Abstract
? 2022 Elsevier B.V.Large lattice distortion is the design idea to obtain a high elastocaloric effect of shape memory alloys. In the present work, a new method of He ion irradiation is used to obtain a large lattice distortion, resulting in a 6.5 K of adiabatic temperature in Ti-Ni microwires, compared to the 2.9 K of the unirradiated sample. In addition, the isothermal entropy change is 68 J/kg·K at 293 K, which is twice as high as that of unirradiated alternatives. The microwires have a larger unit cell lattice distortion after irradiation across the stress-induced martensite transformation, therefore, the irradiated sample has a larger lattice entropy change, resulting in the improvement of the phase transformation entropy change. This is the main reason that the elastocaloric effect of Ti-Ni shape memory microwires is significantly improved after He ion irradiation. This method will provide a new idea for the design of colossal elastocaloric effect materials and provide the possibility for the application of solid-state refrigeration.
NSTL
Elsevier