Exceptional Soft Magnetic Properties of an Ordered Multi-principal Element Alloy with Disordered Nanoprecipitates

In this work, a new non-equiatomic multi-principal element alloy (MPEA) Fe40Co30Mn15Al15 with excellent soft magnetic performance was fabricated. The microstructure and magnetic behavior of the as-cast alloy were investigated experimentally and theoretically using synchrotron X-ray diffraction, transmission electron microscopy, atom probe tomography, vibrating sample magnetometry, and density functional theory calculations. The alloy consists of an ordered B2-phase matrix enriched with Co/Al and uniformly distributed BCC nanoprecipitates enriched with Fe/Mn. The new alloy exhibits a high saturation magnetization of ~ 158 Am2/kg, a low coercivity of ~ 108 A/m, a high electrical resistivity of ~ 238 µΩ cm, and a high Curie temperature of ~ 1020 K, which shows an excellent combination of soft magnetic properties compared to previously reported MPEAs and conventional FeCo alloys. The findings thus provide a new perspective for designing high-performance materials for soft magnetic applications.