Effect of molybdenum content on the microstructure and corrosion behavior of FeCoCrNiMox high-entropy alloys

The effect of Mo content on the microstructure revolution and corrosion behavior of cast FeCoCrNiMoxhigh-entropy alloys in chloride environments were investigated. Results indicate that FeCoCrNi and FeCoCrNiMo0.1alloys are in single FCC solid solution. The precipitates form in FeCoCrNiMo0.3 and increase in FeCoCrNiMo0.6 alloys. Pitting occurs on FeCoCrNi and FeCoCrNiMo0.1alloys while FeCoCrNiMo0.3 and FeCoCrNiMo0.6alloys suffer from preferential localized corrosion at the regions depleted in Cr and Mo. The higher Cr2O3/Cr(OH)3 ratio and the incorporation of Mo oxides make the passive film more protective and the corrosion resistance of the FeCoCrNiMo0.1alloy is thus enhanced. The correlation between microstructure and corrosion behavior and the corresponding corrosion mechanism were clarified.