Tuning phase constitution and magnetic properties by composition in FeCoNiAlMn high-entropy alloys

Abstract While most studies on high-entropy alloys (HEAs) are focused on their potential applications as structural materials, the consideration in research as potential functional materials is still preliminary. This paper presents a comprehensive analysis of the microstructure, phase constitution and magnetic properties of the FeCoNi(AlMn)x (0.1 ≤ x ≤ 1.0) with the aim of developing the potential technological applications of HEAs soft magnetic materials. The results show that the addition of AlMn into FeCoNi alloy leads to the phase transition from FCC to BCC for the HEAs, which results in the increase of hardness and electrical resistivity (ρ). Owing to the synergistic effect of Al and Mn elements, the alloy with lower energy losses can be obtained when x = 0.5, whereas the alloy shows higher μi, μm, Bm, Ms, AC Bm when x = 1.0. Furthermore, compared with other soft magnetic materials, the FeCoNi(AlMn)x HEAs exhibit a superior combination of magnetic, electrical and mechanical properties. Therefore, this work showcases possible applications of each HEAs as soft magnetic materials in functional magnetic elements.