EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

Recently the SMA and FeSMA field has attracted interest for solid state refrigeration applications. Among NiMnGa-based quaternary systems, NiMnGaCu exhibits an interesting giant magnetocaloric effect thanks to the temperature overlapping of magnetic transition and thermoelastic martensitic transformation (TMT), in particular for compositions with about 6at% Cu content. In the present work in polycrystalline alloy samples with Ni50Mn18.5Cu6.5Ga25 at% chemical composition, we investigate the contribution of TMT to the total deltaS change in the elastocaloric performances, to give a functional characterization of effect of microstructure on caloric properties and to give another term of comparison for the magnetocaloric properties. We present an extensive calorimetric and thermo-mechanical characterization to explore the correlation between microstructural properties induced by means of selected thermal treatments and elastocaloric response. Our results give important hints on how the efficiency of the martensitic transition and its modulation in temperature has a final effect on the total DeltaS measured.