学术报告
应PP电子游戏网站丁学勇教授邀请，奥地利维也纳大学物理化学研究所Peter Rogl教授、Gerda Rogl博士将于2018年4月26日-5月3日访问我校，并做学术报告。欢迎冶金、材料学院及其他学院的老师和同学们踊跃参加。
1、报告人Peter Rogl教授，内容：High ZT Spinodal Half-Heusler Alloys for Efficient Thermoelectric Energy Conversion
时间：4月26日（星期四） 下午3:00—4:30
地点：冶金学馆311B会议室
2、报告人Gerda Rogl博士，内容：Development of high ZT skutterudites for thermoelectric applications
时间：5月3日（星期四） 下午3:00—4:30
地点：冶金学馆311B会议室
报告人简介
P. Rogl教授和G. Rogl博士在超导、金属间化合物和热电材料等领域做了大量研究，取得了多项成果。P. Rogl是享誉世界的著名教授，现任奥地利维也纳大学物理化学研究所教授以及PP电子游戏网站荣誉教授，发表过650多篇学术论文和24本专著，担任多种重要期刊的评审人和编辑委员会成员，获得过各种奖励和荣誉称号。
内容简介：
P.Rogl教授的报告: Multi-component half-Heusler phases (noncentrosymmetric MgAgAs-type) have proven to be excellent thermoelectrics. The Large-scale production and particularly nanostructuring of (Ti,Zr)NiSn-based thermoelectric materials by preferably system-inherent phases need a profound knowledge not only of isothermal phase relations, temperature dependent solubilities but also of the solidification behavior.
The presentation covers a detailed experimental investigation of the constitution of the systems Ti-Ni-Sn and Zr-Ni-Sn including liquidus projections and Scheil diagrams, as well as CALPHAD calculations of the entire ternaries. For the quasi-binary systems TiNiSn - ZrNiSn and TiNiSn - HfNiSn, thermodynamic spinodal/binodal curves have been determined from solubility data and DFT calculations. With the measured relevant elastic moduli also the corresponding depression of the critical points of coherent spinodal demixing have been derived.
From a series of compounds Ti1-x-yZrxHfyNiSn and respective Sn/Sb substituted compounds the thermoelectric behavior was characterized and found to reach ZT=1.6 at 870 K but for Hf-free, n-type Ti0.5Zr0.5NiSn0.98Sb0.02 a ZT ~ 1.2 at 870 K yielding an thermoelectric efficiency h ~ 11%. For the p-type counterparts alloys Nb1-xMxFe(Sb,Sn) (M=Ti or Y, Zr) reaching ZT=1.2 at 870 K are used. These excellent TE data on spinodally demixed alloys prove that Hf-free and therefore cheap half-Heusler alloys can be promising materials for a large scale production route. The experimental data (backed by SEM/TEM analyses) are compared with DFT results and discussed.
G.Rogl博士的报告: Filled skutterudites are among the best candidates for thermoelectric (TE) applications, particularly in automotives, because they cover the temperature range needed for TE devices, the starting material is cheap and abundant and they can be produced easily and fast. The highest ZT values for both p- and n-type skutterudites have been renewed continuously, recently reaching ZT = 1.3 for double or multifilled p-type and ZT = 1.8 for multi filled n-type skutterudites. The development of the design and preparation of high ZT p-and n-type skutterudites and their stability will be discussed and it will be shown how these high values could be increased after severe plastic deformation (SPD) via high pressure torsion (HPT) to ZT > 1.4 and ZT > 1.9, respectively.
Thermal expansions of the material as well as mechanical properties play an important role; their values should be as similar as possible for p- and n-type alloys to avoid stresses when used in a TE device under cyclic temperature gradients. Therefore an overview will be presented on mechanical property data available in the literature including all results of our investigations.
