Abstract Laser based powder bed fusion is a promising manufacturing method that can be used for the fabrication of hard magnets such as NdFeB with nearly any given geometrical shape. However, the weak performance, e.g., low coercivity, of the 3D-printed magnets currently hinder their application. In this work, we demonstrated a proof-of-concept of powder bed additive manufacturing of heavy rare earth free NdFeB magnets with technologically attractive coercivity values. The 3D-printed NdFeB magnets exhibit the highest (up-to-date for the additively manufactured magnets without heavy rare earth metals) coercivity values reaching μ0Hc = 1.6 T. The magnets were synthesized using a mixture of the NdFeB-based and the low-melting eutectic alloy powders. The essential function of the eutectic alloy, along with binding of the NdFeB-based magnetic particles, is the significant improvement of their coercivity by the in-situ grain boundary (GB) infiltration. The fundamental understanding of the magnetization reversal processes in these 3D-printed magnets leads to the conclusion that the excellent performance of the additively manufactured hard magnets can be achieved through the delicate control of the intergrain exchange interaction between the grains of the Nd2Fe14B phase.

中文翻译：

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无重稀土高矫顽力永磁体的增材制造

摘要 基于激光的粉末床融合是一种很有前途的制造方法，可用于制造几乎任何给定几何形状的硬磁体，例如 NdFeB。然而，3D 打印磁体的弱性能，例如低矫顽力，目前阻碍了它们的应用。在这项工作中，我们展示了具有技术上有吸引力的矫顽力值的无重稀土 NdFeB 磁体的粉末床增材制造的概念验证。3D 打印的 NdFeB 磁体表现出最高（最新的不含重稀土金属的增材制造磁体）矫顽力值达到 μ0Hc = 1.6 T。这些磁体是使用 NdFeB 基和低-熔化共晶合金粉末。共晶合金的基本功能，以及 NdFeB 基磁性颗粒的结合，是通过原位晶界 (GB) 渗透显着提高了它们的矫顽力。对这些 3D 打印磁体中磁化反转过程的基本理解得出的结论是，通过精细控制 Nd2Fe14B 相晶粒之间的晶间交换相互作用，可以实现增材制造硬磁体的优异性能。