Orientation dependence of elastocaloric effect in Ni50Mn30Ga20 single crystals

In this study, the orientation dependence of the elastocaloric effect and superelasticity in Ni50Mn30Ga20 single crystals undergoing L21-10M/14M-L10 martensitic transformations was investigated. The maximum value of the adiabatic temperature change delta Tad at reverse stress-induced martensitic transformations was shown to weakly depends on the orientation and equals 10.8 and 12.3 K in compression along the [001] and [011] directions, respectively. The superelasticity and elastocaloric effect temperature intervals were determined from the crystal orientation and were 80 K from 373 to 453 K for [001]-oriented crystals and 30 K from 373 to 403 K for [011]-oriented crystals. The strong orientation dependence of stress hysteresis delta sigma (delta sigma = 50-60 MPa for [001]-oriented crystals and delta sigma = 110-142 MPa for [011]-oriented crystals) did not significantly affect the delta Tad, but determined the efficiency of the material for practical use as a solid state cooling device. The factors influencing the delta Tad(T) dependence were analyzed. (c) 2021 Elsevier B.V. All rights reserved.

Automated summary

This study investigated the orientation dependence of the elastocaloric effect and superelasticity in Ni50Mn30Ga20 single crystals undergoing martensitic transformations. The adiabatic temperature change delta Tad was weakly dependent on orientation, while stress hysteresis delta sigma showed significant orientation dependence. These findings have implications for the practical efficiency of using the material as a solid state cooling device.