Isothermal oxidation behavior of powder metallurgy beta gamma TiAl-2Nb-2Mo alloy

► PM beta gamma TiAl-2Nb-2Mo alloy forms Ti and Al oxides at 800 °C and 900 °C. ► TiN phase forms at the oxide/substrate interface owing to the nitrogen effect. ► Diffusion zone formed by degradation of lamellar colonies containing beta phases. ► Weight gain curve obeys the parabolic law at 800 °C and 900 °C up to 500 h.