Mechanical and Magnetic Properties of Hot-Deformed Nd-Fe-B Magnets Doped with SiC Whiskers

Abstract

To improve the mechanical properties of hot-deformed Nd-Fe-B magnets, anisotropic Nd-Fe-B magnets doped with SiC whiskers were fabricated by hot-pressing and hot-deformation processes. The influence of the SiC whiskers on the microstructure and magnetic and mechanical properties of the Nd-Fe-B magnets was investigated. The bending strength of the hot-deformed Nd-Fe-B magnets reinforced with SiC whiskers first increased and then decreased with increasing SiC whisker content from 0 wt.% to 1.0 wt.%. The composite magnet with 0.5 wt.% SiC whiskers exhibited the highest average bending strength and still retained the maximum energy product of approximately 45.8 MGOe. The morphology of the fracture surface of the magnets revealed that the majority of the SiC whiskers were distributed at intergranular boundaries. The phenomenon of SiC whisker pullout from the matrix was observed, which results in increased bending strength. The improvement of the mechanical properties can be attributed to the high strength of the SiC whiskers, the whisker pullout phenomenon, and crack deflection.