晶粒细化对钕铁硼磁性能及力学性能影响
Study of Grain Refinement in Dy-Free Nd-Fe-B Sintered Magnet
摘要: 本研究通过粉末粒度的控制制备出了A、B两种不同晶粒尺的烧结钕铁硼样品，并对比分析了他们的磁性能、晶粒尺寸分布及力学特性。结果发现，晶粒细化使磁体的矫顽力从1115.7 kA/m提升至1339.3 kA/m，而剩磁几乎没有变化，烧结磁体的平均晶粒尺寸从8.57 μm减小至4.76 μm。晶粒细化使磁体的抗弯强度从422.98 Mpa提升至546.70 MPa，维氏硬度从577.30 HV增加至642.49 HV。晶粒细化使样品中晶界分布均匀密集，裂纹扩展途径发生改变，提高了磁体力学性能。
Abstract:
In the present work, A and B two types of Nd-Fe-B sintered magnet samples with different grain sizes were prepared by differentiating particle sizes, and the corresponding magnetic properties, grain size distributions and mechanical properties were compared. As a result, due to the grain refinement, the coercivity increased from 1115.7k A/m to 1339.3 kA/m while remanence almost unchanged, the average grain size decreased from 8.57 μm to 4.76 μm. Besides, bending strength and Vicker’s hardness of the magnet increased from 422.98 MPa and 577.30 HV to 546.70 MPa and 642.49 HV, respectively. Grain refinement made grain boundary distribute more tight and homogeneous, resulting in change of crack expansion route and enhancement of mechanical properties.
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