Effects of V Addition on Microstructural Evolution and Mechanical Properties of AlCrFe_(2)Ni_(2) High‑Entropy Alloys

摘要

The effects of vanadium addition on the microstructural evolution and mechanical properties of AlCrFe_(2)Ni_(2) high-entropy alloy(HEA)were investigated.The results showed that the AlCrFe_(2)Ni_(2)V_(0.2) HEA was composed of FCC phase,disordered BCC phase,and ordered BCC(B2)phase.With the increase in vanadium content,the formation of FCC phase was inhibited,and a transition from FCC phase to BCC phase occurred.The FCC phase disappeared completely when the value of x exceeds 0.4 in AlCrFe_(2)Ni_(2)V_(x) HEAs.Besides,the amplitude-modulated microstructure morphology transformed from a B2 phase matrix with dispersed BCC nano-phase into an alternating interconnected B2 and BCC phases.Vanadium element has the function of stabilizing BCC phase and B2 phase in AlCrFe_(2)Ni_(2)V_(x) alloys.The hardness of AlCrFe_(2)Ni_(2)V_(x) alloys increased from HV 332.4 to HV 590.7,while the yield strength increased from 765 to 1744.6 MPa with increasing vanadium content,which was mainly due to the decreasing content of FCC phase and the solid solution strengthening of vanadium element.At the same time,the compression ratio of the alloys decreased with the disappearance of the FCC phase.Among the alloys,the AlCrFe_(2)Ni_(2)V_(0.2) alloy possessed the most excellent comprehensive mechanical properties with yield strength,fracture strength,and compressive ratio 1231.1,2861.9 MPa,and 44.5%,respectively.