Oxidation behavior of Pt modified CoNiCrAl medium-entropy alloy under water vapour at 1100 °C

Pt modified CoNiCrAl medium-entropy alloys (MEAs) were optimized that displayed outstanding long-term oxidation resistance life at 1100 degrees C. Compared to air, introducing interstitial H into the Al 2 O 3 lattice changed the energy of Al vacancy formation, from 6.89 eV to 4.13 eV, indicating that water vapour accelerated the oxidation of MEAs, which was twice that of air. With the Pt increasing, the Young ' s modulus and hardness improved, promoting the formation of smoother Al 2 O 3 scale in 10Pt-MEA. Precipitation of Pt enrichment at the phase boundary suppressed oxygen diffusion and reduced oxidation rate. The designed MEAs expand the application of high/medium-entropy alloys.