Laser powder bed fusion of the Ni-Mn-Sn Heusler alloy for magnetic refrigeration applications
Kun Sun, Abd El-Moez A. Mohamed, Sheng Li, Minki Jeong, Jake Head, Moataz M. Attallah
Abstract
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 (EV) of 18.52 J/mm3, 53.33 J/mm3 and 89.89 J/mm3, where they achieved a density of 6.8 g/cm3, 8.2 g/cm3 and 8.3 g/cm3, respectively. After heat treatment, the three samples show the L21 phase with a minor 4 O orthorhombic phase and double magnetic transitions, martensitie-austenite transition (TM) and curie temperature (TCA). The maximum magnetic entropy change (ΔSmax) values of the three samples around TM are 0.53 Jkg-1 K-1 at 160 K, 0.5 Jkg-1 K-1 at 130 K, and 0.3 Jkg-1 K-1 at 170 K, respectively. And ΔSmax of almost 1.0 Jkg-1 K-1 at TCA (∼320 K) for these samples with a field change of 1 T.