Direct synthesis of Fe-Si-B-C -Cu nanocrystalline alloys with superior soft magnetic properties and ductile by melt-spinning

Structure, magnetic properties and ductile of melt-spun Fe 83- x Si 4 B 13- y C y Cu x ( x = 0-1.7; y = 0-8) alloys were investigated. The addition of 1.7 at.% Cu in a Fe 83 Si 4 B 13 amorphous alloy generates abundant alpha Fe crystals by providing nucleation sites, and further C doping promotes the growth of the crystals by suitable turning amorphous-forming ability, hence they increase saturation magnetic flux density ( B s ) and slightly worse magnetic softness of the as-spun alloys. The as-spun Fe 81.3 Si 4 B 7 C 6 Cu 1.7 alloy possesses a combined structure of a fully amorphous layer in wheel side surface and predominating nanocrystalline structure with gradually enlarged alpha-Fe crystal, whose average size and volume fraction are determined as about 12 nm and 32%, respectively, therefore superior soft magnetic properties and ductile with a high B s of 1.74 T, coercivity ( H c ) of 32.7 A/m, effective permeability ( mu e , at 1 kHz) of 3200 and high relatively strain at fracture ( epsilon f ) of 3.61% can be achieved directly in this alloy by only using melt-spinning. The annealing at 578 K releases internal stress, promotes the growth of the alpha-Fe crystals and remains the amorphous layer of the Fe 81.3 Si 4 B 7 C 6 Cu 1.7 alloy, then improves the soft magnetic properties and maintains the superior ductile with increasing the B s and mu e to 1.80 T and 14,100, respectively, lowering the H c to 9.4 A/m and slightly reducing the epsilon f to 2.39%. The combination of superior soft magnetic properties and ductile and simplified synthesis process entitles the Fe-Si-B-C -Cu nanocrystalline alloys great potentials in high performance electromagnetic applications. (c) 2022 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.

Automated summary

The structure, magnetic properties, and ductility of melt-spun Fe-Si-B-Cu alloys were investigated. The addition of Cu and C resulted in increased saturation magnetic flux density while slightly decreasing magnetic softness. The annealing process further improved the magnetic properties and maintained the ductility of the alloy.