Competitive Effect of Nb and V on High-Temperature Oxidation of α₂-Ti-30Al Alloys

The competitive effect of Nb and V additions on the high-temperature oxidation behavior of Ti- 30Al alloys were studied at 800°C in air. Oxidation performance increased with increasing Nb content, however, V additions eliminated the beneficial effect of Nb on oxidation performance, causing higher oxidation mass gains. In-situ high-temperature XRD by means of synchrotron source suggested dissolution of Nb⁵⁺ but lower valence of vanadium ions in the TiO₂ oxide scale during oxidation. Dissolution of Nb and V ions with different valence in TiO₂ during oxidation could cause the beneficial and detrimental effects observed on the performance of high-temperature oxidation of Ti-30Al.