Ageing Hardening Mechanism and Corrosion Resistance in the Fe65Cr13Cu3(CoMnMoNiAlTi)19 Medium-Entropy Stainless Alloy

The ageing hardening mechanism of a newly designed Fe-Cr-based Fe65Cr13Cu3(CoMnMoNiAlTi)(19) medium-entropy stainless alloy (ME-SA) with a simple bcc solid solution matrix was studied. This kind of ME-SA possessed a higher ageing hardness of approximately 584 HV and higher compressive stress and corrosion resistance than those of the conventional precipitation hardening stainless steel 17-4PH (Cr17Ni4Cu4Nb), which has comparable compressive strain. The well-dispersed B2-ordered phase in the cast state transformed to a D0(3) crystal structure with a higher ordering degree and reduced the precipitate size after ageing at 500 degrees C, thus promoting a great ageing hardening effect.

Automated summary

The newly designed Fe-Cr-based medium-entropy stainless alloy exhibits high ageing hardness, compressive stress, and corrosion resistance compared to conventional precipitation hardening stainless steel. The transformation of the well-dispersed B2-ordered phase to a D0(3) crystal structure after ageing at 500 degrees Celsius results in a significant ageing hardening effect.