Formation and properties of Fe25Co25Ni25(P, C, B, Si)25 high-entropy bulk metallic glasses

New ferromagnetic high-entropy bulk metallic glasses (HE-BMGs) with superior glass-fanning ability (GFA) and high strength were developed in the pseudo quaternary FeCoNi(P, C, B, Si) system. The HE-BMG rods were fabricated by topper mold casting method in the composition range of Fe25Co25Ni25(P0.3-0.5C0.1-0.3B0.2-0.3Si0.1-0.3)(25), in which the Fe25Co25Ni25(P0.4C0.2B0.2Si0.2)(25) and Fe25Co25Ni25(P0.5C0.1B0.2Si0.2)(25) alloys Possess the largest critical diameter of 2.0 mm. The HE-BMGs exhibit excellent soft magnetic and mechanical properties, i.e., low coercivity of 0.8-2.1 A/m, high saturation magnetization of 0.80-0.86 T, high compressive yield strength of 2970-3076 MPa, and large plastic strain of 1.9-2.1%. The mechanisms of the high GFA and good magnetic softness of the alloys were discussed.