Air oxidation behaviour of Ti6Al4V alloy between 650 and 850°

Abstract The air oxidation behaviour of Ti6Al4V alloy was studied in the temperature range 650–850°C. Continuous oxidation kinetics showed that the alloy oxidised according to a parabolic rate law at 650 and 700°C after a transient period, whilst at 750 and 800°C, linear-parabolic kinetics dominated. At 850°C, after 50 h linear-parabolic oxidation, the alloy followed a parabolic rate law. The multilayered oxide scales formed on the oxidised alloy consisted of alternate layers of Al2O3 and TiO2. The number of Al2O3 and TiO2 layers increased with increasing exposure time and temperature. The external gas/oxide interface was always occupied by an Al2O3 layer whilst TiO2 always appeared at the oxide/substrate interface.