Homogenization of Al CoCrFeNi high-entropy alloys with improved corrosion resistance

The present work investigates the homogenization effect of 1250 °C heat treatment on the AlxCoCrFeNi high-entropy alloys (HEAs). The multi-phase microstructures with chemical segregations are inevitable with the increased Al content in the alloys, which cause work function variations and localized corrosion. After heat treatment, the homogenization effect revealed by the microstructure simplification and chemical-segregation reduction leads to the decreased work function variations and the improved corrosion resistance. Thermodynamic calculations that are reliable to predict the phase transformations of the AlxCoCrFeNi HEAs, indicates a further enhancement in corrosion resistance through annealing could be guided for many other HEAs systems.