Improvement in the oxidation resistance of α2-Ti3Al by sputtering Al film and subsequent interdiffusion treatment

Sputtering Al film on α2-Ti3Al alloy and subsequent interdiffusion treatment at 600 °C for 24 h in high vacuum can effectively improve its oxidation resistance, due to a good adhesive TiAl3 layer formed on the surface. The thicker the Al film, the thicker the TiAl3 layer that can be formed. Cyclic and isothermal oxidation tests at 800 °C in air show that the α2-Ti3Al with 3–5 μm Al film can dramatically reduce its oxidation rate, and the parabolic oxidation rate constant Kp of specimen with 5 μm Al film is only approximately 1/5000 of that of bare α2-Ti3Al. The X-ray diffractometer and scanning electron microscopic results indicate that the TiAl3 layer has formed a protective and continuous α-Al2O3 scale on the outer surface, and inter-reacted with α2-Ti3Al to form γ-TiAl phase at 800 °C after 80 h of oxidation, i.e. there are layers of α-Al2O3/γ-TiAl/α2-Ti3Al formed on specimens.