Effects of V addition on the mechanical properties at elevated temperatures in a γ'-strengthened NiCoCr-based multi-component alloy

NiCoCr-based multi-component alloys have drawn much attention due to their exceptional ductility and strain hardening capacity. However, insufficient strength-ductility synergy of NiCoCr alloy has always been an issue that prevents it from extensive applications. According to our previous research, the precipitation of γ'' phase can significantly improve the strength-ductility synergy of this alloy system at room temperature. In this study, the effects of V addition on γ'' phase stability and high temperature mechanical properties have been explicitly investigated. The results indicate that V addition can stabilize metastable γ'' phase in this alloy system and prevent it from transforming into stable δ phase at grain boundaries upon 650 °C aging, resulting in improved mechanical properties at elevated temperature. The specific strength of γ''-strengthened multi-component NiCoCr-based alloy can reach up to 86.2 MPa/g•cm−3 at 650 °C, which is higher than those of Ni-based superalloys, IN 939 and Waspaloy. This work provides theoretical guidance for the novel design of γ''-strengthened alloy for high temperature applications.