HDDR钕铁硼材料各向异性产生的机制

Mechanisms of producing anisotropy in NdFeB material during HDDR process

研究了NdFeB铸态粉末及HDDR工艺处理过程中不同阶段材料的显微结构、磁性能和各向异性产生的机理.发现NdFeB铸态粉末的各向异性均大于HDDR NdFeB材料的各向异性.随歧化时间延长HDDR NdFeB材料的各向异性单调下降,最终消失,说明HDDR NdFeB材料的各向异性来源于对铸态粉末各向异性的继承;短时间的歧化处理有助于材料获得各向异性;柱状歧化组织作为各向异性的传递介质,以位向关系的方式,将各向异性由铸态粉末传递到了经HDDR处理后的NdFeB粉末.

The microstructure, magnetic property and anisotropic mechanism of NdFeB as-cast powder and the material in different HDDR treatment stages were investigated. It is found that the anisotropy of NdFeB as- cast powder is greater than that of HDDR NdFeB materiacs. The anisotropy of HDDR NdFeB material decreases monotonously and finally disappears with the disproportionation time prolonging, which means that the anisotropy of HDDR NdFeB material originates from as-cast texture. Short disproportionation time is helpful for the anisotropy attainment. As an anisotropy passing medium, the disproportionation lamella microstructure transfers the anisotropy of as-cast powder to the final HDDR NdFeB material by means of crystallographic orientation.