Unraveling the oxidation mechanism of an AlCoCrFeNi high-entropy alloy at 1100 °C

This work aims to study the effect of elemental sluggish diffusion on the oxidation resistance of Al2O3-forming high-entropy alloys (HEAs). We compare the oxidation behavior of an AlCoCrFeNi HEA with that of two conventional Al2O3-forming alloys (FeCrAl and NiCoCrAl) and calculate the diffusivities of metal elements in the alloys using hybrid molecular dynamics (MD) and Monte Carlo (MC) simulations. It is clearly demonstrated in this study that the one order of magnitude lower diffusion rate of Al in the AlCoCrFeNi HEA is beneficial to lower the oxidation rate and inhibit the interface rumpling, thus improving the oxidation resistance.