Influence of process parameters on the microstructure of laser printed NdFeB alloys

•Comprehensive characterization of Laser Printed 3D NdFeB magnets.•Correlation between laser parameters and solidification microstructure.•Identification of relevant crystallographic phases.•Improvement of magnetic properties by post fabrication heat treatments.•3D-printed NdFeB magnets (13.3 at.% RE) with HcJ = 551 kA/m and Br = 0.55 T. In this study, a methodology, based on the realization of single-track beads to the elaboration of 3D parts, was implemented in order to understand the microstructure of the laser printed NdFeB permanent magnets. An homemade powder was used, and the microstructures of the elaborated samples were characterized. For 3D parts measurement of the magnetic properties with various heat treatments were also carried out. The results demonstrate the effect of the laser parameters on the microstructure, especially on iron nucleation and on the transition from columnar to equiaxed growth. After an optimized heat treatment, the printed magnets exhibit a coercivity HcJ = 551 kA/m, a remanence Br = 0.55 T and an energy product (BH)max = 38 kJ.m−3.