High-entropy alloys: a review of mechanical properties and deformation mechanisms at cryogenic temperatures

High-entropy alloys (HEAs) are multi-component alloys with a novel designed concept. These HEAs exhibit unique composition design and structural characteristics leading to excellent properties, which have attracted considerable attention in various fields. The extensively investigated HEAs exhibit excellent strength-ductility combination and excellent damage resistance at cryogenic temperature. Therefore, HEAs have potential applications in cryogenic temperature structural materials. It is important to study their deformation behavior and microstructural evolution at cryogenic temperature to provide the understanding needed for further alloy development. In this paper, the effects of different phase structure, grain size and stacking fault energy (SFE) on cryogenic temperature deformation behavior are reviewed. The research and development of tensile, compressive and fracture toughness of HEAs at cryogenic temperature are briefly reviewed. We discuss how individual deformation mechanisms can compete or operate synergistically with each other during cryogenic temperature plastic deformation, including dislocation slip, strain-induced twin formation and strain-induced phase transformation. In addition, the future trends and some problems faced by HEAs at cryogenic temperature are discussed, and prospects of HEAs are put forward.