▎ 摘　　要

Single layer graphene (SLG) has been selected as an additive to modify the microstructure with integration of high anisotropy and grain refinement thereby improving magnetic properties of hot-deformed (HDed) Nd-Fe-B magnets. Careful STEM and HAADF analyses reveal that a new bi-morphologically anisotropic microstructure with fine grain size has been formed in the SLG-doped magnet, giving the omission of interfacial coarse grains. As a result, the coercivity of HDed Nd-Fe-B magnet has been significantly enhanced from 12.24 kOe to 17.05 kOe with addition of 0.1 wt% SLG and the remanence is almost unchanged with 13.19 kGs. The SLG mainly distributes on the interfaces of ribbons and acts as the medium of electronic and thermal conductor to avoid local overheating during hot-deformation process. It can inhibit the growth of Nd2Fe14B grains effectively and decrease or even eliminate the width of the coarse grain region, which is conducive to improving the magnetic properties of the hot-deformed Nd-Fe-B magnets. Our findings give further insight into the coercivity enhancement of HDed Nd-Fe-B magnets and provide a promising approach to realize high coercivity magnet with controllable microstructure from the combination of grain refinement and magnetic interaction.