Effect of lamellar microstructure on oxidation kinetics of Fe3Al sintered by hot isostatic pressing

The present paper focuses on the investigation of the relationship between microstructure of Fe3Al prepared by hot isostatic pressing (HIP) and kinetics of alumina layer formation during oxidation at 900 °C, 1000 °C and 1100 °C. As prepared HIPed Fe3Al sample reveals lamellar microstructure with inhomogeneous Al distribution which originates from the preliminary mechanical activation of Fe–Al mixture. At 900 °C, Fe3Al oxidation is characterized by selective growth of very rough alumina layer containing only transient aluminium oxides. In addition to these transient oxides, α-Al2O3 stable phase is formed at 1000 °C. At the highest temperature (1100 °C), continuous and relatively smooth alumina layer mainly contains fine crystallites of α-Al2O3. The initial lamellar structure and phase inhomogeneity in as-HIPed Fe3Al samples are supposed to be the main factors that determine observed peculiarities after Fe3Al oxidation at 900 °C and 1000 °C.