Abstract
The high-temperature oxidation behavior of Ti– (6–36) mass%Al alloys and Ti– (4–15) mass%V alloys have been investigated in a temperature range of 1123 to 1273 K in air. A kinetic study of the oxidation has been also carried out in Ti–6 mass%Al alloy and Ti–4 mass%V alloy. The growth rate of oxides in Ti–V alloys is larger than that in Ti–Al alloys. The oxidation products have been examined by X-ray diffraction (XRD), electron probe microanalysis (EPMA) and X-ray photoelectron spectroscopy (XPS). The Al2O3 layer is probably formed in the Ti–Al/oxides interface of the Ti–6 mass%Al alloy by means of EPMA, although only the rutile TiO2 is detected by means of XRD in the oxides of surface layer in Ti–6 mass% Al alloy and Ti–4 mass%V alloy at 1273 K. Furthermore, the TiO2 and Al2O3 are observed by XPS in surface of the above both alloys at 1123 K for 3.6 ks, but the V2O5 is not observed. It is found that the apparent activation energy (245 kJ/mol) for the oxidation experiment (TG experiment) at a constant heating rate is fairly equal to the activation energy (253 kJ/mol) for the isothermal oxidation in Ti–6 mass%Al alloys.
