Microstructure Dependence of Magnetic Properties for Al1.5Fe3Co3Cr1 Multi-Principal-Element Alloy

This study focuses on the microstructures and soft-magnetic properties of the Al1.5Fe3Co3Cr1 multi-principal-element alloy (MPEA) in different states. The MPEA was prepared using arc melting and suction-casting, followed by various heat treatments. The crystal structures were analyzed using X-ray diffraction (XRD), while the microstructures were characterized by means of transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The results reveal that the MPEA consists mainly of coherent body-centered cubic (BCC) and B2 phases, with a moderate lattice misfit (ε = 0.14~0.21%) between them. The homogenized alloy shows the presence of coarse equiaxed grains and micro-scale cells, and it has good soft-magnetic properties with MS = 127 emu/g and HC = 143.3 A/m (1.8 Oe). The thermal stability of the alloy is found to be optimal after aging at 873 K, as there are no significant changes in microstructures and soft-magnetic properties. However, when the aging temperature increases to 973 K, the BCC nanoprecipitates are coarsened, leading to a decrease in the soft-magnetic properties.