Effect of Mo addition on microstructural evolution and corrosion behaviors of AlCrFeNi3 eutectic high-entropy alloy

The microstructural evolution and corrosion performance in chloride environments of as-cast AlCrFeNi3Mox (x = 0, 0.1, 0.2, 0.3, and 0.4 in molar ratio) high-entropy alloys (HEAs) were investigated. Results indicated that the microstructures of AlCrFeNi3Mox HEAs were transferred from FCC+B2 dual-phase eutectic microstructures (x = 0, 0.1, and 0.2) to bimodal eutectic microstructures (x = 0.3, 0.4), and the corrosion resistance of Mo-containing HEAs was superior to that of Mo-free HEA and 316 L SS. The AlCrFeNi3Mo0.3 HEA exhibited the superior anti-corrosion properties attributed to dense passive film enrichment of Cr2O3 and MoO3. Additionally, all HEAs displayed micro-galvanic corrosion behavior, with the B2 phase dissolving preferentially.