Synergistic effects of grain sizes on the corrosion behavior and mechanical properties in a metastable high-entropy alloy

Synergistic effects of grain sizes on corrosion behavior and mechanical properties of metastable high-entropy alloys (HEAs) were studied. The results exhibit that the corrosion resistance of metastable HEA increases first and then decreases with grain size increases. This difference in corrosion behavior is manifested in different degrees of passive film dissolution and pitting corrosion, and ascribed to characteristics of passive film induced by different grain boundary densities. Moreover, increasing the grain size decreases mechanical strength, suggesting a strong trade-off in matching corrosion resistance and mechanical properties. The potential corrosion mechanism and trade-off between corrosion resistance and mechanical properties were discussed.