A Strong and Plastic Fe-Based Composite Alloy with Extremely High Saturation Magnetic Flux Density by Constructing Multiscale Heterogeneous Structure

Abstract

For power electronic devices in high-energy-density and under mechanically demanding loading conditions, soft magnetic materials with high saturation magnetic flux density (Bs) and superior mechanical properties are needed. Yet, conventional Fe-based metallic glass is often constrained by poor formability, limited plasticity and relatively low Bs. This work introduces an innovative approach to fabricating amorphous-crystalline composites, achieved by ball milling hybridizing amorphous and crystalline powders, followed by spark plasma sintering. Through controlled elemental diffusion during sintering, the composite evolves into a phase-separated structure with densely packed interfaces composed of dual nanoscale grains. The resultant material not only exhibits remarkable compressive strength (i.e., a yield strength close to 1.4GPa) and exceptional plasticity (17.1%) but also attains a sufficiently high Bs (2.0T). Within our composites, deformation is deftly managed by diverse heterogeneous structures, where the synergistic effects of dislocation slip and nanotwinning effectively forestall catastrophic fracture. This research aspires to harmonize mechanical and magnetic properties by strategically constructing multiscale architectures.

Keywords: Fe-based metallic glass, mechanical property, high saturation magnetic flux density, saturation magnetic flux density