First-Principles Calculation for the Influence of C and O on the Mechanical Properties of γ-TiAl Alloy at High Temperature

The elastic constants of temperature dependence, thermal expansion coefficient and phonon dispersion relations of gamma-TiAl doped with C/O have been investigated using first-principles calculations in order to gain insight into the mechanical performance of gamma-TiAl in cases of high temperature. This study shows that gamma-TiAl maintains stability at high temperatures introduced by C or O atoms. Importantly, the hardness increases and retains excellent resistance to external pressure. The results indicate that even if the TiAl alloy is doped with C or O atoms, it can also exhibit excellent mechanical properties at a high temperature.