Coercivity enhancement by inhibiting the formation of coarse grains region in hot-deformed Nd-Fe-B magnets with WC nano-particles addition

Anisotropic ultrafine-grained Nd-Fe-B magnets with WC addition were prepared by hot deformation. With WC nano-particles addition of similar to 1.0 wt.%, the squareness was optimized and the coercivity of the hot-deformed magnets increased substantially by 2.16 kOe, from 15.59 to 17.75 kOe without expense of the remanent magnetization. The observation for microstructure revealed that the WC nano-particles mainly existed on the interfaces of melt-spun ribbons. Meanwhile, due to the local compressive stress induced by the hard WC nano-particles, the deformability of neighboring grains was remarkably enhanced which leads to the reduction of the coarse grain regions. (C) 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.