Elastocaloric properties of a solution-treated Ni-Ti-Ga shape memory alloy

Elastocaloric refrigeration technology, which exploits the caloric effect from stress-induced phase transformation in shape memory alloys for cooling, is widely regarded as one of the most promising environment-friendly alternatives to traditional vapor-compression cooling technology. Development of high-performance elastocaloric materials is of great significance for the advancement of elastocaloric refrigeration technology. In this work, we report a large elastocaloric effect in a bulk polycrystalline Ti_48.5Ni_46.5Ga₅ alloy prepared by simple casting and solution treatment, without complicated hot/cold working or ageing. This alloy shows a large adiabatic temperature change (ΔT_ad) of −24.8 K upon the release of a moderate stress of 500 MPa at room temperature, as well as a high yield strength of 1140 MPa. Furthermore, it exhibits very high specific adiabatic temperature change (|ΔT_ad/σ| = 49.6 K·GPa⁻¹). The large elastocaloric effect may be attributed to the high yield strength, favorable orientation, and relatively large latent heat. This alloy shows great potential as a highly energy-efficient solid-state refrigerant for novel elastocaloric cooling applications.