Corrosion resistance and mechanism of high‐entropy alloys: A review

Environmental corrosion inevitably occurs during the use of alloys, making their corrosion resistance a special requirement for their application under specific conditions. The environmental corrosion behavior of alloys, seawater corrosion behavior, corrosion resistance, and microstructure of high‐entropy alloys (HEAs) have been prominent research topics over the past decade, all of which warrant further investigation. The corrosion resistance and passivation film strength of HEAs could be enhanced by improving their microstructure with appropriate adjustments of their elemental composition and content. In this review, the research status and corrosion mechanism of HEAs in seawater solutions with NaCl as the main component were examined. Moreover, the correlation between the microstructure, elemental composition, and corrosion resistance of HEAs was revealed. With the gradual increase of Al (1–4 at%), the corrosion of high‐entropy alloys initially exhibits small pits, the passive film breaks down and localized corrosion will appear later. When it varies between 4% and 10%, the pits will become larger, and even the localized corrosion will also appear initially.