Laser powder bed fusion of the Ni-Mn-Sn Heusler alloy for magnetic refrigeration applications

This study aims to develop a manufacturing route for a low-cost dense magnetocaloric Ni-Mn-Sn Heusler alloy (HA) using laser powder bed fusion (LPBF) additive manufacturing technique by in-situ alloying from its elemental constituents. LPBF enables the production of high surface-area-to-volume 3D-printed components to increase heat transfer efficiency in magnetic refrigerators. A laser parametric study was performed on blocks, lattices and microchanneled cylinders for maximum densification, the highest density was observed at the samples with laser energy density (E-V) of 18.52 J/mm(3), 53.33 J/mm(3) and 89.89 J/mm(3), where they achieved a density of 6.8 g/cm(3), 8.2 g/cm(3) and 8.3 g/cm(3), respectively. After heat treatment, the three samples show the L2(1) phase with a minor 4 O orthorhombic phase and double magnetic transitions, martensitie-austenite transition (T-M) and curie temperature (T-C(A)). The maximum magnetic entropy change (Delta S-max) values of the three samples around T-M are 0.53 Jkg(-1) K-1 at (1)60 K, 0.5 Jkg(-1) K-1 at 130 K, and 0.3 Jkg(-1) K-1 at 170 K, respectively. And Delta S-max of almost 1.0 Jkg(-1) K-1 at T-C(A) (similar to 320 K) for these samples with a field change of 1 T.