Fabrication and Soft Magnetic Properties of Fe-B-Si-Zr/Hf-Cu Nanocrystalline Alloys with High Glass-Forming Ability

The effects of minor alloying addition of Cu on the glass-forming ability and crystallization process of Fe71.7-xB16.7Si8.3Zr3.3Cux and Fe72.5-xB16.7Si8.3Hf2.5Cux (x = 0, 0.3, 0.7, 1.0 and 1.3; at%) alloys were investigated. It was found that the critical glass formation size of rod samples gradually decreased from 2.5 to 1 mm with increasing Cu content in these alloys. Single alpha-Fe phase nanocrystalline alloys were obtained after isothermal annealing the Fe-B-Si-Zr/Hf-Cu glassy alloys containing 0.7-1.0 at% Cu. The Fe71B16.7Si8.3Zr3.3Cu0.7 alloy exhibited good soft magnetic properties with a high saturation magnetization ( 1.22 T) and a low coercive force ( 0.6 A/m) after annealing at 853 K for 10 min due to the precipitation of alpha-Fe nanoparticles of 8 nm size in the glassy matrix. The structural evolution on annealing and the variation tendencies against Cu content of the glass transition temperature, thermal stability and glass-forming ability of the Fe-B-Si-Zr/Hf-Cu amorphous alloys were discussed using a dual-cluster local structure model.

Automated summary

The study investigated the effects of minor alloying addition of Cu on the glass-forming ability and crystallization process of Fe-based alloys. It was found that the addition of Cu could improve the glass-forming ability and result in the formation of single alpha-Fe phase nanocrystalline alloys with good soft magnetic properties.