High temperature oxidation of Ti–46Al–6Nb–0.5W–0.5Cr–0.3Si–0.1C alloy

• Ti–46Al–6Nb–0.5W–0.5Cr–0.3Si–0.1C (at%) alloy was newly developed.
• The high-temperature oxidation behavior of the new TiAl-base alloy was described.
• The good isothermal and cyclic oxidation resistance was discussed.

A newly developed Ti–46Al–6Nb-0.5W-0.5Cr-0.3Si-0.1C alloy was oxidized isothermally and cyclically in air, and its high-temperature oxidation behavior was investigated. When the alloy was isothermally oxidized at 700 °C for 2000 h, the weight gain was only 0.15 mg/cm2. The parabolic rate constant, kp (mg2/cm4·h), measured from isothermal oxidation tests was 0.002 at 900 °C and 0.009 at 1000 °C. Such excellent isothermal oxidation resistance resulted from the formation of the dense, continuous Al2O3 layer between the outer TiO2 layer and the inner (TiO2-rich, Al2O3-deficient) layer. The alloy also displayed good cyclic oxidation resistance at 900 °C. Some noticeable scale spallation began to occur after 68 h at 1000 °C during the cyclic oxidation test.