Large elastocaloric effect in as-cast Ni-Mn-Sn-Fe ferromagnetic shape memory alloys

The Ni-Mn-Sn ferromagnetic shape memory alloys exhibit excellent both magnetic field-induced magnetocaloric effect and uniaxial stress-induced elastocaloric effect. However, the intrinsic brittleness and narrow refrigeration temperature regions hinder their practical applications in elastocaloric and magnetocaloric as well other fields. In this work, the as-cast Ni44-xFexMn46Sn10 (x = 1, 2, 3) alloys are prepared directly by cooling solidification. The as-cast alloys improve the mechanical properties and broaden the martensitic transformation temperature region due to the presence of dendrites. The dendrites prevent cracking formation and propagation along the grain boundaries, and the addition of Fe-atoms enriched in the interdendritic region further optimizes the mechanical performance. In addition, the as-cast Ni41Fe3Mn46 Snio alloy exhibits a large adiabatic temperature variation up to -10.3 K at a moderate stress of 350 MPa. Accordingly, direct cooling solidification of as-cast alloys could be a novel and feasible method for studying elastocaloric cooling technology. (C) 2022 Elsevier B.V. All rights reserved.

Automated summary

In this study, as-cast Ni-Mn-Sn alloys were prepared by direct cooling solidification, which improved the mechanical properties and broadened the martensitic transformation temperature range. The addition of Fe atoms further optimized the mechanical performance. The as-cast alloys exhibited good elastocaloric performance with a wide adiabatic temperature variation range.