Ultra-wide working temperature range of elastocaloric effect in a (Ti25Zr10Hf15Ni25Cu25)99.6B0.4 high entropy shape memory alloy

Shape memory alloys exhibit elastocaloric effect by exploiting the latent heat along with stress-induced martensitic transformation, making them suitable for use as refrigerants of solid-state elastocaloric cooling technology. In view of practical application, it is of great importance to explore high-performance elastocaloric materials that simultaneously achieve large elastocaloric effect and broad working temperature range. In this study, a novel boron-doped (Ti25Zr10Hf15Ni25Cu25)99.6B0.4 high-entropy shape memory alloy is developed, by utilizing the severe lattice distortion of high entropy concept as well as the introduction of boron to enhance the mechanical properties. Consequently, large elastocaloric effect, with a maximum temperature change induced by external loading as high as 17.1 K, is attained over an ultra-wide temperature span ranging from 233 K to 473 K, being superior to those of most elastocaloric materials.