A strong and ductile cobalt-free solid-solution Fe30Ni30Mn30Cr10 multi-principal element alloy from hot rolling

Most of the face-centered cubic (FCC) multi-principal element alloys (MPEAs) developed thus far contain cobalt. For many applications, it is either required or beneficial to avoid cobalt, since cobalt has long-term activation issue (for nuclear applications), is expensive, and is considered a critical material. In addition, FCC structured solid-solution MPEAs tend to have relatively low strength. A FCC solid-solution Fe30Ni30Mn30Cr10 (at %) MPEA was fabricated via arc melting, followed by homogenization at 1100 °C for 12 h. The alloy was hot rolled at 1100 °C with a total reduction of up to 97 %. The microstructure was characterized and mechanical properties were investigated at various stages. Tensile testing showed that yield strength (YS) increased by 285–595 MPa and ultimate tensile strength (UTS) increased by 520–710 MPa. This increase in YS and UTS occurred with a total elongation (ductility) of 40 %. Meanwhile, hot rolling at high reductions led to evident decreases in size and area fraction of Mn-rich inclusions. Overall, after hot rolling, this FCC solid-solution MPEA is both strong and ductile