Effect of Co on the microstructure and oxidation behavior of CoxCrCuFeMnNi high entropy alloy powders

The microstructure, phase, alloying behavior, and oxidation behavior of the CoxCrCuFeMnNi (x = 0, 0.5, 1.0, 1.5, 2.0, named as Co-0, Co-0.5, Co-1.0, Co-1.5, and Co-0.5, respectively) high entropy alloy powders (HEAPs) prepared by mechanical alloying were studied. The results indicated that the HEAPs began to be alloyed after ball milling for 5 h, and the particle size is about 40 similar to 60 mu m. After 50 h of milling, the Co-0 and Co-0.5 HEAPs are composed of metastable FCC and minor BCC solid solution phases, while the other HEAPs consist of single metastable FCC solid solution phase. After vacuum annealing or atmospheric oxidation at 700 degrees C, the metastable FCC and BCC phases decompose into FCC1 and FCC2 and rho phases, respectively. The oxidation mass gain of CoxCrCuFeMnNi HEAPs shows a parabolic upward trend. With the increase of Co content, the oxidation rate constant decreases, indicating that the oxidation resistance of the HEAPs decreases with the increase of Co content.

Automated summary

The microstructure, phase, alloying behavior, and oxidation behavior of CoxCrCuFeMnNi high entropy alloy powders with different Co content were studied. The results showed that the alloying began after 5 hours of ball milling and the oxidation resistance decreased with the increase of Co content.