Enhancement of the mechanical strength in laser powder bed fused La/Ce-rich La-Ce-Fe-Co-Si magnetocaloric materials via crack healing

Laser powder bed fusion (LPBF) has been recently adopted to prepare magnetocaloric La(Fe,Si) 13 -based alloys due to geometry design freedom and near-net-shape features. However, the as-printed sample showed pronounced cracks which hindered their application. Here, La/Ce-rich La-Ce-Fe-Co-Si alloys were prepared by LPBF and the microstructural evolution after 30 min of short annealing was investigated. The as-printed sample consisted of uniformly fine La/Ce-rich and α-Fe(Co,Si) phases with many cold cracks. Notably, these cracks were filled with La/Ce oxides during annealing, leading to a certain degree of healing. Owing to the crack healing effect and the fine microstructure, an excellent compressive strength of 570 MPa was obtained. The annealed samples contained 79.06 wt% of NaZn 13 -type phases, and the magnetic entropy change was −7.48 J·kg −1 ·K −1 for a magnetic field change of 0–5 T. This research presents a promising route of rare-earth rich composition design for obtaining high-strength La(Fe,Si) 13 -based magnetic refrigerants by the LPBF method. • Fine structure of La/Ce-rich (La,Ce) 1.5 (Fe,Co,Si) 13 magnetic refrigerant prepared by laser powder bed fusion. • Crack healing after short time annealing with excellent compressive mechanical strength of 570 MPa. • Significant amount of NaZn 13 -type phase is formed after annealing, ensuring the magnetocaloric effect