Unraveling the origin of the excellent high-temperature oxidation resistance of an AlCrFeNiTi complex concentrated alloy

Oxidation behavior of Al8Cr13.3Fe63.5Ni11.2Ti4 complex concentrated alloy was studied in the air at 800 degrees C. Results show that the oxidation kinetics does not obey a parabola relationship. The oxidation process was divided into two distinct stages, transforming from an approximately parabolic law to a quasi-linear law at 10 h. This alloy exhibits excellent oxidation resistance with only 0.41 mg/cm2 of specific mass gain after 100 h oxidation, ascribed to the compact outer CrTi2O5 +TiO2 and inner Cr2O3 +nano-scale CrTi2O5 oxide layers. However, this oxide scale does not prevent the N from diffusion inward, forming the TiN and AlN in internal oxidation zone.