Strength, plasticity and coercivity tradeoff in soft magnetic high-entropy alloys by multiple coherent interfaces

Traditional strengthening of alloys involves dislocation, second phase and grain boundary, which could deteriorate plasticity and coercivity ( H c ). In this work, multiple coherent interfaces are introduced in Fe 26 Co 25 Ni 20 Cu 15 Al 13.1 Ga 0.9 (denoted HEA2) soft magnetic high-entropy alloy, by which tradeoff among strength , plasticity and coercivity has been achieved. The strength is elevated to 414.6 MPa by the synergistic enhancement of FCC/BCC dual-phase interface, L1 2 nanoprecipitates in FCC phase and B2 nanoprecipitates in BCC phase. The fully coherent multiple interfaces (FCC/BCC, FCC/L1 2 and BCC/B2) bestow the HEA2 alloy with excellent plasticity exceeding 200%. More importantly, the smaller size of L1 2 and B2 nanoprecipitates than domain wall width and the multiple coherent interfaces wouldn't hinder domain wall movement, leading to a low coercivity of 334 A/m. Whereas, heterogeneous ordered B2 precipitates with size exceeding the critical width ( δ w = 132 nm) impose obvious pinning effect on the domain wall movement. This study provides guidance for developing novel alloys with balanced mechanical and magnetic properties for advanced electrical application.