Evolution of surface oxide layers during isothermal oxidation of a multi-component oxide dispersion strengthened Fe₃Al alloy

This study is concerned with the mechanism and kinetics of isothermal oxidation of a newly developed oxide dispersion strengthened Fe₃Al with Cr and Ti additions (Fe–12.7Al–5.8Cr–0.25Ti–0.35Y₂O₃) at 900 and 1050 °C for a duration of 2000 h under ambient atmosphere. The oxidation rate is similar at both the temperatures up to 1200 h, beyond which, the rate is higher for the samples oxidized at 1050 °C. The spallation of oxidation products is higher at 900 °C. The rate constants for the reaction and instantaneous rate constants confirm the formation of various types of oxides and other associated processes as a function of time and temperature. The alloy under study has been proven to exhibit superior resistance to oxidation at high temperatures, when compared to other commercially available ODS–Fe₃Al alloys and superalloys developed for similar applications. The superior oxidation of this material is due to the formation of stable α-Al₂O₃ layer along with layers of Fe₂O₃, Cr₂O₃ and assimilation of metastable TiO.