Preparation of a bulk Fe₈₃B₁₇ soft magnetic alloy by undercooling and copper-mold casting methods

Bulk Fe₈₃B₁₇ eutectic alloy rods with diameters up to 3 mm were prepared by undercooling solidification combined with Cu-mold casting. The results showed that the rapid solidification led to an increase in the nucleation rate, an inhibition of the grain growth and a competition between a stable Fe₂B phase and a metastable Fe₃B phase. Then, pure nano-lamellar eutectic microstructures and the metastable Fe₃B phase were successfully obtained in as-solidified alloys, which resulted in improved soft magnetic properties.