采用热压/热变形工艺制备纳米复合Nd9Fe84.5Co1B5.5永磁体,研究了热变形过程中的变形量对磁体平均晶粒尺寸的影响以及由此带来的晶间相互作用和矫顽力的变化。结果表明变形量54%的磁体中的硬、软磁性相的平均晶粒尺寸分别为61.0和51.8nm,与其热压状态时的两相平均晶粒尺寸（52.1和54.0nm）接近;而变形量74%的磁体中的硬、软磁性相的平均晶粒尺寸则分别显著减小至19.2和22.4nm。随着两相晶粒尺寸的显著细化,磁体中的晶间相互作用由以静磁耦合作用为主转变为以晶间交换耦合作用为主,这导致其矫顽力提高了64%。
Nanocomposite Nd9Fe84.5Co1B5.5 magnets were prepared by hot pressed/die-upset process.The effects of deformation ratios on the average grain sizes of hard and soft magnetic phases and the resulting changes of intergranular interaction and intrinsic coercivity in the magnets have been studied.The results show that the average grain sizes of hard and soft magnetic phases in the die-upset magnets at the deformation ratio of 54% are 61.0 and 51.8nm respectively,approaching those（52.1 and 54.0nm） in the hot-pressed ones.However they are greatly reduced to 19.23 and 22.36nm respectively at the deformation ratio of 74%.Comprehending with the outstanding refinement of the average grain sizes in the magnets,the intergranular interaction between hard and soft phase changes from magnetostatic-coupling interaction in controlling to exchange-coupling interaction in controlling,resulting in an enhancement of intrinsic coercivity with 64%.
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