Oxidation behavior of CoCrFeMnNi high entropy alloy after plastic deformation

•Increasing plastic deformation degree will reduce the overall oxidation degree of HEA specimens.•Deformed HEA specimens experience oxidation mechanism transformation during oxidation.•Oxidation mechanism transformation is attributed to the recrystallization process.•Severe plastic deformation degree can introduce significant internal oxidation in the HEA. Oxidation kinetics of the plastically deformed CoCrFeMnNihigh entropy alloy (HEA) conforms to the multi-stage parabolic rate law, and the oxidation kinetics transition is triggered by the recrystallization. Since plastic deformation introduces abundant dislocations and vacancies, the oxidation initial rate gradually rises with increasing plastic deformation degree. As the oxidation process progresses, the deformed specmiens experience recrystallization, and specimens with larger plastic deformation degree form richer grain boundaries, which promotes the intergranular oxidation of Cr to form internal scales. The Cr-riched internal scales can effectively hinder the further oxidation and correspondingly reduce the overall oxidation degree of plastically deformed HEA specimens.