First-Principles Studies of γ-Tial Based Ternary Alloys

摘要: Self-consistent total energy calculations were performed to investigate the effects of ternary additions 3d, 4d and 5d transition metal elements L1{sub 0} ordered {gamma}-TiAl. In general, authors studied solids 4 atoms per unit cell. case Mn larger supercells with up 32 also treated. Minimizing respect volume c/a ratio leads determination lattice distortions due alloying by elements. These prove be strongly dependent on whether element substitutes Al or Ti atoms. Furthermore, site preference can derived comparing formation energies Ti{sub n{minus}1}XAl{sub n} n}XAl{sub n{minus}1}, where X is substituting element. As a result change geometry TiAl estimated may thereby give insight into conditions at semicoherent {gamma}/{gamma}{prime} {alpha}{sub 2}/{gamma} interfaces, which are associated responsible for ductility improvements {gamma}-TiAl based alloys.