Oxidation of a ternary Ti3Al-Ta alloy

Abstract

The isothermal oxidation behavior of a ternary Ti-25Al-18Ta intermetallic alloy has been investigated in pure oxygen over the temperature range of 850°C to 1100°C. The oxidation kinetics was found to follow a parabolic rate. Effective activation energy of 259 kJ/mol was deduced from the oxidation data. The oxidation products were a mixture of TiO2, the main component, Al2O3 (alumina), and small amounts of tantalum oxide. The addition of Ta to Ti3Al alloy decreased the oxidation rate of the alloy. However, the oxidation scale was not compact and exhibited significant spallation especially at high temperatures.