Synthesis of a robust multifunctional composite with concurrent magnetocaloric effect and enhanced energy absorption capabilities through a tailored processing route

We report the synthesis and characterization of a multifunctional composite obtained by integrating micron-sized Ni52Mn26Ga22 Heusler alloy particles into a polysulfone matrix. The Heusler alloy powders were synthesized by the ball milling of as-spun Ni52Mn26Ga22 ribbons and subsequently incorporated into a polysulfone matrix using the solution casting process. The microstructural, magnetic and thermomechanical properties of the alloy-polymer composites were investigated. X-ray diffraction and transmission electron microscopy analyses revealed the presence of a 14M modulated crystal structure along with a hierarchical twinning system down to the atomic scale. Magneto-metric and thermomechanical testing revealed that the prepared composite demonstrates a magnetocaloric effect with a usable refrigeration capacity of 3.1 J/kg under a moderate magnetic field change of 1.38 T as well as a wideband energy absorption capability at a low 5 wt% loading. The disadvantages of bulk Ni-Mn-Ga single crystals such as inherent brittleness and difficulty of production may be overcome by the incorporation of micro-size particles into a flexible polymer matrix without compromising with its functional properties. Our work demonstrates a tailored processing route to obtain multifunctional composites for possible applications in spot cooling and broadband energy absorption.