Microstructure and mechanical properties of multi-component AlCrFeNiMox high-entropy alloys

Highlights: •The AlCrFeNiMo0.2 alloy was solidified at a relatively low cooling rate. •Its fracture strength and plastic strain are 3222 MPa, 0.287, respectively. •The FeCrMo-type σ phase is observed as a matrix phase. -- Abstract: The AlCrFeNiMox (x = 0, 0.2, 0.5, 0.8, 1.0) high entropy alloys were produced by vacuum arc melting, and their microstructure and mechanical properties were investigated. AlCrFeNi, AlCrFeNiMo0.2, and AlCrFeNiMo0.5 alloys contained two body centered cubic (BCC) phases which were AlNi-type intermetallic compound and FeCr-type solid solution. The diffraction peaks of the two BCC phases separated with the increase of Mo content while Mo element preferred to dissolve into FeCr-type solid solution. When the value of x was higher than 0.5, the FeCrMo-type σ phase appeared and replaced the FeCr-type solid solution. The AlCrFeNiMo0.2 had the highest fracture strength of 3222 MPa and plastic strain of 0.287. The hardness increased obviously from HV472.4 to HV911.5 with the addition of Mo element. The solid-solution strengthening of the BCC matrix and the σ phase hardening were the two main factors that strengthened the alloys. The AlCrFeNiMo0.2 high entropy alloy possesses the excellent mechanical properties which imply its potential application in industrial areas