时间：2014年9月30日9:00

地点：能源楼会议中心一号会议室

报告人：于文波

报告人简介：

于文波，2014年6月博士毕业于法国普瓦捷大学，材料物理专业。博士期间主要开展新型耐高温耐腐蚀的金属陶瓷纳米材料MAX相化合物的研究工作。申请我所19T2组博士后岗位，合作导师：杨明辉研究员。

报告摘要：

The work discussed in this thesisconcerns the synthesis, the microstructural characterization and the physical properties of nanolaminated MAX phase’s solid solution. The Mn+1AXn phases (M: transition metal, A: IIIA or IVA group element, and X: either carbon or nitrogen) are a class of ternary nitrides and carbides (n=1 to 3), which possess some of the best properties of metal and some of the best properties of ceramics.

In a first step, we focus on the synthesis of highly pure and denseTi2AlCxNysolid solutionsby hot isostatic pressing. The influence of the substitution of C atoms by N atoms and the influence of vacancy content on thesolid solution lattice parameters is discussed.Nanoindentation tests demonstrated that solid solution effect leads to a hardening effect whereas the presence vacancy leads to a softening effect. The electrical resistivity is shown to increase with vacancy content and substitution rate. Such an effect is discussed in terms of disorder and relaxation time variation.

Finally, the anisotropic transport properties of MAX phases is studied and discussed. The anisotropy of transport properties has been evidenced by direct measurement of the resistivity along the basal plane and along the c-axis. It is demonstrated that transport property in the basal plane can be understood in the framework of a single band model with hole-like states as charge carrier.