Oxidation behavior of near α-titanium alloy Ti60

Air oxidation behavior of Ti60 alloy was studied in the temperature range from 600°C to 750°C. In addition to the determination of the oxidation kinetics by mass gain measurements, the morphology of the scales formed was observed by SEM and the phases present in the scales were characterized by X-ray diffraction. Results show that under the condition of oxidation at 600-750°C for 0-100 h, the oxidation exponent n is between 1 and 2 calculated by oxidation experience formula of Wagner, the total oxidation energy is 256 kJ/mol, and the oxidation kinetics follows the linear-parabolic law. When Ti60 alloy was oxidized at 600°C for 100 h or at 750°C for 10 h, the oxidation product is TiO₂, while there was a little Al₂O₃ on the surface when the alloy was oxidized at 750°C for 100 h. The oxides were preferentially formed at the grain boundaries of the alloy. Besides the oxidation layer on the sample surface, oxygen also dissolves into the matrix to form brittle oxygen-enriched layer resulting in the mechanical property change. The oxygen-enriched layer was thickened with the increase of oxidation temperature and prolonging of the oxidation time.