( 1. 宁波大学工程力学与材料科学系, 宁波 315211;
2. 南昌航空工业学院 材料科学与工程系, 南昌 330034)
摘 要: 研究当各向异性粉末烧结Nd15Fe77B8永磁体的磁化方向分别与x, y, z轴平行时, 其上激光熔凝层中Nd2Fe14B胞柱晶的易磁化轴的取向特征。采用XRD, SEM, Bitter粉纹等实验方法对粉末烧结Nd15Fe77B8永磁体表面的激光熔凝层进行了分析。结果表明: 当磁体的磁化方向分别与x, y轴平行时,其上激光熔凝层中Nd2Fe14B胞柱晶的易磁化轴具有与粉末烧结基体相同的取向;而当磁体的磁化方向与/z/轴平行时,其上激光熔凝层中的Nd2Fe14B胞柱晶的易磁化轴在xoy平面内随机分布。 在激光快速熔凝条件下,磁体表面激光熔凝层中的胞状Nd2Fe14B的择优生长方向为[100]晶向。
关键字: 激光表面熔凝; Nd2Fe14B;易磁化轴;晶体生长方向
cellular column Nd2Fe14B in laser melting/solidification pool on sintered Nd15Fe77B8 magnets
( 1. Department of Engineering Mechanics and Materials Science,
Ningbo University, Ningbo 315211, China;
2. Department of Materials Science and Engineering,
Nanchang Institute of Aeronautical Technology, Nanchang 330034, China)
Abstract: The arrangements of the easy magnetization axis [001] of cellular Nd2Fe14B of the cellular column zone in the laser melting/solidification pool, were investigated by XRD, SEM, and the Bitter method, on sintered Nd15-Fe77B8 magnets. The results show that the cellular columns of Nd2Fe14B at the zone are straight and parallel to z-axis. If the magnetization direction of the magnets is originally parallel to x, y-axis respectively, the cellular Nd2Fe14-B of the zone in the laser melting/solidification pool has the same arrangement of the easy magnetization axis as the magnets. But if the magnetization direction of the magnets is originally parallel to z-axis, the easy magnetization axis of the cellular Nd2Fe14B at the zone is in the xoy plane. And the preferential growth direction of all the cellular Nd2Fe14B in the laser melting/solidification pool is [100] under the condition of laser rapid solidification.
Key words: laser melting/solidification; Nd2Fe14B; easy magnetization axis; crystal growth direction