Microstructures, Hardness and Corrosion Behaviors of FeCoNiNb0.5Mo0.5 and FeCoNiNb High-Entropy Alloys

Abstract

This study investigates the effects of niobium and molybdenum on FeCoNi alloy, including on the microstructures and hardness of FeCoNiNb_0.5Mo_0.5 and FeCoNiNb alloys, and the polarization behaviors of these alloys in 1 M sulfuric acid and 1 M sodium chloride solutions. The results in this study indicate that both FeCoNiNb_0.5Mo_0.5 and FeCoNiNb alloys had a dual-phased dendritic microstructure; all of the phases in these alloys were solid solution phases, and no ordering was observed. Therefore, the solid solution effect significantly increased the hardness of these two alloys; in particular, FeCoNiNb alloy had the highest hardness of the alloys of interest. The corrosion resistance of FeCoNiNb_0.5Mo_0.5 and FeCoNiNb alloys was less than that of FeCoNi alloy because of their dual-phased dendritic microstructures. The corrosion resistance of the FeCoNiNb_0.5Mo_0.5 alloy exceeded that of the FeCoNiNb alloy in these solutions. However, FeCoNiNb_0.5Mo_0.5 and FeCoNiNb alloys exhibited a favorable combination of corrosion resistance and hardness.