A non-equiatomic FeNiCoCr high-entropy alloy with excellent anti-corrosion performance and strength-ductility synergy

The mechanical behavior and corrosion resistance of a newly developed non-equiatomic Fe40Ni20Co20Cr20 (at.%) high-entropy alloy (HEA) were investigated. Excellent strength-ductility synergy with fracture elongation of more than 70 % was found to be mediated by dislocation activities and nano-twinning. The alloy shows significantly improved corrosion resistance compared to the equiatomic FeMnNiCoCr HEA upon immersion testing, and higher electrochemical corrosion resistance than the 316L stainless steel in 0.1 M H2SO4 solution. Apart from a high content of Cr3+ in the passive film, the interaction between Co and other elements potentially leads to the formation of Co(Fe,Cr)2O4 and enhances the passive film stability.