Corrosion and Passivation of Multi Principal Element Alloys in Aqueous Solutions
Multi-principal element alloys (MPEAs) offer the possibility of considerable degrees of freedom in the choice of alloying elements to produce either single or multi-phase solid solution alloys. A wide range of material properties, sometimes unique, have been observed based on the alloying elements selected and microstructures developed. However, a structure, composition, and processing paradigm governing the corrosion properties of MPEAs has not yet emerged. The quest for superior corrosion properties requires understanding of the fate of each element during corrosion and its subsequent functions. Gaps in knowledge exist regarding the (a) specific functions of each element, (b) effects of elements in unusual combinations, and (c) possible formation of complex protective oxides which regulate corrosion and breakdown. These issues are discussed with the goal of accelerating the understanding of the corrosion behavior in this class of materials.