Effect of Sn addition on the high-temperature oxidation behavior of high Nb-containing TiAl alloys

The effect of Sn addition on the oxidation behavior of high-Nb containing TiAl alloys was investigated with isothermal oxidation tests conducted in static air at 1000 °C. Sn addition can improve the high-temperature oxidation resistance of TiAl alloys by forming a protective Ti3Sn layer to diminish the inward oxygen diffusion. Moreover, the generated Al2O3 oxide pegs provide a mechanical locking to enhance the spallation resistance. The alloy containing 3 at.% Sn exhibits superior oxidation resistance, with no spallation occurring. The lowest mass gain after being oxidized for 100 h was 3.29 mg/cm2, which is 42.1 % lower than the Sn-free alloy.