12月4日（周二）名师讲坛：相固溶体合成、微观结构表征及物理性能
【主 题】：相固溶体的合成、微观结构表征及物理性能
【主讲人】：Sylvain Dubois 教授，法国普瓦捷大学副校长
【时 间】：2012年12月4日（星期二）下午14：30-16：30
【地 点】：机电学院大会议室（机械工程楼Z802B）
【主 办】：研究生工作部
【承 办】：机电学院
【主讲人简介】：
Professor Sylvain Dubois is the Chief of the departement of Chemistry of the Poitiers Institute of Technology. In 2012, he was appointed to vice-president of the Poitiers University, in charge of research.
He has published 70+ articles in scientific ISI journals, hindex="18" and 118 communications in congress among which 57 oral communications as speaker. He contributed 2 chapters in books, was an organizer of 3 symposiums on MAX phases (Pittsburgh, Daytona Beach and Houston (USA)), is a referee for different journals: Journal of Applied Physics, Journal of the American Ceramic Society, Journal of Alloys and Compounds, Physical Review B, etc. His main research activities are: synthesis and properties of nano-materials; MAX phases-nanolaminated materials and related properties; relationship between micro or nano-structure and physical properties; studied materials: Magnetic nanowires, superconducting nanowires, multilayered nanowires-Relation between the reduced dimension of the object under study and the scaling length of the physical property – such a project led him to work during 4 years with Pr. A. Fert (Nobel Prize in physics in 2007).
【讲座简介】：
Ti2AlC, Ti2AlN and sub-stoichiometric Ti2Al(C(1-x)Nx)y (y<1) MAX phase solid solutions have been successfully synthesized by using a Hot Isostatic Press (HIP). Microstructures of the HIPed samples are observed by Scanning Electron Microscopy. Wavelength Dispersive X-ray Spectroscopy analyses are performed to determine the C and N contents of the solid solutions. Nanoindentation has been used to measure the intrinsic hardness and the Young’s modulus of the different Ti2Al(C(1-x)Nx)y solid solutions. Four point probe resistivity measurements were performed as a function of temperature on Ti2AlN, Ti2AlC0.25N0.75, Ti2AlC0.4N0.4, Ti2AlC0.5N0.5, Ti2AlC0.75N0.25 and Ti2AlC samples. In a last step, the anisotropy of Ti2AlC transport properties is understood from the compared study of both a highly-oriented (000l) Ti2AlC thin film and a Ti2AlC polycrystalline bulk sample.
利用热压烧结已成功合成了Ti2AlC, Ti2AlN 以及亚化学计量的Ti2Al(C(1-x)Nx)y (y<1) MAX相固溶体。然后分别采用扫描电子显微镜和Ｘ射线波谱分析，观察各固溶体显微结构和确定了各固溶体中Ｃ和Ｎ的含量。采用纳米压痕法测定了不同Ti2Al(C(1-x)Nx)y固溶体的本征硬度和杨氏模量。使用四点探针法确定了Ti2AlN, Ti2AlC0.25N0.75, Ti2AlC0.4N0.4, Ti2AlC0.5N0.5, Ti2AlC0.75N0.25和Ti2AlC等的电阻率与温度的关系。最后，通过对比研究(000l)方向上高取向度的Ti2AlC薄膜和Ti2AlC多晶块体，Ti2AlC传导性能的各向异性得到很好的理解。