名：张羊换教授
专业：材料加工工程
摘要:
AB5型稀土系贮氢合金，作为Ni/MH电池负极材料已得到大量研究和广泛应用。

为了提高Ni/MH电池的市场竞争力，降低贮氢合金的生产成本和提高合金的电化学性能成为贮氢合金研究的主要方向。

目前研究的焦点是如何提高低钴、无钴贮氢合金的电化学循环稳定性。

本文旨在通过合金成分的优化调整，同时结合适当的快淬工艺，改善低钴无钴贮氢合金的循环稳定性，制备出综合性能优异的贮氢合金电极材料。

本文主要应用熔炼法和真空快淬技术制备AB5型贮氢合金，用开口式三电极系统测试合金的电化学性能，用XRD分析了铸态及快淬态合金的相组成及相结构，用SEM和光学显微镜观察了铸态及快淬态合金的微观组织形貌，用TEM观察了铸态及快淬态合金的形貌并用SAD确定其晶态。

全面研究了合金微观结构与其电化学性能的联系，得到如下一些主要结论：
1. 综合研究了Mm(NiMnSiAl)4.3Co0.6-x Fe x（x=0, 0.2, 0.4, 0.6）系列铸态和快淬态合金的微观结构及电化学性能。

结果表明，Fe替代Co导致合金的电化学容量下降，但不同程度的改善了合金的循环稳定性。

Fe替代Co对快淬态合金循环寿命的提高比较显著，这主要是由于随Fe替代量的增加，快淬态合金的晶粒明显细化。

快淬工艺可以极大地提高合金的循环寿命。

2. 对铸态及快淬态低钴无钴La x Mm1-x(NiMnSiAlFe)4.7Co0.2 (x=0, 1)和La x Mm1-x(NiMnSiAlFe)4.9(x=0, 1)两个系列铸态和快淬态合金的研究结果表明，La替代Mm使合金放电容量提高，其主要原因是合金中第二相的消失和晶胞体积的增大。

3. 研究表明，通过以Fe替代Co、成分优化设计以及应用真空快淬工艺研制低钴无钴AB5型贮氢合金是可行的。

实验发现两种成分的低钴无钴合金可以达到实用化需求。

这两种合金成分是La(NiMnSiAlFe)
4.7Co0.2和La(NiMnSiAlFe)4.9，活化次数为2次，最大放电容量分别为309.42mAh/g 和304.47mAh/g，循环寿命分别为370和300次。

关键词：AB5型贮氢合金，低钴无钴，快淬，循环稳定性
ABSTRACT
AB5-type rare-earth-based hydrogen storage alloy, as the negative electrode material of the Ni/MH batteries, has been extensively investigated and widely applied. In order to exalt the competition ability
of Ni-MH batteries in the rechargeable battery market, the investigation on the AB5-type hydrogen storage alloy has been carrying out to enhance the electrochemical performances and reduce the production cost of the alloy. At present, the investigation focus on the AB5-type hydrogen storage alloy is how to increase the cycle stability of Low-Co and Co-free electrode alloy. This thesis intends to get a kind of hydrogen storage alloy with great synthetical properties through optimizing the composition and right rapid quenching technology.
AB5-type hydrogen storage alloys were prepared by casting and rapid quenching. The electrochemical performances of the experimental alloys were measured by an open tri-electrode system. The microstructures of the as-cast and quenched alloys were studied systematically: the phase structures were analyzed by XRD, the microstructures and morphologies were observed by SEM and Optics microscope, the crystalline state and morphologies were determined by SAD and TEM. The influences of rapid quenching technology on the microstructures and electrochemical performances of the experimental alloys were researched in detail, and some important conclusions were obtained.
1. The microstructures and electrochemical performances of the as-cast and quenched Mm(NiMnSiAl)4.3Co0.6-x Fe x (x=0, 0.2, 0.4, 0.6) alloys were synthetically investigated. The results show that substitution Fe for Co leads to decrease of the discharge capacity and improve of the cycle life of the alloys to some degree. Especially, the effect of substitution Fe for Co on the cycle life of the as-quenched alloys is outstanding. This is mainly attributed to the grain refinement produced by the increase of the amount of Fe content. Rapid quenching can greatly improve the cycle life of the alloy.
2. The electrochemical performances and microstructures of the as-cast and quenched Low-Co and Co-free La x Mm1-x(NiMnSiAlFe)4.7Co0.2(x=0, 1) and La x Mm1-x(NiMnSiAlFe)4.9(x=0, 1) electrode alloys were researched and results show that, the substitution La for Mm makes the increase of the discharge capacity of Low-Co and Co-free alloys. The main reason is that the secondary phase disappears and the lattice volume augments when La substitutes Mm in the Low-Co and Co-free alloys.
3. The investigations show that it is feasible to prepare and develop the Low-Co and Co-free AB5-type hydrogen storage alloys by substitution Fe for Co, component optimizing design and using rapid quenching technology. Two kinds of the Low-Co and Co-free alloys which can attain the requirement of the practical application are discovered. The alloys are La(NiMnSiAlFe)
4.7Co0.2 and La(NiMnSiAlFe)4.9with the activation property of 2 cycles, the maximum discharge capacity of 309.42mAh/g and 304.47mAh/g, and the cycle life of 370 and 300 cycles respectively.
Key words: AB5-type hydrogen storage alloy; Low-Co and Co-free; rapid quenching; cycle stability
论文题目：热处理工艺及稀土元素对Ni-Mn-Ga磁性形状记忆合金性能的影响Influence of Heat Treatment Process and Rare Earths on
the Properties of Ni-Mn-Ga Magnetic Shape Memory Alloys
研究生姓名：李雪梅
导师姓名：赵增祺教授
专业：材料加工工程
摘要:
本文主要研究了不同热处理制度和稀土元素对Ni-Mn-Ga合金马氏体相变温度和磁感生应变的影响。

利用交流磁化率测定仪测定合金的相变温度和居里温度，利用动态电阻应变仪和特斯拉计测定合金的磁感生应变，并利用XRD、SEM等实验技术研究了合金的相结构和微观结构。

对合金进行不同制度的热处理，研究其对合金性能的影响，并以此为据选用最佳的热处理工艺。

研究结果表明：热处理制度不同，对合金引入的内应力不同，内应力越大，合金的相变温度越低，同时磁感生应变也越小。

对合金Ni52.5Mn23.5Ga24-XTbX(X=0,0.1,0.2,0.4)和合金Ni52Mn24.7Ga23.3-XDyX(X=0,0.1, 0.2,0.4)研究不同含量的稀土元素对合金性能的影响。

稀土元素对合金晶体结构没有影响；添加稀土元素显著提高了合金的相变温度，使合金的相变热滞后稍有降低，同时对合金的居里温度影响不大；添加稀土元素合金的晶粒明显细化，改善了合金的机械性能。

无外加应力作用下，添加稀土元素合金的磁感生应变值较低，但当外加应力与磁场作用方向相同时，添加稀土元素合金的磁感生应变值很高，最大可达0.3%以上。

定向凝固试样的磁感生应变值比相应铸态试样的高，最大为0.85%。

关键词：Ni-Mn-Ga合金; 热处理制度; 稀土; 相变温度; 磁感生应变
ABSTRACT
The effect of different heat treatment process and rare earth on martensitic transition and magnetic-field-induced strain in Ni-Mn-Ga alloys are investigated. Martensitic transformation temperature and the Curie temperature were determined by means of ac magnetic susceptibility. A metal foil strain gauge was attached on samples for measuring strains as a function of the magnetic field at room temperature.Crystal structure was identified by X-ray diffractometer using Cu Kαradiation at room temperature. Fracture surfaces of the compression test specimens and micrographs of sample were observed with scanning electron microscope(SEM).
Effect of various contents rare earth on transformation properties and magnetic properties as well as mechanical properties of alloys were studied. The results showed that rare earth had little influence on the crystalline structure and the Curie temperature and remarkable increased the transformation
temperature and decreased temperature hysteresis . SEM studies revealed that the mechanical strength was enhanced by reduced sizes of grains. It was found that magnetic-field-induced strain was reduced by adding rare earth without pressure but was increased up to 0.3% when pressure was exerted. The strain of directions of polycrystal was larger than that of cast specimens.
Key words ：Ni-Mn-Ga alloy; heat treatment process; rare earths; transformation
temperature; magnetic-field-induced strain
论文题目：室温磁致冷材料锰锗，锰锗硅，锰锗锑系列合金磁热效应的研究
The Study of Magnetocaloric Effect of Mn 5Ge 3，
Mn 5Ge 3-x R x (R=Si,Sb) Alloys At Near-Room Temperature
研究生姓名：洪 波
导师姓名：徐来自 研究员
专 业：材料加工工程
摘 要:
由于氟里昂对生态环境产生严重的危害，所以开发一种全新的室温制冷技术来取代传统的制冷技术，已经受到世界各国的重视。

借助磁性材料的磁热效应，而研制的磁致冷技术以其高效，节能，无环境污染等特点，成为目前关注的热点。

本文主要研究锰锗系列合金在低磁场下（1.3T ）的磁热效应。

在此篇论文中，对锰锗，锰锗硅，锰锗锑合金的铸态及粉末样品进行了对比与研究。

首先，通过高频真空悬浮炉和行星式高能球磨机制备Mn 5Ge 3，Mn 5Ge 3-x Si x (x=0.2，0.5，1.5)系列合金以及Mn 5Ge 3-x Sb x (x=0.1，0.2，0.5)系列合金的铸态及粉末样品；然后利用自制的ad T －T 曲线测量仪直接测量三组不同系列合金铸态及粉末样品在低磁场下的磁热效应；借助X －射线衍射分析技术，分析研究成分和高能球磨对合金磁热效应的影响及可能存在的原因。

对锰锗，锰锗硅，锰锗锑三种合金材料的研究发现，硅元素的加入使材料的居里温度下降，且材料的磁热效应也随硅元素含量的增加而下降；锑元素的加入使材料的居里温度升高，而材料的磁热效应随锑元素含量的增加而下降。

对于大量固态磁致冷材料的研究表明，目前还没有任何一种金属或合金在低磁场下，室温附近的磁热效应超过金属钆。

因此，我们提出开发具有磁热效应的磁液体的方案。

根据理论推倒，当磁致冷材料颗粒达到一定粒度时，出现超顺磁性，并且可能放大材料的磁热效应。

对经机械球磨后锰锗系列合金的研究表明，由于材料在球磨过程中受长时间，周期性机械力作用，而产生晶
格扭曲，导致材料磁热效应的下降。

为使合金粉末的磁热性能达到试验用样机磁液体的要求，我们用热处理的方法恢复合金粉末的晶格扭曲，使合金粉末的磁热效应回升。

实验表明制定合适的热处理工艺可以使扭曲的晶格得到恢复，同时合金粉末的磁热效应也得到回升。

关键词：锰锗锑合金 锰锗硅合金 磁热效应 热处理
ABSTRACT
Because of the ecological harmfulness of freons ,the question of development and production of substitutive refrigeration devices operating in the room temperature range has become topical. Magnetic refrigeration technique, whose principle of operation uses to the magnetocaloric effect, is becoming focus of research in the world for its high efficiency, less energy and ecological harmfulness.
The magnetocaloric effect of the room temperature magnetic refrigeration materials, such as Mn 5Ge 3, Mn 5Ge 3-x Sb x and Mn 5Ge 3-x Si x alloys, at low magnetic field of 1.3 Tesla were studied in the present paper. First,the casting and powder of Mn 5Ge 3, Mn 5Ge 3-x Sb x and Mn 5Ge 3-x Si x alloys were prepared using high frequency vacuum levitation furnace and a planetary ball mill., Second the magnetocaloric effects of the alloys were measured directly by using the self-made ad T －T curve measurement devices at the field of 1.3 Tesla. Last, the possible causes of the composition change and ball milling affect the magnetocaloric effects of the alloys were analyzed by XRD method.
As research shows, the magnetocaloric effect and Curice temperature of Mn 5Ge 3-x Sb x and Mn 5Ge 3-x Si x alloys varies with the consistery of Si 、Sb respectively.Study of powdered alloys shows that magnetic materials results in distorted crystal lattice with long time and recurrent effect of mechanical force. Because of the reasons, the magnetocaloric effects of materials decreases with the decreases of sized powder. The distortion of crystal lattice has been recovered by using heat treatment. The magnetocaloric effect of alloy powder is improved by the proper heat treatment.
Key words: Mn 5Ge 3-x Sb x Mn 5Ge 3-x Si x magnetocaloric effect heat treatment
论文题目：310乙字钢轧制过程实验研究及三维有限元模拟
Experimental Research and 3D FEM Simulation on 310 Z shape Steel
研究生姓名：苏光
导师姓名：陈林教授
协助导师：王秉义教授级高工
专业：材料加工工程
摘要:
310乙字钢是铁路货车车厢的重要结构件。

从技术角度讲，310乙字钢变形复杂、生产技术难度大、孔型设计要求高。

包钢轨梁厂生产的310乙字钢一直采用现有的孔型系统，在轧制过程中存在腿部在孔型中充不满，造成腿部尺寸短尺的技术难题。

为了分析研究310乙字钢在孔型中的变形规律及孔型设计对产品质量的影响，本文采用了轧制实验和有限元模拟两种方法进行研究。

本文针对孔型系统，将孔型缩小为实际尺寸的1/5，利用实验轧机轧制铅试样的实验方法，研究了孔型形状参数、道次压下量等因素对310乙字钢成型的影响，为改变孔型系统、提高产品质量提供了解决的方向。

实验结果表明：增长短腿水平投影长度有助于短腿的伸长。

同时，实验室轧制的过程也为有限元模拟提供了计算策略。

在轧制实验的同时，采用显式有限元软件ANSYS/LS-DYNA，对310乙字钢的轧制过程进行弹塑性有限元模拟，研究了950Ⅱ孔轧制变形过程中各道次轧件断面节点的x、y方向的流动规律。

同时在模拟过程中，采用了多种方案进行模拟，对各种计算结果进行相互的比较，其变形规律与实验室模拟结果是一致的，从而可以得出应用有限元软件进行轧制过程的实验模拟是可靠的。

运用数值模拟方法，采用不同的孔型系统方案，模拟分析了采用连铸坯料轧制310乙字钢的可行性。

通过比较结果，选用最优的方案（即D轧制方案）进行工业试验，从而减少了实验室试验的环节，缩短了产品开发的步骤，降低了产品研制的成本，提高了产品的市场竞争力。

为了使ANSYS有限元软件能够具有在分析310乙字钢轧制过程中的通用性，本文在ANSYS软件的基础上，采用APDL和UIDL相结合进行了二次开发，编写了适用于现场工程技术人员使用的310乙字钢模拟分析程序。

关键词：型钢轧制实验有限元模拟 ANSYS 二次开发
ABSTRACT
310 Z shape steel is the important section of the carriage in the lorry. In the view of technique, 310 Z shape steel rolling has the complex deformation, the rolling technique is very difficulty and the roll pass design has the high request. For the 310 Z shape steel rolling, the plant of rail and beam of Bao Gang has used the current roll pass. During the rolling, the section of the leg has not permeated the roll
pass. So the shape of leg was not very perfection.
In order to study the rule of the deformation in the roll pass and the effect of the roll design to the quality of the product, two kinds of methods i.e. experimental rolling and FEM simulation are used in profound research works.
The rolling experiments were performed in the rolling mill of laboratory with lead, the roll pass scale is 1:5 according to the actual size of 310 Z shape steel. The effect of rolling design and the reduction to the molding of the 310 Z shape is the topic of the research works. We can conclude that the shorter leg will increase when the length of the projection of the shorter leg. The results will offer the aspect for increasing the quality of the product and calculation strategy for FEM simulation.
Meanwhile, the dynamic explicit elastic-plastic element method simulation of the 310 Z shape steel rolling process under the same rolling condition was performed with the FEM software ANSYS/LS-DYNA. The flowing rule of the metal with the x and y direction can be received after studying the deformation of the Z shape steel in the 950 Ⅱ. Some scheme of simulation will be adopted in the research. Having analyzed the results, the deformed rule in the simulation accords with the result of the lab experimental. And it will prove that the method of FEM in the rolling is reasonable.
The FEM method will be exerted to analyze the feasibility of rolling the 310 Z shape steel on base of the continuously casting billet. After investigating the results, the optimization scheme (the D scheme) can be adopted to carry through the industrial experimentation. This method can cut down the lab experimentation, so it will depress the cost of exploiting the new product and enhance the competitive capability of the manufacture in the market.
In order to use the ANSYS FEM software to simulate the 310 Z shape steel roll, on the basis of ANSYS, the research adopts the APDL and UIDL to make a program for the engineers who work in the location of the production.
Key words:section steel, rolling experiment, FEM, simulation, ANSYS, re-development
论文题目：热变形Nd-Fe-B稀土永磁材料组织和织构的研究
Study on Microstructure and Magnetic Texture of Hot-deformed
NdFeB Rare Earth Permanent Magnets
研究生姓名：计云萍
导师姓名：任慧平教授
专业：材料加工工程
摘要:
本文研究了热变形Nd-Fe-B稀土永磁材料的铸锭组织和热变形过程中组织与织构的变化。

合金在真空中频感应炉冶炼，随后进行不同工艺的热变形及热处理。

然后观察显微组织，采用X射线衍射的方法分析织构的变化。

结果表明：Nd-Fe-B合金铸锭中Nd2Fe14B相生长成片状晶，若干个彼此近似平行排列的片状晶组成一个片状晶团。

热压变形可细化主相晶粒，且随着形变量的增大，主相Nd2Fe14B晶粒进一步细化，同时富Nd相沿晶界均匀分布。

富Nd相在热压时可呈液相，液态的富Nd晶界相在热变形过程中起润滑作用，有利于主相晶粒的转动和位移。

热处理之后边界显微结构得到改善。

在700℃，形变速率为10－4～10－3/s的热压变形工艺下，得到以(006)晶面的衍射峰为主峰的织构，即(006)织构，随形变量的增大，(006)织构进一步增强。

初始织构对热变形Nd-Fe-B永磁合金的磁织构有很重要的影响，当试样的初始织构不显著时，热轧变形后Nd-Fe-B永磁合金的磁织构增强，当试样有非常发达的初始织构时，热轧变形后的Nd-Fe-B永磁合金的磁织构减弱。

关键词：Nd-Fe-B；稀土永磁；热变形；织构
ABSTRACT
The microstructure of Nd-Fe-B ingot and the influence of hot-deformation on microstructure and magnetic texture of Nd-Fe-B permanent magnetic alloys were studied. The alloys were smelted in vacuum intermediate-frequency induction furnace, then the samples were hot deformed and carried through heat treatment. Microstructure was observed and texture was analyzed by X-ray diffraction. Results show that the growth of Nd2Fe14B grains during solidification is in sheet-like pattern and several nearly parallel lathes form a group of sheet. Hot-pressing deformation refines the grains and with the increment of deformation ratio, the Nd2Fe14B grains are further refined and Nd-rich phase is in well-proportioned distribution along the crystal boundary. Nd-rich phase during hot-pressing deformation is in liquid state and it plays a lubricant role in hot-pressing deformation in order to make Nd2Fe14B grains rotate and move beneficially. Heat treatment improves the crystal boundary microstructure. (006) texture is obtained by hot-pressing deformation at 700℃with a deformation rate of 10－4～10－3/s and, with the increment of deformation ratio, (006) texture is further strengthened. In addition, the initial texture of Nd-Fe-B ingot is very important to form magnetic texture during hot-deformation. Hot-rolling deformation may increase the magnetic texture of Nd-Fe-B magnets when the initial texture is not very pronounced. Conversely, an ingot with a well-developed initial texture may have its magnetic texture decreased by rolling.
Key words: Nd-Fe-B; rare earth permanent magnets; hot deformation; texture
论文题目：热变形钕铁硼永磁材料加工处理工艺对组织和磁性能的影响
Effect of Cure Technique on Microstructure and
Magnetic Properties of Hot-Deformation NdFeB Magnets
研究生姓名：王晓军
导师姓名：李文学教授
专业：材料加工工程
摘要:
本文主要研究NdFeB永磁材料热压变形的可行性及加工处理工艺对NdFeB永磁材料显微组织和磁性能的影响。

分析了化学成分、铸锭组织、热变形量、热形变温度和热处理对NdFeB永磁材料显微组织和磁性能的影响。

结果表明：NdFeB永磁材料铸锭组织为柱状晶。

在热压时，随着热变形量的增加，NdFeB永磁材料的晶粒变得细小，显微组织得到改善，磁性能提高。

获得NdFeB永磁材料最佳磁性能的热形变温度与Nd含量有关，随Nd含量的提高，热形变温度降低。

通过热处理，使Nd２Fe14B晶粒长大，主相Nd２Fe14B体积百分数增加，NdFeB永磁材料的磁性能得到提高。

关键词：NdFeB永磁材料、铸锭组织、热变形、热处理、显微组织、磁性能
ABSTRACT
This paper studied the possibility of NdFeB magnets hot-deformation treatment and the effect of cure technique on microstructure and magnetic properties of NdFeB magnets. Chemistry component ,ingot structure, hot-deformation and heat treatment effect microstructure and magnetic properties of NdFeB magnets . Experiments showed that for the hot-deformed NdFeB magnets grain size decreases，microstructure and magnetic properties improves as hot-deformation increases．Hot-deformed temperature of obtained best magnetic properties relates content of Nd；Hot-deformed temperature decreases as content of Nd increases. Across heat treatment , Nd２Fe14B crystal grain grows up ；magnetic properties of NdFeB magnets increases as Nd２Fe14B volume percent enchances．
Key words: NdFeB magnets, ingot structure, hot-deformation, heat treatment, microstructure, magnetic properties
论文题目：La1-x Ca x MnO
纳米结构的制备及磁热效应的研究
3
Preparation and Magnetocaloric Effect of La1-x Ca x MnO
3
Nanostructure
研究生姓名：赵辉荣
导师姓名：李保卫教授
协助导师：任永岗研究员
王正德副教授
专业：材料加工工程
摘要：
室温磁致冷技术是一种新型致冷技术，因其潜在的优势而倍受科研工作者的关注。

由于室温磁致冷技术具有无污染、低噪音、能耗小、体积小、易维护、寿命长等优点，国际上对室温磁致冷技术研发的投入非常大，我国对该技术已进行一定的研究。

磁致冷技术的关键是磁致冷工质，其性能如何将直接影响制冷机的制冷性能和效益。

近10年来由于La1-x Ca x MnO3（LCMO）化合物具有居里温度可调，化学性能稳定，价格便宜，电阻率较高等优点，适合作为室温磁致冷材料而引起国内外广大研究工作者的广泛关注。

本文针对La1-x Ca x MnO3（LCMO）系致冷工质进行了研究。

本论文的研究工作主要包括室温纳米磁致冷材料La1-x Ca x MnO3（x=0.2、0.3、0.4、0.5）系化合物的制备、影响形状和大小的因素及其在低磁场（1.4T）下的磁热效应。

本论文采用水热共沉淀退火法制备了La1-x Ca x MnO3（x=0.2、0.3、0.4、0.5）系纳米结构，用X射线衍射仪确定产物为单相钙钛矿结构，无任何杂峰及第二相；用扫描电子显微镜与透射电子显微镜分析了产物的大小和形貌，发现水热温度对产物的形成起决定作用，随着温度的升高，产物由薄膜状向丝状转变，而溶液的碱度可控制产物的形貌和大小，当碱度为6.35mol/L，水热温度为240˚C时，La0.6Ca0.4MnO3的主要形貌为纳米丝并有少量纳米颗粒，纳米丝平均直径为40nm；最后测量了粉末样品在低磁场（1.4T）下的磁热效应，发现水热共沉淀退火法制备样品的最大绝热温度明显高于球磨法制备样品的最大绝热温变。

在低磁场（1.4T）下测量的La1-x Ca x MnO3系纳米结构发现：绝热温度（ΔT ad）的温度跨度有变宽的趋势，且不用水热共沉淀退火法制备的La1-x Ca x MnO3系纳米结构的大小可为几十纳米，如果把形貌控制为大小一致的颗粒状，则可用它制备磁液体，使磁致冷样机热交换过程实现管道化，简化磁致冷样机的结构。

关键词：水热共沉淀退火法钙钛矿纳米结构磁热效应
ABSTRACT
Recently cooling technology has been used in every fields such as industry、agriculture etc.。