5d过渡金属掺杂γ-TiAl合金的第一性原理研究

摘要

采用基于密度泛函理论的第一性原理平面波赝势方法,系统地研究了5d过渡金属在γ-TiAl合金中的占位及占位方式,获得了过渡金属掺杂合金体系的形成能、几何结构、电子结构及电荷布居值等参数.结果表明:5d过渡金属元素Hf、Ta和W优先占据γ-TiAl合金中的Ti位；Os、Ir、Pt、Au等优先占据Al位；Re则既有占据Ti位的可能,也有占据Al位的可能,但占据Al位的趋势略大.通过对不同元素掺杂体系的能带结构、态密度和电荷布居值的计算和分析,进一步验证了不同过渡金属元素在TiAl合金中的占位规律,解释了5d过渡金属掺杂对TiAl合金体系结构和性能的影响.%Site substitutions of 5d transition metal elements in γ-TiAl alloy were investigated by first-principle plane-wave pseudopotential method based on density functional theory (DFT). The formation energy, geometric and electronic slructure. and Mullikcn population were obtained. The results show that Hf, Ta and W mainly substitute for Ti in y-TiAl alloy, and Os. Ir. Pt and Au preferentially substitute for Al in γ-TiAl alloy. Re has two substitution possibilities in γ-TiAl alloy-Ti and Al site, but the preference for substitution at Al site is a little stronger. Through the calculation and analysis for band structure, density of state, and Mulliken population in systems substituted by various elements, the site substitution disciplinarians were confirmed, and the effects on structure and performance of TiAl alloy were explained.