Microstructure and atmospheric oxidation behavior of CrCuFeMnNiCo x high‐entropy alloys fabricated by vacuum hot‐press sintering

• Published in: Materials and corrosion 2022-09, Vol.73 (9), p.1420-1429
• Main Authors: Ren, Bo, Zhao, Rui‐feng, Jiang, Ai‐yun, Yu, Yuan
• Format: Article
• Language: English
• ISSN: 0947-5117; 1521-4176
• DOI: 10.1002/maco.202213084

The CrCuFeMnNiCo x high‐entropy alloys (HEAs) were prepared by vacuum hot‐press sintering. The microstructure and atmospheric oxidation behavior at 800°C were studied. The phase structure of the Co 0 alloy comprised the Cr‐rich FCC1 major phase, Cu‐rich FCC2 secondary phase, and a small amount of intermetallic compound ρ phase when x  = 0. The bulk alloys comprised FCC2 major and FCC1 secondary phases when x  ≥ 0.5. The oxidation kinetics curves approximately followed the parabolic law. A high Co content leads to a large oxidation weight gain of the alloys. The oxidation weight gain of the Co 0 alloy was the smallest at approximately 4.46 mg cm −2 after atmospheric oxidation for 50 h, while the oxidation weight gain of the Co 2.0 alloy was the largest at approximately 5.94 mg cm −2 . The Co 0 alloys exhibited the best oxidation resistance. Therefore, Co is not beneficial to the improvement of the oxidation properties of the CrCuFeMnNiCo x HEAs. The main oxidation products of the HEAs mainly comprised MO, M 2 O 3, M 3 O 4 , and (M,Cr) 3 O 4 type metal oxides. The main oxidation mechanism was selective oxidation.