Effects of semi-solid isothermal process parameters on microstructure of Mg-Gd alloy
单晶硅表面等离子体基离子注入碳纳米薄膜的摩擦学特性
单晶硅表面等离子体基离子注入碳纳米薄膜的摩擦学特性IntroductionSingle-crystal silicon is a widely used material in various technological applications due to its desirable mechanical properties. However, its poor tribological behavior under sliding friction hinders its widespread use. Surface modification techniques such as ion implantation have been applied to enhance its tribological behavior. In this study, we investigated the frictional characteristics of carbon nanofilm implanted on a single-crystal silicon surface by plasma-based ion implantation.Experimental MethodsThe experiments were conducted using a plasma-based ion implantation system. The single-crystal silicon samples were cleaned and then implanted with carbon ions with varying energies and doses. The surface morphology and chemical composition of the implanted samples were characterized using scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The tribological properties of the implanted samples were evaluated by performing friction and wear tests using a ball-on-disk tribometer under dry sliding conditions.Results and DiscussionThe SEM images showed that the implanted samples exhibited a rougher surface compared to the unimplanted ones. The XPS analysis confirmed the presence of carbon on the implanted samples. The friction and wear tests revealed that the implantedsamples exhibited reduced friction coefficients and wear rates compared to the unimplanted samples. The reduced friction was attributed to the formation of a carbon-rich layer on the surface of the implanted samples, which acted as a solid lubricant during sliding. The reduced wear rate was attributed to the increased surface hardness of the implanted samples due to carbon ion implantation.ConclusionThe plasma-based ion implantation technique was successfully used to implant carbon ions on the single-crystal silicon surface. The implanted samples exhibited enhanced tribological behavior, including reduced friction coefficients and wear rates, compared to the unimplanted ones. The improved tribological behavior was attributed to the formation of a carbon-rich layer on the surface and the increased surface hardness due to ion implantation. We conclude that plasma-based ion implantation is an effective surface modification technique for improving the tribological behavior of single-crystal silicon.Furthermore, the specific implantation parameters used in this study, i.e., energy and dose, can be optimized to achieve even better tribological properties. For example, increasing the energy of the implanted ions can result in a deeper implantation and hence a thicker carbon-rich layer on the surface. Similarly, increasing the dose can result in a higher concentration of carbon atoms on the surface, which can lead to further reduction in friction and wear.The use of ion implantation for surface modification has several advantages over other traditional techniques such as coating orsurface texturing. Unlike coatings, ion implantation does not introduce a separate layer on the surface, which can delaminate or wear off over time. In contrast, implanted atoms become part of the substrate material, resulting in a more durable modification. Additionally, the surface texturing technique relies on creating grooves or patterns on the surface, which may not be applicable or effective for all materials or applications.In conclusion, the plasma-based ion implantation technique has been shown to be a promising surface modification technique for enhancing the tribological behavior of single-crystal silicon. This technique has the potential to be applied to other materials and can be optimized for specific applications. Future work can focus on optimizing the implantation parameters, investigating the long-term durability of the implanted surfaces, and exploring the applications of this technique in different technological fields.In addition to silicon, plasma-based ion implantation has been applied to a wide range of materials such as metals, polymers, ceramics, and semiconductors to modify their surface properties for various applications. For example, ion implantation has been used to improve the wear resistance and corrosion resistance of stainless steel, increase the hardness and scratch resistance of polymeric materials, and enhance the adhesion and surface energy of ceramics.Moreover, ion implantation can also be used to tailor the surface properties of materials for specific applications in microelectronics, optoelectronics, and biomedicine. In microelectronics, ion implantation is commonly used to modify the electrical properties of semiconductors such as silicon and gallium arsenide for devicefabrication. In optoelectronics, ion implantation can be used to create waveguides or modify the refractive index of optical materials for photonic devices. In biomedicine, ion implantation can be employed to modify the surface chemistry and topography of implant materials to enhance their biocompatibility and reduce the risk of rejection.In conclusion, plasma-based ion implantation provides a versatile and effective surface modification technique for various materials and applications. Its benefits include improving wear resistance, corrosion resistance, hardness, scratch resistance, adhesion, surface energy, and biocompatibility, among others. The technique can be optimized for specific applications and has potential in a wide range of technological fields. Future research should focus on further understanding the fundamental mechanisms of ion implantation and developing new implantation techniques to address emerging needs in different industries.One area where plasma-based ion implantation has shown potential is in the development of new types of functional coatings. Functional coatings are thin layers of material applied to surfaces in order to impart specific properties such as increased durability, improved friction, or enhanced thermal insulation. Plasma-based ion implantation can be used to create such coatings through a process known as ion beam assisted deposition.Ion beam assisted deposition involves bombarding a surface with high-energy ions while simultaneously depositing a thin film of material onto it. This bombardment modifies the surface properties of the material, allowing the deposited film to adhere more strongly and exhibit improved functional properties.One example of a functional coating that can be created through ion beam assisted deposition is a superhydrophobic coating. Superhydrophobic coatings are highly water-repellent, and can be used in applications such as self-cleaning surfaces, anti-fogging coatings, and water-resistant textiles. By using plasma-based ion implantation to modify the surface properties of a material, it is possible to create a highly rough surface with a variety of different structures that can prevent water from adhering to it.Another area where plasma-based ion implantation has shown promise is in the development of advanced energy materials. By modifying the surface properties of materials such as silicon, lithium, and aluminum, it is possible to create materials with improved energy storage properties. For example, by using ion implantation to create a highly porous silicon surface, researchers have been able to create silicon anodes for lithium-ion batteries with significantly improved performance.In conclusion, plasma-based ion implantation is a versatile technique with promising applications in a variety of fields. By modifying the surface properties of materials, it is possible to create coatings with improved functional properties and advanced energy materials with improved performance. Continued research in this area has the potential to lead to the development of new materials and technologies with a wide range of practical applications.In addition to functional coatings and energy materials, plasma-based ion implantation has also shown potential for use in the biomedical field. By modifying the surface properties of medical implants, it may be possible to improve biocompatibilityand reduce the risk of rejection or infection. For example, an ion-implanted titanium surface could have improved osseointegration and reduce implant failure rates.Furthermore, plasma-based ion implantation can also be used in the field of microelectronics to improve device performance. By modifying the surface properties of electronic components, it is possible to improve their conductivity and reduce power consumption. This can lead to smaller, more efficient devices that have better battery life and can be used in a wider range of applications.Finally, plasma-based ion implantation has potential in the field of environmental science. By modifying the surface properties of materials such as membranes and filters, it is possible to create materials with improved filtration properties. This can lead to more efficient water and air filtration systems that have a smaller environmental footprint.Overall, plasma-based ion implantation is a promising technology that has the potential to unlock new innovations in a wide range of fields. Continued research and development will be needed to fully understand its capabilities and limitations, but the potential benefits make it an exciting area to watch in the coming years.。
参考文献标准格式
参考文献规范格式一、参考文献的类型参考文献（即引文出处）的类型以单字母方式标识，具体如下：M——专著C——论文集N——报纸文章J——期刊文章D——学位论文R——报告对于不属于上述的文献类型，采用字母―Z‖标识。
对于英文参考文献，还应注意以下两点：①作者姓名采用―姓在前名在后‖原则，具体格式是：姓，名字的首字母. 如：Malcolm Richard Cowley 应为：Cowley, M.R.，如果有两位作者，第一位作者方式不变，&之后第二位作者名字的首字母放在前面，姓放在后面，如：Frank Norris 与Irving Gordon应为：Norris,F. & I.Gordon.；②书名、报刊名使用斜体字，如：Mastering English Literature，English Weekly。
二、参考文献的格式及举例1.期刊类【格式】[序号]作者.篇名[J].刊名，出版年份，卷号（期号）：起止页码.【举例】[1] 王海粟.浅议会计信息披露模式[J].财政研究，2004,21(1)：56-58.[2] 夏鲁惠.高等学校毕业论文教学情况调研报告[J].高等理科教育，2004(1):46-52.[3] Heider, E.R.& D.C.Oliver. The structure of color space in naming and memory of two languages [J]. Foreign Language Teaching and Research, 1999, (3): 62 – 67.2.专著类【格式】[序号]作者.书名[M].出版地：出版社，出版年份：起止页码.【举例】[4] 葛家澍，林志军.现代西方财务会计理论[M].厦门：厦门大学出版社，2001：42.[5] Gill, R. Mastering English Literature [M]. London: Macmillan, 1985: 42-45.3.报纸类【格式】[序号]作者.篇名[N].报纸名，出版日期（版次）.【举例】[6] 李大伦.经济全球化的重要性[N]. 光明日报，1998-12-27(3).[7] French, W. Between Silences: A V oice from China[N]. Atlantic Weekly, 1987-8-15(33).4.论文集【格式】[序号]作者.篇名[C].出版地：出版者，出版年份：起始页码.【举例】[8] 伍蠡甫.西方文论选[C]. 上海：上海译文出版社，1979：12-17.[9] Spivak,G. ―Can the Subaltern Speak?‖[A]. In C.Nelson & L. Grossberg(eds.). Victory in Limbo: Imigism [C]. Urbana: University of Illinois Press, 1988, pp.271-313.[10] Almarza, G.G. Student foreign language teacher’s knowledge growth [A]. In D.Freeman and J.C.Richards (eds.). Teacher Learning in Language Teaching [C]. New York: Cambridge University Press. 1996. pp.50-78.5.学位论文【格式】[序号]作者.篇名[D].出版地：保存者，出版年份：起始页码.【举例】[11] 张筑生.微分半动力系统的不变集[D].北京：北京大学数学系数学研究所, 1983：1-7.6.研究报告【格式】[序号]作者.篇名[R].出版地：出版者，出版年份：起始页码.【举例】[12] 冯西桥.核反应堆压力管道与压力容器的LBB分析[R].北京：清华大学核能技术设计研究院, 1997：9-10.7.条例【格式】[序号]颁布单位.条例名称.发布日期【举例】[15] 中华人民共和国科学技术委员会.科学技术期刊管理办法[Z].1991—06—058.译著【格式】[序号]原著作者. 书名[M].译者，译.出版地：出版社，出版年份：起止页码.三、注释注释是对论文正文中某一特定内容的进一步解释或补充说明。
Effects oftemperature-dependentmaterialpropertiesandshieldinggason
abstract
Laser welding processes are widely used for fabrications in many engineering applications such as aerospace and automotives. In this paper, a moving distributed heat source model based on Goldak’s method [1] has been implemented into finite volume thermal simulations in order to predict temperature distributions during the welding process of a magnesium alloy and to study the effects of variations in thermal properties, absorption coefficient and gas shielding on the computed temperature distributions and weld pool dimensions. The main conclusion is the significant effects of varying the thermal conductivity and absorption coefficient of magnesium. Also, it has been seen that the shielding gas, besides its main role of protection against oxidation, has a significant effect on the width of the weld pool. Finally, the obtained results have been compared to the experimental ones and a satisfactory correlation has been observed, indicating the reliability of the model developed in this study.
到9月9日
到9月9日，社保基金正式进入股市整整3个月，按照有关规定，社保基金必须通过基金管理公司在三个月内完成建仓，并且其持仓市值要达到投资组合总市值80%的水平。
与此前大受追捧的QFII概念相比，社保基金及其所持有的股票显然低调得多，但是在西南证券分析师田磊看来，至少就目前来看，社保基金无论是在资金规模，还是在持股数量上明显都强于境外投资者，其投资理念和行为更可能给市场带来影响。
基金操作的社保基金的选股思路并不侧重某个行业，而更看重企业本身的发展和成长性，并且现阶段的企业经营业绩和走势也不是基金重点考虑的方面。
目前入市的社保基金都是委托南方、博时、华夏、鹏华、长盛、嘉实6家基金管理公司管理。
社保基金大致是被分为14个组合由以上6家管理公司分别管理，每个组合都有一个三位数的代码，第一位代表投资方向，其中“1”指股票投资、“2”指债券投资；第三位数字则代表基金公司名称，其中“1”为南方、“2”为博时、“3”为华夏、“4”为鹏华、“5”为长盛、“6”为嘉实；另有107、108组合主要运作社保基金此前一直持有的中石化股票，分别由博时与华夏基金公司管理。
在许多社保基金介入的股票中经常可以看到开放式基金的身影，例如在被社保基金大量持有的安阳钢铁(600569)的前10大股东中，其第2、6、7、8、9大股东均为开放式基金，而社保基金则以持股500多万股位列第3大股东。
类似的情况也出现在社保基金103组合所持有的华菱管线(000932)上，其第二大股东即为鹏华行业成长证券投资基金，社保基金则以200多万股的持仓量位列第7大股东，此外，在其前10大股东中还有5家是封闭式基金。
对此，某基金公司人士解释说，在获得社保基金管理人资格后，6家基金公司成立了专门的机构理财部门负责社保基金的投资管理，但是其研究、交易系统等则与公募基金共用一个平台，因此社保基金和开放式基金在选股时才会如此一致。
针对“社保概念股”的走势，国盛证券的分析师王剑认为，虽然社保基金此次委托入市资金超过百亿元，但大部分投向是债券，而且由于社保基金的特殊地位，因此基金管理公司对社保基金的操纵策略应该是以“集中持股，稳定股价”为主，不大可能博取太高的收益。
范德堡多晶硅热导率的测试结构
材料与工艺范德堡多晶硅热导率的测试结构Ξ戚丽娜 许高斌 黄庆安(东南大学M E M S教育部重点实验室,南京,210096)2003209219收稿,2003211227收改稿摘要:在O.M.Pau l等研究的范德堡热导率测试结构的基础上,提出了一种改进结构,利用一组测试结构来测得多晶硅薄膜的热导率。
在十字型结构中一个含有多晶硅薄膜,而另一个不含有多晶硅薄膜,根据建立的热学模型,可以获取多晶硅薄膜的热导率。
用有限元分析软件AN SYS进行了模拟分析,分析表明模拟值与实验值能较好地吻合,且辐射散热是基本可以忽略的,从而验证了模型建立的正确性,说明该方法能够实现对多晶硅薄膜的测量,且具有较高的测试精确度。
关键词:范德堡测试结构;热导率;多晶硅薄膜;热响应;十字型中图分类号:TN402;TN405 文献标识码:A 文章编号:100023819(2005)042569205Van D er Pauw Test Structure of the Thermal Conductiv ity ofPolysilicon Th i n F il m sQ I L ina XU Gaob in HU AN G Q ing’an(K ey L abora tory of M EM S of M in istry of E d uca tion,S ou theast U n iversity,N anj ing,210096,CH N)Abstract:A m icrom ach ined therm al V an D er Pauw test structu re is i m p roved.Tw o structu res to m easu re conductivity of po lysilicon th in fil m s are u sed.O ne cro ss2shap ed layers con sists of po lysilicon th in fil m s.T he o ther cro ss2shap ed layers has no po lysilicon th in fil m s. M ak ing u se of the difference betw een the structu res,conductivity of po lysilicon th in fil m can be m easu red.T herm al fin ite elem en t si m u lati on s show that the radiative heat lo ss from the structu re has a negligib le effect on the ex tracted k value.F in ite elem en t softw are AN SYS is u sed to verify the structu re design.Key words:Van D er Pauw test structure;conductiv ity;polysil icon f il m;ther ma l respon se;Greek crossEEACC:2575F;84601 引 言在M E M S和集成电路中,热学效应都是相当重要的,许多传感器也利用热传输来感知其他的物理量。
半导体器件机理 英文
半导体器件机理英文Semiconductor Device Mechanisms.Semiconductors are materials that have electrical conductivity between that of a conductor and an insulator. This unique property makes them essential for a wide range of electronic devices, including transistors, diodes, and solar cells.The electrical properties of semiconductors are determined by their electronic band structure. In a semiconductor, the valence band is the highest energy band that is occupied by electrons, while the conduction band is the lowest energy band that is unoccupied. The band gap is the energy difference between the valence band and the conduction band.At room temperature, most semiconductors have a relatively large band gap, which means that there are very few electrons in the conduction band. This makessemiconductors poor conductors of electricity. However, the electrical conductivity of a semiconductor can be increased by doping it with impurities.Donor impurities are atoms that have one more valence electron than the semiconductor atoms they replace. When a donor impurity is added to a semiconductor, the extra electron is donated to the conduction band, increasing the number of charge carriers and the electrical conductivityof the semiconductor.Acceptor impurities are atoms that have one lessvalence electron than the semiconductor atoms they replace. When an acceptor impurity is added to a semiconductor, the missing electron creates a hole in the valence band. Holes are positively charged, and they can move through the semiconductor by accepting electrons from neighboring atoms. This also increases the electrical conductivity of the semiconductor.The type of impurity that is added to a semiconductor determines whether it becomes an n-type semiconductor (witha majority of electrons as charge carriers) or a p-type semiconductor (with a majority of holes as charge carriers).The combination of n-type and p-type semiconductors is used to create a wide range of electronic devices,including transistors, diodes, and solar cells.Transistors.Transistors are three-terminal devices that can be used to amplify or switch electronic signals. The threeterminals are the emitter, the base, and the collector.In a bipolar junction transistor (BJT), the emitter is an n-type semiconductor, the base is a p-type semiconductor, and the collector is another n-type semiconductor. When a small current is applied to the base, it causes a large current to flow between the emitter and the collector. This makes BJTs ideal for use as amplifiers.In a field-effect transistor (FET), the gate is a metal electrode that is insulated from the channel. When avoltage is applied to the gate, it creates an electricfield that attracts or repels electrons in the channel. This changes the conductivity of the channel, which in turn controls the flow of current between the source and the drain. FETs are ideal for use as switches.Diodes.Diodes are two-terminal devices that allow current to flow in only one direction. The two terminals are the anode and the cathode.In a p-n diode, the anode is a p-type semiconductor and the cathode is an n-type semiconductor. When a voltage is applied to the diode, it causes electrons to flow from the n-type semiconductor to the p-type semiconductor, but not vice versa. This makes diodes ideal for use as rectifiers, which convert alternating current (AC) to direct current (DC).Solar Cells.Solar cells are devices that convert light energy into electrical energy. They are made of a semiconductor material, such as silicon, that has a p-n junction.When light strikes the solar cell, it creates electron-hole pairs in the semiconductor. The electrons areattracted to the n-type semiconductor, while the holes are attracted to the p-type semiconductor. This creates a voltage difference between the two semiconductors, which causes current to flow.Solar cells are used to power a wide range of devices, including calculators, watches, and satellites. They are also used to generate electricity for homes and businesses.Conclusion.Semiconductors are essential for a wide range of electronic devices. Their unique electrical properties make them ideal for use in transistors, diodes, and solar cells. As semiconductor technology continues to develop, we canexpect to see even more innovative and efficient electronic devices in the future.。
半固态等温处理制备非枝晶组织YL112压铸铝合金的研究
收稿日期:2004-03-31; 修订日期:2004-04-07研究项目:重庆市教委应用基础研究项目,编号为:020609作者简介:杨明波(1971- ),重庆南川人,副教授.研究方向:凝固过程数值模拟、轻合金材料及其成形技术.E mail :ymbzcl @s ohu .com半固态等温处理制备非枝晶组织YL 112压铸铝合金的研究杨明波,代 兵,李 晖(重庆工学院材料系,重庆400050)摘要:通过工艺试验和组织分析相结合的办法,对半固态等温处理制备非枝晶组织YL112压铸铝合金进行了初步的研究。
研究结果表明:半固态等温热处理能有效地使YL112压铸铝合金的铸态枝晶组织转变为非枝晶组织,其中提高等温温度有利于合金铸态枝晶组织的熔断和粒状非枝晶组织的形成,而延长保温时间则有利于提高合金粒状非枝晶组织的圆整度。
关键词:半固态等温处理;非枝晶组织;YL112压铸铝合金中图分类号:TG146.2+1;TG113.1 文献标识码:A 文章编号:1000-8365(2004)08-0620-02Research on Producing YL 112Die C asting Aluminum Alloy with UndendriticStructure Using Semi -solid Isothermal TreatmentYANG Ming -bo ,DAI Bing ,LI Hui(Department of Materials Science &Engineerin g ,Chongqing Institute of Technology ,Chongqing 400050,China )A bstract :The producing on YL112die casting aluminum alloy with undendritic structur e using semi -solid isothermal treatmentwas studied by the method of combining the technological experiment with structur e analysis in the paper ,and the effects of semi -solid isother mal temperature ,holding time on the undendritic structure forming of YL112die casting aluminum alloy was also analyzed .The researc h result indicated that the semi -solid isothermal treatment was an efficient way for making YL112die casting aluminum alloy with undritic structure ,and the forming of undendritic structure would become easy with the increasing of the semi -solid isothermal temperature or the holding time .Key words :Semi -solid isother mal treatment ;Undendritic structure ;YL112die casting aluminum alloy 半固态金属成形技术作为一种先进的金属加工技术,因其具有凝固收缩小、偏析小、材料消耗少、节约能源、产品品质较高等优良的特性,被誉为21世纪新一代金属成形技术[1,2]。
Mg-6Zn-1Cu-0.3Mn镁合金的半固态组织演变
2019,Vol.33,No.10 www.mater⁃rep.com huangxf_lut@DOI :10.11896/cldb.18080139基金项目:国家自然科学基金(51464032) This work was financially supported by the National Natural Science Foundation of China (51464032).Mg⁃6Zn⁃1Cu⁃0.3Mn 镁合金的半固态组织演变黄晓锋1,2,,张乔乔1,马亚杰1,魏浪浪1,杨剑桥11 兰州理工大学省部共建有色金属先进加工与再利用国家重点实验室,兰州7300502 兰州理工大学有色金属合金及加工教育部重点实验室,兰州730050采用半固态等温热处理法,研究了重熔温度和等温时间对Mg⁃6Zn⁃1Cu⁃0.3Mn 镁合金半固态组织演变的影响㊂结果表明:在不同温度保温30min 或在585℃保温不同时间的球化演变过程中,Mg⁃6Zn⁃1Cu⁃0.3Mn 合金中球状组织的平均尺寸㊁形状因子均先减小后增大,且固相率明显下降;晶界和亚晶界共同提供了溶质原子的扩散通道和液相相互渗透的路径,晶粒内部的溶质原子Zn ㊁Cu 和Mn 富集区和枝晶壁搭接处形成了高溶质浓度的小 液池”;当保温温度超过585℃或时间超过30min 时,颗粒易于粗化,其粗化符合Ostwald 熟化机制㊂适合Mg⁃6Zn⁃1Cu⁃0.3Mn 合金的半固态等温处理工艺为585℃×30min ,其颗粒平均尺寸㊁形状因子和固相率分别为29.91μm ㊁1.09和47.55%㊂关键词 Mg⁃6Zn⁃1Cu⁃0.3Mn 镁合金 半固态组织 半固态等温热处理 球化演变中图分类号:TG146.22 文献标识码:ASemi⁃solid Microstructure Evolution of Mg⁃6Zn⁃1Cu⁃0.3Mn Magnesium AlloyHUANG Xiaofeng 1,2,,ZHANG Qiaoqiao 1,MA Yajie 1,WEI Langlang 1,YANG Jianqiao 11 State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals,Lanzhou University of Technology,Lanzhou 7300502 Key Laboratory of Non⁃ferrous Metal Alloys and Processing,Ministry of Education,Lanzhou University of Technology,Lanzhou 730050The effects of remelting temperature and holding time for the semi⁃solid microstructure evolution of Mg⁃6Zn⁃1Cu⁃0.3Mn magnesium alloy were studied by semi⁃solid isothermal heat treatment.The results show that with holding temperature and time prolonging,the acceleration of the remelting process and change in the microstructure is acquired,in the process of spherical evolution at different temperatures for 30min or at 585℃for different time.The average size and shape factor of the spherical semi⁃solid microstructure first decrease and then increase,while the solid fraction decreases sharply.The grain boundaries and sub⁃boundaries both provide the solute atoms with diffusion aisles and the liquid phase with interpenetration path,and the liquid pools”of high solute concentration form at the rich Zn,Cu and Mn solute atoms regions and the den⁃drite arms overlap.With the holding temperature exceeding 585℃or the heat preservation time over 30min,the primary particles tend to merge and grow up,consistent with the rule of Ostwald ripening mechanism.The fitting heat treatment parameters is reheating for 30min at 585℃for semi⁃solid isothermal heat treatment of the alloy,and the average particle size,shape factor and solid fraction of the alloy are 29.91μm,1.09and 47.55%,respectively.Key words Mg⁃6Zn⁃1Cu⁃0.3Mn magnesium alloy,semi⁃solid structure,semi⁃solid isothermal heat treatment,spherical evolution0 引言镁合金具有质量轻㊁比强度高㊁比刚度高[1]㊁机械加工性能优良㊁易回收等优点[2],在实现轻量化㊁节能减排等方面有显著的作用[3],其应用前景很可观,被誉为21世纪绿色环保的结构和功能材料[4]㊂但与铝合金相比,其强度㊁蠕变等力学性能还有不足[5]㊂目前,改善镁合金力学性能的方法一般是通过开发新型合金或者改变加工工艺㊂其中,半固态压铸成形技术作为一种新型的加工技术,集全固态和全液态成形的特点于一身;具有金属液以层流方式平稳地充型㊁铸件卷气少㊁材料损耗少㊁凝固收缩小㊁成品质量高㊁节约能源等一系列优点;且较低的成形温度可延长模具的使用寿命,能有效地改善镁合金加工过程中的氧化烧损等浇铸缺点[6⁃10]㊂近年来,半固态等温热处理法制备镁合金半固态坯料因设备简单㊁工艺简化而引起了国内外学者广泛的关注㊂据报道[11],ZAM6301合金经半固态等温热处理后,获得了圆整㊁尺寸小且分布均匀的近球状颗粒;Jiang 等[12]发现用等通道角挤压能够使AZ80合金获得很好的应变诱导效果;Kamado 等[13]研究了Mg⁃Zn⁃Al⁃Ca 合金的半固态成形,认为该合金具有较宽的凝固范围,固相率对温度的敏感性低以及在较低的温度下便可获得细小的固相颗粒;Lyu 等[14]的研究结果表明,在等温热处理过程中,AZ65合金中晶界残留的Mg 17Al 12+Mg 32⁃(Al,Zn)49相优先溶解,进一步提高热处理温度,α⁃Mg 熔化并分离成小块,然后逐渐变成球状颗粒㊂已有的研究虽然可以明确Mg⁃Zn⁃Al 系合金可用于半固体压铸成形,但是该系列合金的热处理强化作用较弱,半固体压铸后,制品无法进行热处理进一步提高力学性能,限制了其在半固体压铸成形领域的应用㊂Mg⁃Zn⁃Cu 系镁合金是20世纪70年代开发的一种新型Mg⁃Zn 系合金,具有较好的热处理强化作用,但目前国内外基于Mg⁃Zn⁃Cu 合金的优化研究尚在起步阶段,报道有限,需要进一步研究[15⁃16],关于Mg⁃Zn⁃Cu 系半固态工艺的研究更少,因此,基于开发适用于半固态成形的高性能新型Mg⁃Zn 系合金,本工作选取了Mg⁃6Zn⁃1Cu⁃0.3Mn 镁合金,通过优化Mg⁃6Zn⁃1Cu⁃0.3Mn 镁合金的半固态组织制备工艺并针对半固态组织演变过程进行了机理分析,希望能为新型半固态镁合金组织的制备及优化提供借鉴㊂半固态材料对微观组织的要求是[17⁃18]:(1)固相颗粒圆整,形状因子接近于1;(2)固相颗粒在半固态材料内部均匀分布,且组织的固相率为40%~60%;(3)固相颗粒细小,平1443均颗粒直径不大于100μm㊂1 实验实验合金的制备原材料是纯度不小于99.9%的Mg㊁Zn 及Cu锭和Mg⁃5%Mn(质量分数)中间合金㊂实验合金采用SG2⁃7.7kW井式电阻炉熔炼,KSW⁃3恒温控制箱控制炉温,用RJ⁃2覆盖熔剂和Ar气氛保护熔体,待Mg锭熔化后,于680℃加入已预热的Zn及Cu锭,700℃时加入Mg⁃5%Mn中间合金,730℃时进行精炼,静置15~20min,待炉温降至710℃时,将熔体浇注于(200±5)℃的金属模具内成形㊂半固态重熔实验于箱式电阻炉(温度误差±2℃)中进行,将合金试样切制成Φ15mm×10mm的圆柱形坯料,分别进行重熔,避免试样被氧化,在其表面撒一层薄RJ⁃2覆盖熔剂进行保护,重熔特定时间后迅速水淬㊂试样经打磨侵蚀后进行微观形貌特征观察㊂用MeF⁃3型金相显微镜和JSM⁃6700F型扫描电镜(SEM)进行半固态组织形貌的观察㊂用X 射线衍射仪(D/max⁃2400)进行合金的物相分析:Cu靶, 40kV的电压,150mA的电流,扫描步长为0.02°㊂用Image⁃Pro Plus软件分析其固相率(S)㊁形状因子(F)和颗粒平均尺寸(D),计算所用的公式为[19]:S=NA i/A s(1) D=[∑2(A i/π)1/2]/N(2) F=(∑P2i/4πA i)/N(3)式中:A i为单个固相颗粒的面积,A s为固相和液相的总面积, N为固相颗粒数量,P i为单个固相颗粒的周长,形状因子F 愈趋近于1,表明得到的固相颗粒越圆整㊂2 结果与分析2.1 铸态显微组织图1和图2分别为铸态Mg⁃6Zn⁃1Cu⁃0.3Mn合金的显微组织形貌和XRD谱㊂由图1a可看出,Mg⁃6Zn⁃1Cu⁃0.3Mn合金组织由白色的等轴α⁃Mg基体和沿晶界分布的黑色共晶组成㊂其中,α⁃Mg基体呈 雪花”状和 蔷薇”状,共晶组织呈孤点状(图1b红圈A所示)和粗大树枝状(图1b红圈B所示)㊂由图1结合图2可得,共晶组织由(α⁃Mg+CuZn2+ CuMgZn+CuMnZn)组成㊂在共晶组织中,因溶质原子Zn含量较高,其形成的化合物富集于枝晶边界处,呈树枝状分布;弥散的孤立点状相是Mn颗粒及其化合物(CuMnZn)[20]㊂在非平衡凝固过程中,当温度降至液相线温度时会析出α⁃Mg基体,当温度继续降至共晶温度点时,共晶组织(α⁃Mg+图1 Mg⁃6Zn⁃1Cu⁃0.3Mn合金的铸态显微组织Fig.1 As⁃cast microstructures of the Mg⁃6Zn⁃1Cu⁃0.3Mnalloy图2 Mg⁃6Zn⁃1Cu⁃0.3Mn铸态合金的XRD谱Fig.2 XRD pattern of the as⁃cast Mg⁃6Zn⁃1Cu⁃0.3Mn alloyCuZn2+CuMgZn+CuMnZn)沿α⁃Mg基体边界析出,同时剩余的溶质原子富集在枝晶根部[21]㊂2.2 半固态组织演变2.2.1 保温温度对半固态组织的影响图3和图4分别为Mg⁃6Zn⁃1Cu⁃0.3Mn合金在不同的温度下保温30min的半固态组织演变规律及其半固态组织的颗粒平均尺寸㊁形状因子和固相率随保温温度的变化关系曲线㊂由图3a可知,在570℃保温时,原铸态枝晶组织基本消失,取而代之的是不规则且紧密相连的白色块状组织,其平均尺寸为51.87μm,固相率高达72.67%,形状因子为1.72(见图4),不规则初生颗粒内分布着形状各异的小 液池”㊂随着保温温度的升高,块状组织逐渐演变为椭圆状颗粒,液相明显增多,颗粒开始彼此分离并逐渐趋于圆整,且颗粒上点状小 液池”数量增加,组织的固相率分别为65.41%和56.32%,颗粒平均尺寸分别为46.39μm和38.99μm,形状因子分别为1.54和1.51(见图3b㊁c和图4)㊂在585℃保温时,如图3d所示,半固态组织呈球状或近球状,固相和液相组织均匀分布,固相颗粒尺寸和形状因子最小,分别为29.91μm和1.09,其固相率为47.55%(见图4)㊂当温度升高至590℃时,其固相率为38.94%,颗粒圆整度变差,形状因子有所增加,这是相邻颗粒的合并长大所致㊂当温度继续升至595℃时,Mg⁃6Zn⁃1Cu⁃0.3Mn合金的液相含量增加为66.9%㊂由图4可知,保温时间不变,随保温温度的升高,半固态组织的固相率一直呈下降趋势,颗粒平均尺寸和形状因子都呈先降低后增加的趋势㊂这符合Ostwald熟化机制[19],在过饱和固溶体析出的后期,为了降低体系界面能,较小颗粒消失,而较大颗粒长大,相邻晶粒合并,因而平均尺寸增大(见图4)㊂对于半固态合金的形状因子先减小后增大的规律,张少辉和冯凯等[22⁃23]研究认为是由于保温前期枝晶臂的熔断和消失使得形状因子减小;在保温后期,初生颗粒边沿出现了 毛刺”状组织,且颗粒合并长大,这共同影响了其形状因子,使得形状因子变大㊂在特定保温时间下,随着保温温度的升高,枝晶熔断消失,无规则块状组织逐渐演变为球状和近球状颗粒㊂对于半固态组织的这种变化规律,李元东等[24]研究发现,随着保温温度的升高,颗粒的晶内成分会均化,固溶度提高;其次,不同枝晶的曲率不同,致使枝晶周围溶质浓度存在差别,半径小的枝晶周围溶质浓度较低,导致枝晶间存在溶质浓度梯度㊂这满足溶质原子的扩散理论,故半径相异的两枝晶间2443材料导报(B),2019,33(10):3441⁃3447(一次枝晶与二次枝晶间)会形成一个扩散偶,不同浓度的溶质原子在化学势作用下从粗大枝晶处向细小枝晶处扩散,造成细枝熔化或从根部熔断;在凝固过程中,由于共晶组织的成分不同,溶质浓度高的区域熔点低,低熔点相后凝固而存在晶粒之间,重熔时这些组织优先熔化㊂图3 Mg⁃6Zn⁃1Cu⁃0.3Mn 合金在不同温度下保温30min 的半固态组织:(a)570℃;(b)575℃;(c)580℃;(d)585℃;(e)590℃;(f)595℃Fig.3 Semi⁃solid microstructure of the Mg⁃6Zn⁃1Cu⁃0.3Mn alloy treated at different temperatures for 30min:(a)570℃;(b)575℃;(c)580℃;(d)图4 Mg⁃6Zn⁃1Cu⁃0.3Mn 合金在不同温度保温30min 的颗粒平均尺寸㊁形状因子和固相率Fig.4 Particlesize,shape factor and solid fraction of the Mg⁃6Zn⁃1Cu⁃0.3Mn alloy treated at different temperatures for 30min2.2.2 保温时间对半固态组织的影响基于以上的分析,Mg⁃6Zn⁃1Cu⁃0.3Mn 合金在585℃保温30min 的半固态组织分布均匀,颗粒尺寸较小,且形状因子接近于理想的1,因此选择保温温度在585℃来探究不同保温时间对半固态组织演变的影响㊂图5和图6分别是等温时间对Mg⁃6Zn⁃1Cu⁃0.3Mn 合金半固态组织演变的影响规律以及合金平均颗粒尺寸㊁形状因子及固相率随保温时间的变化曲线㊂由图5a 可以看出,保温5min 时,少量液相分布于不规则的α⁃Mg 颗粒周围,且不同晶粒间已经有明显分离的趋势;保温10min 时,共晶组织向α⁃Mg 基体中固溶,枝晶臂熔断,组织呈不规则大块状,这是由于曲率较大的二次枝晶臂经过传热和传质被熔断,与主干组织分离㊂如图5b 所示,有少许液相出现,同时初生颗粒内点缀着小 液池”;保温20min 时,组织中已经出现了较多的液相,且α⁃Mg 基体演变为椭球状颗粒,其平均尺寸㊁形状因子分别为48.46μm 和1.50(见图5c 和图6);保温30min 时,组织呈近球状颗粒,颗粒平均尺寸和形状因子分别为29.91μm 和1.09,固相率为47.55%(见图5d 和图6),颗粒尺寸细小,分布均匀且最圆整,因而Mg⁃6Zn⁃1Cu⁃0.3Mn 合金在585℃保温30min 时,可获得理想的半固态颗粒㊂当保温时间进一步延长时,颗粒平均尺寸及形状因子均明显增加,依次为41.24μm 和42.38μm 图5 Mg⁃6Zn⁃1Cu⁃0.3Mn 合金在585℃下保温不同时间的半固态组织:(a)5min;(b)10min;(c)20min;(d)30min;(e)40min;(f)50min Fig.5 Semi⁃solid microstructure of the Mg⁃6Zn⁃1Cu⁃0.3Mn alloy treated at585℃for different time:(a)5min;(b)10min;(c)20min;(d)30min;图6 Mg⁃6Zn⁃1Cu⁃0.3Mn 合金在585℃保温不同时间的颗粒平均尺寸㊁形状因子和固相率Fig.6 Particle size,shape factor and solid fraction of the Mg⁃6Zn⁃1Cu⁃0.3Mn alloy treated at 585℃for different time3443Mg⁃6Zn⁃1Cu⁃0.3Mn 镁合金的半固态组织演变/黄晓锋等及1.41和1.34(见图5e㊁f和图6),这是由于初生α⁃Mg的合并长大使颗粒尺寸和形状因子增大㊂对于通过保温热处理获取非枝晶组织的这种演变规律,冯凯等[23]研究认为在高温保温处理时,块状组织间存在的亚晶界为颗粒演变提供了驱动力,促进了组织的分离和球化演变;张玉等[19]研究认为,高温保温时间过长时,大颗粒会吞并小颗粒,使得颗粒平均尺寸急剧增加,同时液相也得以增加㊂2.3 非枝晶组织的特征与小 液池”为进一步确定Mg⁃6Zn⁃1Cu⁃0.3Mn合金半固态组织的相成分和组织特征,采用SEM及配套的EDS对585℃×30min 的试样进行分析,图7为合金的显微组织㊂由图7a左下角的光学显微组织可以看出,半固态组织由白色初生α1⁃Mg颗粒㊁次生等轴α2⁃Mg小颗粒以及黑色的共晶液相组成,分别对应于图7a右上方SEM显微组织,红色箭头标示出了组织的形貌:共晶组织和α2⁃Mg整体呈蜂窝状镶嵌于α1⁃Mg周围(图7a中的红圈标示),A处为白色点状,是因Zn㊁Cu和Mn 富集优先熔化而形成的小 液池”,B为初生α1⁃Mg颗粒,C 处为共晶液相,D处蜂窝眼为次生等轴α2⁃Mg颗粒㊂由图7b 可得,α2⁃Mg颗粒均匀分布于α1⁃Mg周围㊂结合EDS分析可知(见表1),α2⁃Mg中Mg含量明显下降,溶质Zn和Cu含量上升,研究[23]表明:在保温处理过程中,重熔和结晶是动态平衡的过程,α1⁃Mg晶界处的溶质浓度较高因此优先熔化,重熔时,溶质原子会再次发生固溶,致使次生组织中Zn和Cu含量增加㊂Zhang等[25]认为,初生共晶组织在等温重熔过程中,原子获得足够的能量,且固溶过程中增加了空位,这有利于长程扩散而形成了前面描述的结果㊂也可能是在浇注时的快速冷凝过程中形成了中间相亚稳相和空位,保温重熔时,亚稳相优先熔化,空位因不稳定而易迁移至初生相边界,重熔时溶质原子固溶到空位中,故二次凝固组织中溶质Zn 和Cu浓度比初生组织中偏高[26]㊂对图7c进行EDS分析结果如表2所示,点A㊁B处的Zn和Cu含量比点C㊁D和E㊁F 处高,这可能是共晶晶界处溶质含量比基体高,因而熔点较低,在重熔时优先熔化,但Mg基体因熔点高而未熔,阻挡了溶质原子的流动扩散通道,在水淬后以 液池”状存在;也可能是在重熔时,溶质原子富集区因枝晶包裹而无法扩散,使得A处的Zn和Cu含量偏高㊂与初生α1⁃Mg基体(F点)相比,边沿处(C㊁D点)的Zn㊁Cu含量高(见图7c和表2),冯凯等[23]认为是初生共晶组织晶界处高浓度的共晶组织在保温过程中优先熔化,水淬时会有部分溶质原子固溶到基体所致㊂初生基体的溶质浓度最低,是因为其在重熔时会向液相偏析出,越靠近初生基体边沿直至蜂窝共晶组织时,溶质含量依次升高㊂初生半固态颗粒的形成如图7d所示,在保温过程中,枝晶根部会优先熔化,出现 颈缩”甚至熔断(见图7d红色圈出部分标示),最终形成α1⁃Mg颗粒㊂ 液池”的存在和扩展也是大颗粒分离成小颗粒的主要方式之一,其形成归因于以下两方面[26⁃27]:一是晶粒内部的Cu㊁Zn和Mn富集区在重熔时优先熔化形成小 液池”;二是在保温热处理初期,枝晶壁搭接处的共晶相在重熔时转化为小 液池”㊂如图7f所示,因成分偏析和能量起伏的存在,在重熔过程中, 液池”依次按A⁃B⁃C⁃D的过程扩展和长大,随保温时间的延长, 液池”继续扩展变大,当相邻 液池”增大到相互搭接时,大颗粒会裂解成较小颗粒(图7e的红圈标示)㊂表1 图7b中α1⁃Mg和α2⁃Mg的EDS分析结果Table1 EDS analysis results ofα1⁃Mg andα2⁃Mg in Fig.7bPhase Atomic ratio/%Mg Zn Cu Mn α1⁃Mg99.20.800α2⁃Mg95.83.50.70表2 图7c中各点的EDS分析结果Table2 EDS analysis results of points in Fig.7cPoint Atomic ratio/%Mg Zn Cu Mn A75.519.450.1B82.214.43.40C85.111.730.2D90.97.61.50E92.56.31.20F99.20.80图7 半固态Mg⁃6Zn⁃1Cu⁃0.3Mn合金在585℃保温不同时间的显微组织:(a c㊁e)30min;(d)5min;(f)3min㊁5min㊁10min和30min(电子版为彩图)Fig.7 Semi⁃solid microstructure of the Mg⁃6Zn⁃1Cu⁃0.3Mn alloy treated at 585℃for different time:(a c,e)30min;(d)5min;(f)3min, 5min,10min and30min3 等温热处理过程非枝晶组织演变机理分析3.1 保温初期枝晶粗化阶段共晶组织的固溶和溶质原子的扩散共同促进了半固态组织的形成㊂改变等温温度或等温时间,Mg⁃6Zn⁃1Cu⁃0.3Mn 合金枝晶组织在界面能降低的驱动下发生了重熔,重熔初期,因相起伏㊁能量起伏及浓度起伏的存在,提高了溶质原子的扩散能力,故均质扩散占主导地位,此时晶界处Zn㊁Cu和Mn原子向两侧扩散;因存在温度梯度,合金内部的空位会合并,位错发生攀移;合金熔体内剪切应力的存在使枝晶臂根部产生应力,诱发小角度晶界[23]㊂这共同促进固溶体的形成4443材料导报(B),2019,33(10):3441⁃3447和共晶的分解㊁枝晶臂熔断消失,α⁃Mg 基体尺寸明显膨胀增加,近球形㊁花瓣状和蔷薇状组织出现(见图8)㊂图8 Mg⁃6Zn⁃1Cu⁃0.3Mn 合金在585℃保温3min 的显微组织Fig.8 Microstructure of the Mg⁃6Zn⁃1Cu⁃0.3Mn alloy treated at 585℃for 3min3.2 非枝晶组织的分离及分离后的形貌在保温初期,枝晶间的大角度晶界以及浓度起伏和局部应力的变化促成的小角度晶界,共同成为溶质原子相互渗透的路径,加速α⁃Mg 颗粒的分离[28]㊂如图9所示,黑色箭头标示的晶界和红色圈圈出的亚晶界,共同提供了Zn㊁Cu 和Mn 渗透的路径,加速了Mg⁃6Zn⁃1Cu⁃0.3Mn 半固态颗粒的分离;枝晶根部的溶质浓度较高,会降低合金局部熔点,促进局部熔断,有利于大颗粒之间的分离㊂图9 Mg⁃6Zn⁃1Cu⁃0.3Mn 合金在585℃保温3min 的显微组织Fig.9 Microstructure of the Mg⁃6Zn⁃1Cu⁃0.3Mn alloy treated at 585℃for 3min图10 Mg⁃6Zn⁃1Cu⁃0.3Mn 合金在585℃保温不同时间的显微组织:(a)5min;(b)10min;(c)20minFig.10 Microstructure of the Mg⁃6Zn⁃1Cu⁃0.3Mn alloy treated at 585℃for different time:(a)5min;(b)10min;(c)20min保温初期,颗粒间的边界轮廓出现后,边界上会出现如图10a 所示红圈标示的类似于 焊缝”的组织,随保温时间的延长,颗粒开始分离,这些 焊缝”演变成 小枝”(见图10b 红圈所示),进一步长大成 长枝”(见图10c 红圈所示),分布于初生α⁃Mg 颗粒周围㊂对于这些组织演变,由凝固热力学可知,存在固⁃液界面张力时,颗粒表面固相平衡熔点和颗粒曲率半径有关,平衡熔点随曲率变化的关系式为[29]:ΔT r =-2σT m V s k ΔH m(4)式中:σ为固⁃液界面张力,T m 为固⁃液界面的熔点,V s 为固相摩尔体积,ΔH m 为固⁃液转变时的摩尔焓变,k 为固⁃液界面曲率㊂曲率越小,熔点越低,在二次加热时易于熔化,故在重熔时,颗粒表面凸起处优先熔化㊂3.3 固相颗粒的合并㊁熟化在保温后期,半固态颗粒发生 长大”,主要是由于半固态颗粒处于动态平衡,当固相率较高时,颗粒之间会发生合并,液相率较高时,颗粒处于游离状,小颗粒会发生游离和碰撞,系统为了降低界面能,这些小颗粒或熔化或聚集,促使大颗粒长大㊂颗粒间的合并依赖于颗粒晶体学取向[21],如图11中标示的4与5颗粒㊁6与7颗粒,这种合并更趋于降低体系界面能,也导致颗粒的长大㊂如图11红圈标示的是几个颗粒团聚在一起发生同时合并的现象,类似于标示1㊁2和3颗粒更易于同时合并为一个晶粒,这也有利于降低系统的能量[28]㊂图11 Mg⁃6Zn⁃1Cu⁃0.3Mn 合金585℃保温50min 的显微组织Fig.11 Microstructure of the Mg⁃6Zn⁃1Cu⁃0.3Mn alloy treated at 585℃for 50min在特定温度下,保温时间延长到合金处于固⁃液平衡状态时,界面能的降低只能通过颗粒的合并来实现,这主要是Ostwald 熟化,即[30]:D t 3-D 03=Kt(5)式中:D t 为t 时刻的晶粒平均尺寸,D 0为颗粒原始尺寸,K 为粗化常数㊂对Mg⁃6Zn⁃1Cu⁃0.3Mn 合金在585℃下保温30~50min 的颗粒尺寸采用上述机制进行拟合,结果完全符合该机制,如图12所示㊂合金在585℃保温30min 和50min 时,合金的固相率分别为47.55%和33.21%,粗化系数K 分别为226623μm /min 和306365μm /min,颗粒平均尺寸为29.91μm 和42.38μm(见图6)㊂当合金固相率低于50%时,随固相率的减小,粗化系数也在减小,但颗粒平均尺寸在增大㊂颗粒平均尺寸较小时,其比表面积也较小,界面能高,固⁃液界面处于亚稳状态,在延长保温时间时,为降低界面能,颗粒会熔化甚至消失,溶质原子通过扩散和迁移至大晶粒表面沉积,故晶粒会 变大”,平均尺寸会增加㊂5443Mg⁃6Zn⁃1Cu⁃0.3Mn 镁合金的半固态组织演变/黄晓锋等综上所述,在半固态等温重熔过程中,Mg⁃6Zn⁃1Cu⁃0.3Mn合金主要经历以下三个阶段:(1)初始枝晶粗化阶段㊂由于部分重熔过程是在界面能降低的驱动下完成的,升温初期,整个体系存在相起伏㊁能量起伏以及浓度起伏,使得溶质原子的扩散能力提高,从而使得晶界处溶质向两侧扩散,促进合金的熔解㊁枝晶消失,α⁃Mg基体尺寸增加,出现块状组织㊂(2)中期组织分离㊁球化阶段㊂随着保温时间的延长或者保温温度的升高,由于界面能的存在,扩散持续进行且使得块状颗粒分离㊁趋于球化㊂(3)后期颗粒熟化㊁合并长大阶段㊂在保温后期,因液相的存在,小颗粒会发生移动和碰撞,系统为了降低界面能,使得小颗粒逐渐熔化或者被大颗粒吞并,促使大颗粒长大,液相增多,从而降低了体系能量㊂图12 Mg⁃6Zn⁃1Cu⁃0.3Mn合金D t3-D03与保温时间的关系Fig.12 D t3-D03versus holding time of the Mg⁃6Zn⁃1Cu⁃0.3Mn alloy 4 结论(1)Mg⁃6Zn⁃1Cu⁃0.3Mn合金的铸态组织由白色α⁃Mg基体和黑色(α⁃Mg+CuZn2+CuMgZn+CuMnZn)共晶组织组成,其中,呈孤点状和树枝状的共晶组织分布在晶界处;Mg⁃6Zn⁃1Cu⁃0.3Mn合金的半固态组织主要由初生α1⁃Mg大颗粒㊁次生α2⁃Mg小颗粒和共晶液相构成㊂(2)Mg⁃6Zn⁃1Cu⁃0.3Mn合金经585℃×30min的半固态等温热处理,可获得细小㊁均匀分布且呈球状的理想半固态颗粒,其颗粒平均尺寸㊁形状因子㊁固相率分别为29.91μm㊁1.09和47.55%㊂在不同温度保温30min或在585℃保温不同时间的过程中,随着温度升高或保温时间的延长,合金的半固态颗粒平均尺寸㊁形状因子均先减小后增大,组织的固相率明显下降㊂(3)在半固态等温热处理过程中,晶界和亚晶界共同提供了溶质原子的扩散通道和液相相互渗透的路径;晶粒内部的溶质原子Zn㊁Cu和Mn富集区和枝晶壁搭接处形成了高溶质浓度的小 液池”㊂(4)在重熔⁃结晶的球化演变过程中,Mg⁃6Zn⁃1Cu⁃0.3Mn 合金的枝晶臂熔断消失,水淬后形成次生α2⁃Mg固溶体和共晶液相;其圆整光滑的初生半固态颗粒由枝晶组织转变而来;保温时间为30min不变,温度由575℃升高到585℃时,其颗粒形状因子由1.54降至1.09,半固态组织加速了球化演变;在585℃保温40min和50min时,颗粒平均尺寸分别为41.24μm和42.38μm,颗粒间发生了合并长大和熟化现象,其粗化符合Ostwald熟化机制㊂参考文献1 Fan Z,Liu G,Wang Y.Journal of Materials Science,2006,41(12), 3631.2 Nami B,Shabestari S G,Miresmaeili S M,et al.Journal of Alloys& Compounds,2010,489(2),570.3 Decker R F.Advanced Materials&Processes,1998,154(3),31.4 Mordike B L,Ebert T.Materials Science and Engineering A,2001,302 (1),37.5 Liu W,Yang D D,Quan G F,et al.Rare Metal Materials and Enginee⁃ring,2016,45(8),1967(in Chinese).刘伟,杨豆豆,权高峰,等.稀有金属材料与工程,2016,45(8), 1967.6 Yang B M,Pan F S,Chen R J.et al.Transactions of Nonferrous Metals Society of China,2008,18,566.7 Zhang Y,Huang X F,Ma Y,et al.China Foundry,2017,14,85. 8 Zhang Y,Huang X F,Ma Y,et al.China Foundry,2017,14,251. 9 Nami B,Shabestari S G,Miresmaeili S M,et al.Journal of Alloys& Compounds,2010,489,570.10Qin M L.Effect of heat treatment on Mg⁃x Zn alloy and its semi⁃solid wa⁃ter quenching structure.Master’s Thesis,Lanzhou University of Techno⁃logy,China,2016(in Chinese).秦牧岚.热处理对Mg⁃x Zn合金及其半固态水淬组织的影响.硕士学位论文,兰州理工大学,2016.11Zhang Y.Study on microstructure,properties and strengthening mecha⁃nism of new Mg⁃Zn⁃Al⁃Sm/Mn magnesium alloy.Ph.D.Thesis,Lanzhou University of Technology,China,2018(in Chinese).张玉.新型Mg⁃Zn⁃Al⁃Sm/Mn镁合金的组织㊁性能及其强化机理研究.博士学位论文,兰州理工大学,2018.12Jiang J F,Wang Y,Du Z M,et al.Transactions of Nonferrous Metals So⁃ciety of China,2012,22(s2),s422.13Kamado S,Ikeya N,Rudi R S,et al.Materials Science Forum,2000, 350,205.14Lv Z,Xing J,Ma S,et al.In:The12th China⁃Russia Symposium on Advanced Materials and Technologies.2013.pp.135.15Wang B F,Huang X F,Feng K,et al.China Foundry Machinery& Technology,2012(1),10(in Chinese).王鹏飞,黄晓锋,冯凯,等.中国铸造装备与技术,2012(1),10. 16Behdad S,Zhou L,Henderson H B,et al.Materials Science&Enginee⁃ring A,2016,651,854.17An R.Non⁃ferroue Matals&Rare Earth,2011(4),11(in Chinese).安然.有色金属与稀土应用,2011(4),21.18Wang S L.Research on solid volume fraction detection of semi⁃solid mag⁃nesium alloy.Master’s Thesis,Dalian Jiaotong University,China,2009 (in Chinese).王胜良.半固态镁合金固相体积分数检测技术研究.硕士学位论文,大连交通大学,2009.19Zhang Y,Huang X F,Ma Y,et al.Material Review B:Research Papers. 2018,32(4),1283(in Chinese).张玉,黄晓锋,马颖,等.材料导报:研究篇,2018,32(4),1283. 20Zhang D F,Qi F G,Shi G L,et al.Rare Metal Materials and Enginee⁃ring,2010,39(1),2204(in Chinese).张丁非,齐福刚,石国梁,等.稀有金属材料与工程,2010,39(1), 2204.21Feng K,Huang X F,Ma Y,et al.The Chinese Journal of Nonferrous Metals,2013(3),635(in Chinese).冯凯,黄晓锋,马颖,等.中国有色金属学报,2013(3),635. 22Zhang S H.Study on partial remelting microstructure of Mg⁃x Cu magne⁃sium alloy.Master’s Thesis,Lanzhou University of Technology,China, 2016(in Chinese).张少辉.Mg⁃x Cu镁合金部分重熔组织研究.硕士学位论文,兰州理工大学,2016.23Feng K,Huang X F,Ma Y,et al.The Chinese Journal of Nonferrous Metals,2013,23(11),3039(in Chinese).冯凯,黄晓锋,马颖,等.中国有色金属学报,2013,23(11), 3039.24Li Y D,Hao Y,Chen T J,et al.The Chinese Journal of Nonferrous Metals,2002,12(6),1143(in Chinese).6443材料导报(B),2019,33(10):3441⁃3447。
半导体一些术语的中英文对照
半导体一些术语的中英文对照离子注入机ion implanterLSS理论Lindhand Scharff and Schiott theory 又称“林汉德-斯卡夫-斯高特理论”。
沟道效应channeling effect射程分布range distribution深度分布depth distribution投影射程projected range阻止距离stopping distance阻止本领stopping power标准阻止截面standard stopping cross section 退火annealing激活能activation energy等温退火isothermal annealing激光退火laser annealing应力感生缺陷stress-induced defect择优取向preferred orientation制版工艺mask-making technology图形畸变pattern distortion初缩first minification精缩final minification母版master mask铬版chromium plate干版dry plate乳胶版emulsion plate透明版see-through plate高分辨率版high resolution plate, HRP超微粒干版plate for ultra-microminiaturization 掩模mask掩模对准mask alignment对准精度alignment precision光刻胶photoresist又称“光致抗蚀剂”。
负性光刻胶negative photoresist正性光刻胶positive photoresist无机光刻胶inorganic resist多层光刻胶multilevel resist电子束光刻胶electron beam resistX射线光刻胶X-ray resist刷洗scrubbing甩胶spinning涂胶photoresist coating后烘postbaking光刻photolithographyX射线光刻X-ray lithography电子束光刻electron beam lithography离子束光刻ion beam lithography深紫外光刻deep-UV lithography光刻机mask aligner投影光刻机projection mask aligner曝光exposure接触式曝光法contact exposure method接近式曝光法proximity exposure method光学投影曝光法optical projection exposure method 电子束曝光系统electron beam exposure system分步重复系统step-and-repeat system显影development线宽linewidth去胶stripping of photoresist氧化去胶removing of photoresist by oxidation等离子［体］去胶removing of photoresist by plasma 刻蚀etching干法刻蚀dry etching反应离子刻蚀reactive ion etching, RIE各向同性刻蚀isotropic etching各向异性刻蚀anisotropic etching反应溅射刻蚀reactive sputter etching离子铣ion beam milling又称“离子磨削”。
网络修饰体对铝硅酸盐系玻璃微观结构的影响:第一性原理分子动力学模拟
网络修饰体对铝硅酸盐系玻璃微观结构的影响：第一性原理分子动力学模拟龚海明;宋斌;赵高凌;汪建勋;韩高荣【摘要】Aluminosilicate glass plays an important role in the glass industry, due to its good chemical stability, mechanical strength, and low coefficient of expansion. The microstructure of aluminosilicate glass with different network modifier cations were studied by ab-initio molecular dynamic simulations. It is found that when the modifier cations M/Al=1/2 orR/Al=1(M=Ca2+、Mg2+, R=K+、Na+),aluminium atoms have almost transformed into [AlO4] tetrahedrons, but there is a certain number ofnon-bridging oxygens existed, which is not consistent with previous theory. Based on the analysis of the radial distribution function, the bond angle distribution, coordination number and Qnetc., the effects of local environmental properties of Si/Al from network modifier are discussed. The results show that the electric field strength(z/r2) of the network modifier is the main factor influencing the microstructure of aluminosilicate glass. When the network modifier provides free oxygen to break up the network, it also has the effect of attracting broken bonds, and the stronger the electric field is, the stronger the accumulation is, and the better the coherence of the network.%铝硅酸盐玻璃体系是玻璃工业中的重要体系,具有较好的化学稳定性、较高的机械强度和低膨胀系数.本文采用第一性原理分子动力学模拟研究了几种网络修饰体对铝硅酸盐系玻璃的微观结构的影响,研究发现当M/Al=1/2(M=Ca,Mg)或者R/Al=1(R=Na,K)时,铝全部转变为铝氧四面体,此时玻璃结构并不像传统理论认为的形成一个完整的三维网络,而是存在一定数量的非桥氧.通过对径向分布函数,键角分布、配位数、Qn等方面的分析,讨论了网络修饰体的性质对Si以及Al的局部环境的影响.研究表明网络修饰体的电场强度(z/r2)是影响铝硅酸盐玻璃微观结构的主要因素.网络修饰体在提供游离氧使网络解聚的同时,还有积聚断键的作用,并且电场强度越大,积聚作用越强,网络的连贯性越好.【期刊名称】《燕山大学学报》【年(卷),期】2018(042)002【总页数】6页(P134-139)【关键词】铝硅酸盐玻璃;网络修饰体;第一性原理分子动力学模拟;微观结构【作者】龚海明;宋斌;赵高凌;汪建勋;韩高荣【作者单位】浙江大学材料科学与工程学院,浙江杭州310027;硅材料国家重点实验室,浙江杭州310027;硅材料国家重点实验室,浙江杭州310027;浙江大学物理系,浙江杭州310027;浙江大学材料科学与工程学院,浙江杭州310027;硅材料国家重点实验室,浙江杭州310027;浙江大学材料科学与工程学院,浙江杭州310027;硅材料国家重点实验室,浙江杭州310027;浙江大学材料科学与工程学院,浙江杭州310027;硅材料国家重点实验室,浙江杭州310027【正文语种】中文【中图分类】TQ171.1+10 引言铝硅酸盐玻璃是玻璃工业中的重要体系，具有较好的化学稳定性，较高的机械强度，低膨胀系数。
第八章半导体表面与MIS结构
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第八章 半导体表面与MIS结构
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第八章 半导体表面与MIS结构
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第八章 半导体表面与MIS结构
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耐盐型太阳能驱动界面光热材料及蒸发器的研究进展
化工进展Chemical Industry and Engineering Progress2023 年第 42 卷第 7 期耐盐型太阳能驱动界面光热材料及蒸发器的研究进展李吉焱，景艳菊，邢郭宇，刘美辰，龙永，朱照琪（兰州理工大学石油化工学院，甘肃 兰州 730050）摘要：太阳能驱动界面蒸发技术（SDIE ）依靠光热材料和蒸发器进行海水淡化，因光热转换效率高、环境友好、制造工艺简单和材料丰富等优点引起了学者们的广泛关注。
但在海水淡化过程中，光热材料和蒸发器表面盐结晶的积累会直接影响太阳能界面蒸发效率，解决光热材料和蒸发器表面盐结晶问题是SDIE 中重要的一步。
本文简述了近年来耐盐型光热材料及蒸发器的设计理念与研究现状，阐述了不同耐盐设计的优点和局限性，梳理了其耐盐机制和性能，分析表明通过调控光热材料的孔结构、亲-疏水性、离子基团等方法可以增强光热材料的耐盐性，通过调控盐溶液的浓度和盐的结晶位置等可设计多种耐盐型蒸发器，讨论了目前在SDIE 中解决盐结晶问题存在的共性问题并提出未来的研究挑战，以推进未来SDIE 的研究与发展。
关键词：太阳能；界面蒸发；海水淡化；光热材料；耐盐中图分类号：TQ09 文献标志码：A 文章编号：1000-6613（2023）07-3611-12Research progress and challenges of salt-resistant solar-driven interfacephoto-thermal materials and evaporatorLI Jiyan ，JING Yanju ，XING Guoyu ，LIU Meichen ，LONG Yong ，ZHU Zhaoqi(School of Petrochemical Technology, Lanzhou University of Technology, Lanzhou 730050, Gansu, China)Abstract: Solar-driven interfacial evaporation (SDIE), which relies on photothermal materials and evaporators for desalination, has attracted widespread attention from scholars because of its high photothermal conversion efficiency, environmental friendliness, simple manufacturing process and abundant materials. Addressing the salt crystal buildup on the surface of photothermal materials and evaporators is a crucial stage in SDIE because it will directly affect the evaporation efficiency throughout the desalination process. This paper briefly described the design concepts and research status of salt-tolerant photothermal materials and evaporators in recent years, illustrated the advantages and limitations of different salt-tolerant designs, and sorted out their salt-tolerance mechanisms and performance. The analysis demonstrated that the salt resistance of photothermal materials can be enhanced by regulating the pore structure, hydrophilic-hydrophobic and ionic groups of photothermal materials. A variety of salt-resistant evaporators can be designed by regulating the concentration of salt solution and the crystallization position of salt. In addition, common problems in solving salt crystallization problems in SDIE were discussed and future research challenges were proposed to advance the future research and development of SDIE.Keywords: solar energy; interfacial evaporation; desalination; photothermal materials; salt resistance综述与专论DOI ：10.16085/j.issn.1000-6613.2022-1732收稿日期：2022-09-16；修改稿日期：2022-10-13。
孔隙率对五元陶瓷体系材料热导率的影响
孔隙率对五元陶瓷体系材料热导率的影响陈宇慧*, 姜鹏洋, 张若琳, 孙家祥, 张百强, 张永海（郑州轻工业大学 能源与动力工程学院, 郑州 450000）摘要：随着航空航天技术的发展，热端部件防护材料也需要满足更高的要求。
本工作基于固相反应法和分子动力学模拟研究（Zr x Y（1-x/4）Ta（1-x/4）Ti（1-x/4）Er（1-x/4））O（x=0.2、0.544、0.672、0.796和0.92）五元陶瓷体系复合材料。
采用ZrO2（99.99%）、Y2O3（99.99%）、Ta2O5（99.99%）、Er2O3（99.99%）和TiO2（99%）粉末作为原料，通过固相反应法制备（Zr x Y（1-x/4）Ta（1-x/4）Ti（1-x/4）Er（1-x/4））O复合材料。
用LAMMPS程序计算研究 （Zr x Y（1-x/4）Ta（1-x/4）Ti（1-x/4）Er（1-x/4））O陶瓷材料的导热性能。
结果表明：在200～900 ℃区间时通过实验和模拟获得的热导率变化趋势一致，当x=0.796时热导率均达到最小值，证明了分子动力学模拟多元陶瓷材料热导率的可行性；同时研究了孔隙对热导率的影响，发现元素配比与孔隙对热导率的影响存在一定的竞争关系。
当孔隙率大于6.67%时，孔隙率为主要影响因素，当孔隙率小于6.67%时，元素配比为热导率的主导因素。
关键词：陶瓷材料；分子动力学；热导率；孔隙率doi：10.11868/j.issn.1005-5053.2022.000067中图分类号：TB33 文献标识码：A 文章编号：1005-5053(2023)02-0066-09Effect of porosity on thermal conductivity of quintuple elementceramic system materialsCHEN Yuhui*, JIANG Pengyang, ZHANG Ruolin, SUN Jiaxiang, ZHANG Baiqiang, ZHANG Yonghai （School of Energy and Power Engineering, Zhengzhou University of Light Industry, Zhengzhou 450000, China）Abstract: With the development of aerospace technology, protective materials for hot-end components have reached higher requirements. In this paper, a （Zr x Y（1-x/4）Ta（1-x/4）Ti（1-x/4）Er（1-x/4））O（x=0.2，0.544，0.672，0.796和0.92）quintuple element ceramic system composite is studied based on the solid-phase reaction method and molecular dynamics simulation. By experimental means, ZrO2 （99.99%）, Y2O3 （99.99%）, Ta2O5 （99.99%）, Er2O3 （99.99%） and TiO2 （99%） powder was used as raw material to prepare （Zr x Y（1-x/4）Ta（1-x/4）Ti（1-x/4）Er（1-x/4））O composite by the solid-phase reaction method. The thermal conductivity of （Zr x Y（1-x/4）Ta（1-x/4）Ti（1-x/4）Er（1-x/4））O ceramic material was investigated computationally using the LAMMPS program. The study result shows that a consistent trend in the variation of the thermal conductivity is obtained by experiments and simulations at the interval of 200-900 °C. The thermal conductivity reaches a minimum value at x = 0.796, which proves the feasibility of molecular dynamics simulation of the thermal conductivity of multi-ceramic materials. Meanwhile, the effect of porosity on thermal conductivity was investigated, and it is found that there was a competitive relationship between the elemental ratios and the effect of porosity on thermal conductivity. When the porosity is larger than 6.67%, the effect of the porosity is the main influencing factor. when the porosity is smaller than 6.67%, the elemental ratios are the dominant factors in the thermal conductivity.Key words: ceramic materials；molecular dynamics；thermal conductivity；porosity在高温推进和能源发电系统中，复杂的热化学和热机械环境通常要求使用不同性能的材料组合。
金的等离子共振等综述
a b s t r a c t
This review describes the fundamental aspects of laser–gold nanoparticle (Au NP) interaction that leads to nanoscale energy deposition to the surroundings through light amplification and heat generation. Besides the importance of the primary process in physics and chemistry, application of the light–NP interaction has attracted significant interest from various areas ranging from analytical chemistry to material chemistry and biomedicine. Here we consider both mechanistic and application aspects. Our attention is focused on pulsed-laser-induced fast processes that revealed the heating–cooling dynamics of electrons, lattice (particle), and particle’s environment. On the application side, we focus on material fabrication and processing that beat diffraction-limited resolution. Together, we will shed a light on the essence of research activities carried out in the past 10 years. In addition to an abundance of latest information obtained from currently available literature, this review includes figures obtained by our own calculations to provide readers with a better understanding of the basics of the optical properties and energy and heat-transfer processes of Au NPs, which are not familiar to photochemists. © 2012 Elsevier B.V. All rights reserved.
压阻式硅MEMS谐振器的结构设计及工艺仿真
AbstractCompared with quartz resonators，MEMS resonator has advantages of high quality factor,low temperature drift,excellent phase noise performance,low power consumption, and especially the compatibility with the CMOS fabrication process which makes MEMS resonator promisingly to replace quartz resonator in the future integrated circuit systems.Piezoresistive silicon MEMS resonator is electrostatic actuated and the motion is detected by the piezoresistive effect of silicon.Different from other resonators such as electromagnetic and piezoelectric,it only needs silicon,the basic IC material,without needing other special pared with the capacitive MEMS resonator,it has low output resistance and can be highly integrated in the circuit.In this thesis,we analysed the piezoresistive silicon MEMS resonator with resonant frequency over hundreds of MHz by COMSOL Multiphysics simulation software. Frequency responses of the resonators with four geometrical structures were studied.The relationships between the critical dimension and the resonant characteristics such as resonator frequency,quality factor and output voltage were calibrated when scaled down with feature size of5μm,1μm,500nm,350nm,180nm,100nm and50nm,respectively.By optimizing the structure,a906.4MHz resonator with the quality factor of4352under the critical dimension of500nm and a1.3GHz resonator with the quality factor of2817under the critical dimension of350nm were obtained with great application potential.The fabrication process of the resonator was simulated by SILVACO TCAD focusing on the photolithographic and RIE etch process.Keywords:Piezoresistive Silicon MEMS resonator Finite Element Analysis Processing Simulation目录摘要 (I)Abstract (II)1绪论1.1MEMS谐振器 (1)1.2压阻式硅MEMS谐振器及其发展现状 (3)1.3本文的研究内容 (6)2压阻式硅MEMS谐振器的工作原理2.1压阻式硅MEMS谐振器工作原理 (7)2.2压阻式硅MEMS谐振器的机电耦合小信号模型 (11)2.3压阻式硅MEMS谐振器的关键参数 (12)2.4本章小结 (13)3压阻式硅MEMS谐振器的有限元模拟3.1多物理场耦合软件COMSOL M ULTIPHYSICS简介 (14)3.2压阻式硅MEMS谐振器模型 (14)3.3压阻式硅MEMS谐振器的谐振特性 (18)3.4压阻式硅MEMS谐振器的优化 (28)3.5考虑工艺误差的仿真 (30)3.6本章小结 (32)4压阻式硅MEMS谐振器的工艺仿真4.1二维工艺模拟器ATHENA简介 (33)4.2SOI衬底制备压阻式硅MEMS谐振器的工艺仿真 (34)4.3工艺模拟优化 (44)4.4本章小结 (51)5总结 (52)致谢 (53)参考文献 (54)华中科技大学硕士学位论文1绪论1.1MEMS谐振器1.1.1MEMS谐振器的发展现状MEMS谐振器是微机电系统中非常重要的元件，其作用是将微机械振动转换为电学信号，或者使用电信号对微结构进行激励，实现对频率信号的调制[1]。
半导体表面与MIS结构(1)
x轴的原点。鉴于表面线度远比空间电荷层厚度要
大。把表面近似看成无限大的面，故可以看成一
维情况处理。
metal
semi
isolator
x Space charge
〔1〕外表电场Es分布
取 半 导 体 体 内 电 势 V 0
Ec
Ei EF Ev
*考虑在外表层中载流 子满足经典统计； *外表空间电荷层中的 电离杂质浓度为一个 常数，和体内相等。
3、表面态的影响
表面态对半导体各中物理过程有重要影响，特别 是对许多半导体器件的性能影响更大。
§ 7·2 表 面 电 场 效 应
1、外表电场效应：
在外加电场作用下，在半导体的外表层内发生的 物理现象，主要载流子的输运性质的改变。
可以采用不同方法，使得半导体外表层内产生电 场，如：功函数不同的金属和半导体接触〔金/ 半接触〕、使半导体外表吸附某种带电的离子等
qV x
1np0e k0T
1 6
在 6式两边 d并 V 同积 乘 并 分 以 且 EdV/dx
E2 2k q 0T 2 2q r2sp 0k p0 0T
太复杂！
eqk0 T V xqk0T V x1 n pp p0 0 eqk0 T V xqk0T V x1 7
2〕外表区的少子 电子数>多子空穴 数—外表反型出现；
3〕反型层发生在 外表处，和半导体 内部之间还夹着一 层耗尽层。
二、外表空间电荷层的电场、电势和电容
为了深入地分析外表空间电荷层的性质，可以通 过解泊松方程，定量地求出外表层中电场强度E 和电势V的分布，分析电容的变化规律。
取x轴垂直于表面指向半导体内部，规定表面处为
从硅外表态的实验测量中，证实其外表能级 由两组组成： 一组为施主能级，靠近价带； 另一组为受主能级，靠近导带。
毕业论文----半导体热电材料的应用及研究进展
半导体热电材料的应用及研究进展物理与电子工程学院物理学（物理）专业 2009级袁仲富指导教师田德祥摘要：本文首先简单介绍了热电材料的三种效应以及半导体热电材料在热电发电和制冷方面的应用，然后重点介绍半导体热电材料国内外的研究进展及其方向。
关键词：半导体热电材料；塞贝克系数；电导率；热导率；热电优值Abstract:This paper first introduces the three effect of thermoelectric materials and semiconductor thermoelectric materials on thermoelectric power generation and refrigeration applications，and then focuses on the semiconductor thermoelectric materials at home and abroad research progress and its direction..Key word:Semiconductor thermoelectric materials；The seebeck coefficient；Electrical conductivity；Thermal conductivity；Thermal power optimal value1 引言从1823年，Thoums Seebeck 发现了热电效应(即塞贝克效应[1])，人们开始了解热电材料，经过一百多年的研究，人们对热点材料的研究已经取得了长足的进展。
20世纪50—60年代，由于人们在热能电能相互转化特别是制冷方面的迫切要求，人们研究了很多有价值的热电材料，其中有很多热电材料得到了广泛的应用。
70年代以来，由于氟利昂制冷技术的发展，热电材料的研究几乎处于停顿状态。
近年来，氟利昂对环境尤其是对臭氧层的破坏被人们所认识，制造无污染，无噪声的制冷机成为了制冷技术的目标。
位错与残余应力
50μm 15 mm
15 mm
- 三点基本共识
- 热应力 – 位错与残余应力的共同来源 -
-
- 简化冷却会有什么后果 ？
报 告 位错形成 与 应力残余 – 平衡互补 提 多晶硅锭位错主要在什么时候形成 ？结晶时？冷却时？ 纲
- 高效多晶硅片 碎片率似相对高，原因 ？
On completion of solidification, the temperatures of the top and the bottom differ greatly. Development of thermal stress is inevitable in cooling, as the change of temperature can not keep synchronized. ~1410 C
报 告 提 纲
共识1：位错运动增殖总是伴随屈服变形和 应力释放
反过来说位错运动增殖是晶体屈服变形、释 放应力的微观机制.
共识2：启动位错增殖所需最小应力（屈服应力） 随温度提高急剧下降
120
100
Critical shear stress (MPa)
Brittle / Plastic transit： ～750 C
横向晶界并不可怕，纵向切硅片做电池并没 有更差。
位错是问题，晶界不是问题
铸造多晶硅片位错密度和有效少子寿命分布图
- 三点基本共识 - 热应力 – 位错与残余应力的共同来源 - 位错形成 与 应力残余 – 平衡互补
- 结晶生长：持续柱状生长带来的问题
- 冷却：简化的好处和风险 - 高效多晶硅片 碎片率似相对高，原因 ？
Dislocation Multiplication Rate (k0/m s)
矿化度对疏水缔合聚合物聚集行为的影响
矿化度对疏水缔合聚合物聚集行为的影响施雷庭;朱诗杰;叶仲斌;赵旭斌;彭洋平;宋明珊【摘要】To take the laboratory made synthetic branched polymer DHAP and far-chelate hydrophobic associating polymer HMPAM as the research objects to study the effect of salinity on the aggregation behavior.The microstructure of the polymer aggregation behavior of hydrophobic associating polymer HMPAM and DHAP with concentration which were 1 000 mg/L and 2 000 mg/L in brine was observed by atomic force microscope.And the effect of salinity on the hydrodynamic volume of aggregation was further studied by dynamic light scattering method.The result indicated that the aggregation of DHAP in brine would form a large size cluster and the aggregation of HMPAM in brine would form a large size tendon.With the increase of salinity,the size of the aggregations in the brine of two kinds of hydrophobic associating polymers appeared to increase first and then decrease.But the clustershape hydrophobic associating polymer had better salt resistance.The larger space volume of the polymer was in the same salinity conditions,the less effected by salinity,the stronger viscosifying capacity.%以实验室自制合成的支型和远鳌型疏水缔合聚合物DHAP和HMPAM为对象,研究了矿化度对聚集行为的影响.通过原子力显微镜观察了质量浓度为1 000 mg/L和2 000 mg/L的疏水缔合聚合物DHAP和HMPAM在盐水条件下的聚合物聚集行为的微观形貌,并通过动态光散射方法进一步研究了矿化度对聚集体水动力学尺寸的影响.结果表明:DHAP聚集体在盐溶液中会形成尺寸较大的“团簇”状形态,HMPAM聚集体在盐溶液中会形成尺寸较大的“链束”状形态,随着矿化度的增加,两种疏水缔合聚合物在水溶液中的聚集体尺寸都出现了先增大再减小的趋势,但是“团簇”状的枝化疏水缔合聚合物具有更好的抗盐能力.空间体积越大的聚合物在相同矿化度条件下,受影响较小,具有更强的增黏性能.【期刊名称】《精细石油化工》【年(卷),期】2017(034)005【总页数】6页(P9-14)【关键词】疏水缔合聚合物;矿化度;聚集行为【作者】施雷庭;朱诗杰;叶仲斌;赵旭斌;彭洋平;宋明珊【作者单位】油气藏地质与开发工程国家重点实验室,西南石油大学,四川成都610500;西南石油大学石油与天然气工程学院,四川成都610500;油气藏地质与开发工程国家重点实验室,西南石油大学,四川成都610500;西南石油大学石油与天然气工程学院,四川成都610500;油气藏地质与开发工程国家重点实验室,西南石油大学,四川成都610500;新疆油田分公司百口泉采油厂油田工艺研究所,新疆克拉玛依834000;新疆油田分公司百口泉采油厂油田工艺研究所,新疆克拉玛依834000;中国石油化工有限公司西南油气分公司工程技术研究院,四川成都610000【正文语种】中文【中图分类】TE357.46目前，普通稠油油藏聚合物驱成为提高采收率的主要方式，但聚合物溶液因受到油藏高矿化度等因素的影响，聚合物溶液增黏性变差，同时残余阻力系数也在下降，严重制约着聚合物驱在高矿化度油藏中的应用[1-3]。