Microstructure, martensitic transformation and elastocaloric effect in Pd-In-Fe polycrystalline shape memory alloys

Abstract

In this work, we have investigated the microstructure, martensitic transformation, and elastocaloric effect of Pd-In-Fe polycrystalline alloys. For this new magnetic shape memory alloys, both phase constitution and morphology highly depend on the Fe content. Exhibiting a single austenite phase at room temperature, Pd59.3In23.2Fe17.5 alloy has a large superelastic cooling effect of −5.4 K with a low critical stress of 80 MPa to trigger the martensitic transformation. Interestingly, the onset of superelastic stress can be drastically reduced by mechanical training. The rare-earth/Mn-free and non-toxic element constitution, good ductility and tunable transformation temperature render the Pd-In-Fe Heusler system as a promising candidate for elastocaloric cooling.