The influence of conditions of compatibility on microstructure at phase transformation

报告题目：The influence of conditions of compatibility on microstructure at phase transformation

报告人：陈弦博士，美国劳伦斯伯克利国家实验室
时间： 02月02日上午09:30-10:30 
地点： 力学一楼四楼会议室 (427)
举办单位：材料力学行为与设计中科院重点实验室

Dr. Xian Chen
Advanced Light Source, Lawrence Berkeley National Lab
University of Minnesota, Aerospace Engineering and Mechanics

摘要：

Materials undergoing reversible phase transformationhave tremendous potential for applications such as electrochemical energystorage media [1], medical devices, microelectronic sensors, robotic actuators,solidstate refrigerators [2] and energy conversion devices [3]. Theseapplications rely on the changes of crystal structure during phasetransformation. This structural change, together with the lattice parametersensitivity of magnetoelectric properties, also underlies an approach to thediscovery of multiferroic alloys with great potential for new technology.However, the inevitable formation of microstructure during phase transformationintroduces stressed transition layers due to the lattice misfit. This, in turn,drives the nucleation of defects that leads to the degradation of the materialunder cyclic transformation. This problem is the single most important obstaclepreventing the widespread use of phase transformations in many areas such asmicroelectronics, battery industries and aerospace engineering. My work hasrevealed that conditions of compatibility have an important impact on therelationship between microstructure and material properties [4, 5, 6, 7]. Asillustrated in Figure 1, when the lattice parameters of materials are made tosatisfy certain conditions of compatibility [7, 6, 4], the thermal hysteresisis minimized, the reversibility is enhanced and the material exhibits unusualfluid-like flexible martensite microstructure [5]. Building on my past work, Ihave proposed a combined theoretical, algorithmic and experimental approach to thestudy and discovery of phase-transforming materials with enhanced properties.

个人简介：陈弦博士于2013 年毕业于美国明尼苏达大学双城分校，美国Lawrence Berkeley 国家实验室ALS fellowship博士后。主要研究领域为晶体力学和新材料开发，已发表多篇高水平论文其中包括一篇Nature（equally contributed），一篇JMPS, 一篇Acta Mater. 和一篇APL等。她将前人在可逆型固态相变相容性理论往前推进了一大步，提出余因子条件，并将相容性的概念推广到非可逆型扩散相变中，第一个提出弱相容性的概念，并且成功的应用到热电材料的self-assembly 合成中，并精准的预测了材料析出相的取向性。

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