(1. 中国民航大学 理学院低维材料与技术研究所，天津 300300；
2. 中国民航大学 中欧航空工程师学院，天津 300300)
摘 要: 采用基于密度泛函理论计算研究了钼(或铬，钒)原子替位掺杂双相γ-TiAl/α2-Ti3Al界面体系的平均形成能、断裂功、电子结构等。结果显示：各个掺杂体系的总能量和平均形成能均为负值，表明它们可以由实验制备并能稳定存在。对代表性体系的断裂功和态密度分析表明，体系Mo-Sa5 (或Cr-Sa5)的结合强度减弱，同时体系Mo-Sa5的Mo-d和Ti-d电子态密度增加、相互作用增强，而Ti-d和Al-p轨道杂化键强度降低，位错运动的阻力减少，有利于改善TiAl合金材料的延性。对杂质原子所在(001)面电荷密度和布居数的分析发现，Mo(或V)的掺入会引起电子云在杂质原子周围的聚集效应，形成结合强度稍高的区域，该区域与周围其他区域结合的各向异性程度下降。这正是此类TiAl合金延性改善的内因。
关键字: 双相γ-TiAl/α2-Ti3Al界面；能量性质；延性；电子性质；第一性原理
（1. Institute of Low Dimensional Materials and Technology, College of Science, Civil Aviation University of China, Tianjin 300300, China;
2. Sino-European Institute of Aviation Engineering, Civil Aviation University of China, Tianjin 300300, China）
Abstract:The average formation energies, Griffith fracture works and electronic structures of Mo (or Cr, V) doping of γ-TiAl/α2-Ti3Al interfacial systems were calculated with density functional theory. The results indicate that these systems possess energy stability and can be prepared by experiments and exist stably. The Griffith fracture work and density of the representative system show that the bonding strength of Mo-Sa5 (or Cr-Sa5) is weakened and the densities of state of Mo-d and Ti-d electrons of Mo-Sa5 are increased. The charge density map of the (001) plane passing through impurity atom and populations of the doping system show that, there is an electron cloud aggregation effect surrounding the dopant caused by the doping of Mo (or V) atom, which forms a region with a slightly higher bonding strength. As a result, the anisotropy degree of the combination of this region is reduced, which is the internal reason of the improved ductility for TiAl alloys.
Key words: dual-phase γ-TiAl/α2-Ti3Al interface; energy property; ductility; electronic property; first-principle
