High temperature oxidation of AlCrFe complex metallic alloys

•Oxidation of Al65Cr27Fe8 and Al80Cr15Fe5 was studied in the 600–1080°C temperature range.•Formation of transient alumina scales is obtained up to 900°C.•α-Alumina is formed on Al65Cr27Fe8 at temperatures higher than 1000°C.•Very good oxidation resistance is observed for of Al65Cr27Fe8 up to 1080°C.•Scale spallation and thermal etching of the alloy surface is observed on Al80Cr15Fe5. Isothermal oxidation of Al65Cr27Fe8 and Al80Cr15Fe5 was studied in the 600–1080°C range. Formation of transient alumina layers is obtained up to 900°C. On Al65Cr27Fe8 transient to α-phase transformations occur when performing oxidation at 1000°C, together with the possible appearance of (Al0.9Cr0.1)2O3. At 1080°C, direct formation of α-alumina is obtained. On Al80Cr15Fe5, spallation of the oxide layer during the cooling stage is observed following oxidation at 800 and 900°C, revealing thermal etching of the underneath alloy surface. At 1050°C the α-Al2O3 scale is directly formed but plastic deformation and recrystallization of the underneath alloy into several intermetallic phases is observed.