Zr替位掺杂γ-TiAl的稳定性和热学性质研究

An investigation on the stability and thermal property of γ-TiAl doped with Zr-substitution

采用基于密度泛函理论的第一性原理方法,计算了γ-TiAl和过渡金属Zr替位掺杂γ-TiAl形成的Ti8Al7Zr和Ti7ZrAl8体系的几何结构、总能量、结合能、声子谱和热学参量。通过对几何结构和结合能的计算分析揭示Zr替位掺杂γ-TiAl能够改善材料的稳定性和延性。能带结构和态密度表明Ti8Al7Zr和Ti7ZrAl8体系具有金属导电性。计算的声子谱显示Ti7ZrAl8体系具有很好的稳定性。计算结果显示Ti8Al7Zr和Ti7ZrAl8体系均具有较大而且稳定的高温热容量和热导率,比γ-TiAl有显著的改善。Ti8Al7Zr和Ti7ZrAl8体系的较大的热容量和热导率都有利于γ-TiAl基合金的技术应用。

Computation studies about the geometry structures,total energies,binding energies,photon disper-sions and thermal parameters of pure and Zr-substitution doping γ-TiAl were fulfilled by the first-principles method based on the density function theory.The calculated results about geometry structures and binding ener-gies show that Zr-substitution doping can improve the stability and the ductibility of γ-TiAl based alloys.The band structures and densities of states indicate the metal conductivity of Ti8 Al7 Zr and Ti7 ZrAl8 systems.The obtained photon dispersion implies good stability of Ti7 ZrAl8 system.According to the calculated results, Ti8 Al7 Zr and Ti7 ZrAl8 systems possess big and stable thermal capacity and conductivity at high temperatures far better than those ofγ-TiAl.The big thermal capacity and conductivity of Ti8 Al7 Zr and Ti7 ZrAl8 systems are propitious to the application of the γ-TiAl based alloys.