A novel ultrafine-grained high entropy alloy with excellent combination of mechanical and soft magnetic properties

An ultrafine-grained FeCoNiCu0.2Si0.2 high entropy alloy (HEA) was designed and produced via melt-spinning. This HEA has Cu-rich cell-like grain structure with the size of 200-500 nm and Si-rich network-like intergranular structure with the width of 10-80 nm, leading to high yield strength and ultimate tensile strength of 820 MPa and 1100 MPa, respectively, as well as good plasticity. Moreover, it also shows high saturation magnetization, low coercivity and high Curie temperature. This ultrafine-grained HEA exhibits excellent combination of mechanical properties and soft magnetic properties among HEAs. Our work provides a novel route for designing high-strength soft magnetic HEAs, which is beneficial for the development of HEAs with soft magnetism and broadening their applications.