Microstructures and mechanical behavior of non-equiatomic Co29Cr29Fe29Ni13-xVx high-entropy alloys at room and cryogenic temperatures

Abstract

A series of non-equiatomic Co29Cr29Fe29Ni13-xVx (x = 0, 0.5, 3, and 5) high-entropy alloys (HEAs) with fully recrystallized microstructures were prepared by rolling and annealing. The microstructures were characterized and the mechanical properties were obtained at different temperatures. The recrystallization and grain-growth behavior of the alloys are retarded owing to the addition of V. The lattice friction stress increases drastically with the addition of a minor of V. Ultrahigh yield strengths of 1.8 GPa and 1.4 GPa, and considerable tensile ductility values of ∼30% and ∼50% were developed at a cryogenic temperature (77 K) for the 700 °C-annealed and 800 °C-annealed alloys. The strengthening mechanism and deformation behavior at cryogenic temperatures were investigated. The comprehensive mechanical properties of the alloy at low temperatures are better than those of most reported HEAs. The alloy is easy to process and prepare and therefore, has considerable potential for industrial applications.