Powder, process parameters and heat treatment conditions for Laser Beam Melting of LaFeSi-based alloys.

Shaping magnetocaloric alloys to thin-walled heat exchangers is a viable way to enhance the efficiency of magnetic cooling systems. In this study shaping of La(FeSi)13-based alloys is carried out by Laser Beam Melting (LBM), an Additive Manufacturing method which offers a high degree of geometrical flexibility. Hence this process could be used for a broad variation and optimization of the heat exchanger structures as well as for a small scale production for prototype systems. However, the adaption of the LBM process to La(FeSi)13-alloys requires careful choice of the base powder, the laser melting parameters and the conditions of the subsequent heat treatment. In this work, structures with wall thickness below 500 μm are successfully produced from both La(FeSiCo)13 and LaCe(FeMnSi)13, and the effect of the particle size and composition of the powder and the laser melting parameters is investigated. Additionally, the magnetocaloric entropy change after the heat treatment is reported.