Linkage between process-induced microstructure and magnetic property of Nd-Fe-B permanent magnets additively manufactured by laser powder bed fusion

• Grain morphology was governed by the G/R ratio at melt pool interior and boundary regions as the applied heat input. • Higher laser power induced grain coarsening and broadened Ti/Zr segregation with higher enrichment in the heat-affected zone (HAZ) • Process–microstructure–property relationships were systematically analyzed and clarified. Nd-Fe-B permanent magnets are widely used in high-performance electromagnetic applications due to their excellent magnetic properties. While conventional fabrication methods of Nd-Fe-B magnets such as sintering and hot deformation have been extensively studied, they impose limitations on design flexibility and material efficiency. Laser powder bed fusion (LPBF), an additive manufacturing technique, offers new possibilities for fabricating Nd-Fe-B magnets with tailored microstructures and enhanced performance. However, the correlation between process parameters, microstructural evolution, and magnetic properties remains insufficiently understood. This study investigates the effects of LPBF process parameters on the microstructural characteristics and magnetic performance of Nd-Fe-B magnets. Particular emphasis is placed on the hierarchical and heterogeneous microstructure formed in Nd-Fe-B magnets due to rapid solidification during LPBF, the influence of thermal gradients on grain morphology, and the impact of process-induced phase evolution on magnetic properties. The findings provide insights into optimizing fabrication parameters for achieving high-performance Nd-Fe-B magnets through LPBF.