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

Ni Co Cr-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 the metastable γ ” phase in this alloy system and prevent it from transforming into a stable δphase at grain boundaries upon 650 °C aging, resulting in improved mechanical properties at elevated temperatures. The specific strength of γ ”-strengthened multi-component NiCoCr-based alloy can reach up to 86.2 MPa g-1cm-3at 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.