Interplay of the laser energy density and microstructure on the properties of NdFeB manufactured by laser powder bed fusion: a review

Abstract

As the permanent magnet material with the highest maximum energy product, NdFeB faces urgent demands in new energy vehicles and wind power generation, while conventional manufacturing processes encounter limitations in fabricating its complex geometries. Laser powder bed fusion technology offers an innovative solution for the precision manufacturing of NdFeB magnets owing to its high design flexibility and near-net-shaping capabilities. This review systematically summarizes the research advancements in LPBF-fabricated NdFeB permanent magnets over the past decade. First, it elucidates the synergistic mechanisms between the laser energy density and spot diameter, clarifying their impacts on the melt pool morphology and relative density. The defect suppression mechanisms are thoroughly investigated through scan strategy optimization, melt pool remelting, and substrate preheating. Subsequently, the mechanisms of heat treatment and hot isostatic pressing processes for regulating the microstructures and enhancing the magnetic properties are analyzed. Current achievements in the magnetic and mechanical performance of LPBF-processed NdFeB are systematically summarized, with a particular emphasis on the correlation between microstructural evolution and magnetic behavior. Finally, by addressing existing bottlenecks in magnetic property regulation, this review proposes a coordinated development strategy combining powder material design and process innovation, providing theoretical foundations and technical pathways for the additive manufacturing of high-performance NdFeB magnets with complex architectures.