High performance Fe-based nanocrystalline alloys with excellent thermal stability

Fe-based alloys are an important soft magnetic material that plays a pivotal role in a variety of energy-related industrial applications, such as electric transformers, motors and converters. However, the trade-off between magnetic softness and saturation magnetization (B_s) has been hindering the development of next-generation Fe-based soft magnetic materials. In this work, we demonstrate a facile route to obtain nanostructured Fe-based alloy out of a marginal glass former, which exhibits a core-shell like nanostructure and a synergetic increase of B_s, magnetic permeability (μ_e) and hardness upon thermal annealing, giving rise to a unique combination of B_s > 1.83 T, μ_e ∼25000 and ultrahigh hardness of ∼15 GPa. In terms of the combined magnetic/mechanical properties, the nanostructured Fe-based alloy outperforms the variety of Fe-based soft magnetic alloys hitherto reported. Furthermore, compared to the existing high performance soft magnetic Fe-based nanocrystalline alloys, the core-shell like nanostructure in our Fe-based nanocrystalline alloy displays an excellent thermal stability, which offers a large time window which would facilitate materials processing for future large-scale industrial production.