Investigation on effects of alloying on oxidation resistance of γ-TiAl by using first principle

Abstract

The oxidation energies of Al2O3 and TiO2 containing different transition metal alloying elements were calculated by using a first-principles plane-wave pseudoptential method, the effect of alloying on the relative stabilities of Al2O3 and TiO2 was also analyzed. The results showed that almost all the alloying elements increased the oxidation energies of Al2O3 and TiO2, i.e., destabilized both Al2O3 and TiO2. Comparing the oxidation energies of Al2O3 and TiO2, it was foud that, W, Mo, Re, Nb, etc., decreased significantly the stabilities of Al2O3 relative to that of TiO2, indicating that these alloying elements may hamper efficiently the inner oxidation of Al in the γ-TiAl matrix so as to increase the high-temperature oxidation resistance of γ-TiAl. © Copyright.