Fabrication and properties of soft magnetic Fe–Co–Ni–P–C–B bulk metallic glasses with high glass-forming ability

• FeCoNiPCB BMGs with dc of 2–2.5 mm and good soft magnetic properties are synthesized.
• The BMGs show low Tg below 687 K and large ΔTx up to 60 K.
• The BMGs exhibit low viscosity in the supercooled liquid state.
• The soft magnetic BMGs are advantageous for using as thermoplastic materials.
• The effects of Co and Ni addition in Fe-based BMGs are evaluated.

Soft magnetic Fe–Co–Ni–P–C–B bulk metallic glasses (BMGs) with good combination of superior glass-forming ability (GFA), low glass transition temperature (Tg) and large supercooled liquid region (ΔTx) were reported in this work. The experimental results show that the GFA and ΔTx of a Fe75P10C10B5 metallic glass can be enhanced effectively with the addition of Co and Ni elements, while the Tg is depressed. The (Fe, Co, Ni)75P10C10B5 fully glassy rods with diameters up to 2.5 mm can be achieved by copper mold casting, and the BMGs exhibit low Tg of 664–687 K, large ΔTx of 58–60 K, and low viscosity of 5.0–6.2 × 108 Pa·s in the supercooled liquid state, indicating high thermoplastic formability. Mechanical and magnetic measurements demonstrate that the (Fe, Co, Ni)75P10C10B5 BMGs exhibit high fracture strength of 2920–2990 MPa, and excellent soft magnetic properties, i.e., rather high saturation magnetization of 1.02–1.22 T and low coercive force of 3.8–5.2 A/m. The present Fe-based BMGs with good combination of superior properties are promising functional materials.