3d过渡元素掺杂对TiAl合金力学性能及电子性质的理论研究

Effect of 3d transition element doping on mechanical properties and electronic properties of TiAl alloy

采用基于密度泛函理论的第一性原理方法,计算研究Cr、Mn、Fe和Co元素掺杂TiAl体系的择优占位取向、晶体结构、延性和电子性质。结果发现:金属元素掺杂可以改善材料的立方度,从而提升材料的塑性,浓度对Co元素影响不大,轴比稳定在1以上;掺杂后体系B G增大,且随浓度的增加而增大,材料的延性有很大提升,Co元素对于增强TiAl延性效果显著。分析Co元素掺杂体系的电子性质发现,掺杂元素利于抑制Ti-Al键相互作用,从而降低金属脆性,提升延展性,掺杂浓度升高,延展性进一步提升。

The occupation, crystal structure, ductility and electronic structure of TiAl alloy doped with Cr, Mn, Fe and Co elements were calculated by using first-principles based on density functional theory. The results show that the materials doped with metal element can improve the cubic degree, so as to improve the ductility, and the concentration has little influence on the Co element, the axial ratio is more than 1. As the value of B/G increases, the ductility of the materials is improved, and the effect of Co element is more obvious than other elements. The electronic structure was analyzed to investigate the mechanism of doping Co element. The results show that doping Co element is beneficial to inhibiting the interaction of Ti-Al bonds, so as to enhance the ductility of materials, and the doping concentration has a certain impact, the higher the concentration, the higher the ductility.