The effect of thermal post-processing treatment on laser powder bed fusion processed NiMnSn-based alloy for magnetic refrigeration

This study investigates the effects of heat treatment (HT) time (one, two, and three weeks) on the micro-structure and magnetocaloric effect (MCE) of laser powder bed fusion (LPBF) NiMnSn alloys. Increasing the HT time improves chemical homogeneity, and decreases the local misorientation imparted by the LPBF process. This is also associated with an enhancement in the maximum magnetic entropy change (  Sm) values around the martensitic transformation temperature (TM), which increases from 0.2 J kg-1 K-1 to 0.45 J kg-1 K-1 under 1 T applied magnetic field. However, the  Sm of the one-week HTed sample around the curie temperature (Tc) (0.90 J kg-1K-1 at 315 K) is slightly lower than the two weeks and three weeks HTed samples (0.99 J kg-1K-1 at 320 K, 0.94 J kg-1K-1 at 320 K), respectively.& COPY; 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).