Microstructures and mechanical properties of the precipitation strengthened Al0.4Cr0.7FexNi2V0.2 high entropy alloys

Abstract

In this study, a series of Al0.4Cr0.7FexNi2V0.2 (x: molar ratio, x = 0.5, 1, 2) high entropy alloys were cold-rolled and annealed. The microstructures and mechanical properties of the alloys were systematically investigated. The results revealed that all the solution-treated alloys with different Fe contents exhibited solo FCC phase. After annealing, the coherent L12 phases and hard BCC phases were formed in the Fe0.5 and Fe1 alloys, while the Fe2 alloy only contained the L12 phases. The precipitation of L12 and BCC phases increased the hardness of the alloys. The volume fraction of BCC phase was found to decrease as the Fe content increased, the excessive BCC phases led to the decrease of plasticity. The mechanical properties of alloys were mostly determined by the degree of recrystallization and the amount and type of precipitates. The precipitation of the second phase was regulated by tailoring the alloy composition, so that the AN Fe1 alloy can obtain excellent mechanical properties.