(1. 中國民航大學(xué) 理學(xué)院低維材料與技術(shù)研究所，天津 300300；
2. 中國民航大學(xué) 中歐航空工程師學(xué)院，天津 300300)
摘 要: 采用基于密度泛函理論計算研究了鉬(或鉻，釩)原子替位摻雜雙相γ-TiAl/α2-Ti3Al界面體系的平均形成能、斷裂功、電子結(jié)構(gòu)等。結(jié)果顯示：各個摻雜體系的總能量和平均形成能均為負值，表明它們可以由實驗制備并能穩(wěn)定存在。對代表性體系的斷裂功和態(tài)密度分析表明，體系Mo-Sa5 (或Cr-Sa5)的結(jié)合強度減弱，同時體系Mo-Sa5的Mo-d和Ti-d電子態(tài)密度增加、相互作用增強，而Ti-d和Al-p軌道雜化鍵強度降低，位錯運動的阻力減少，有利于改善TiAl合金材料的延性。對雜質(zhì)原子所在(001)面電荷密度和布居數(shù)的分析發(fā)現(xiàn)，Mo(或V)的摻入會引起電子云在雜質(zhì)原子周圍的聚集效應(yīng)，形成結(jié)合強度稍高的區(qū)域，該區(qū)域與周圍其他區(qū)域結(jié)合的各向異性程度下降。這正是此類TiAl合金延性改善的內(nèi)因。
關(guān)鍵字: 雙相γ-TiAl/α2-Ti3Al界面；能量性質(zhì)；延性；電子性質(zhì)；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
