Effect of Mo-alloyed layer on oxidation behavior of TiAl-based alloy

A Mo-alloyed layer was prepared on a TiAl-based alloy using plasma surface metallurgy technique. The microstructure and oxidation behavior of the alloyed TiAl were investigated. The surface alloyed layer with a thickness of approx. 40 μm and a gradient concentration distribution was composed of Ti2MoAl, TiAl and Mo phases. Cycling oxidation test was carried out at 850 °C in air under an atmospheric pressure. The result of the oxidation kinetics test shows that the mass gain of the Mo-alloyed TiAl after exposure for 100 h was less than the value of the untreated TiAl substrate, exhibiting an improved oxidation resistance. The Al2O3-rich mixed oxide scale formed on the alloyed TiAl is supposed to be the main reason of the beneficial effect on the improvement of oxidation resistance for TiAl-based alloy.