Evolution of corrosion mechanism of 3d transition metal high entropy alloys: A review

High entropy alloys (HEAs) attracted intensive study as they exhibit remarkable properties in potentially harsh service conditions. In numerous performance evaluation indicators, corrosion susceptibility is a major concern when selecting materials for practical applications because it causes serious problems with safety and significant economic loss. This review paper primarily analyses the evolution of corrosion characteristics of 3d transition metal HEAs with various chemical compositions across different aqueous solutions. Additionally, the effect of the chemistry of materials on the corrosion characteristics of 3d transition metal HEAs across different aqueous solutions is also discussed. The 3d transition metal HEA elements considered in the analysis mainly include Al, Cr, Ni, Ti, and Co. Additionally, the other elements, such as N, Sn and rare earth were also discussed. Further, the evolution of corrosion susceptibility under different preparation methods was elaborated, including the manufacturing process and heat treatment. Specifically, the existence of oxidation film and its correlation with the change of corrosion resistance in 3d transition metal HEAs was explored. Finally, the prospects in the field of 3d transition metal HEAs corrosion research are put forward. The review article will provide a quick guide for researchers intending to work on the corrosion performance of 3d transition metal HEAs.