Corrosion-resistant Cu-Fe-based immiscible medium-entropy alloy with tri-layer passivation

Here, a novel alloy design strategy for improving corrosion resistance of Al15(CuFeMn)85 (at%) immiscible dualphase medium-entropy alloy is proposed and verified experimentally. The corrosion resistance of the alloy significantly enhances with the addition of Cr. During the corrosion of the Cr-containing alloy, three different oxide layers of Cu-, Cr-, and Fe-rich oxide layers with a few nm thickness are sequentially formed as a layered structure. Such tri-layer oxide enhances corrosion resistance by shielding the surface of the matrix, and the corrosion resistance of the alloys is comparable to that of austenitic stainless steels.

Automated summary

A novel alloy design strategy for improving corrosion resistance of Al-Cu-Fe-Mn immiscible dual-phase medium-entropy alloy by adding Cr is proposed and experimentally verified. The corrosion resistance of the alloy is significantly enhanced, with tri-layer oxide layers of Cu-, Cr-, and Fe-rich oxides forming during corrosion, leading to comparable corrosion resistance to austenitic stainless steels.