Achieving excellent superelasticity and extraordinary elastocaloric effect in a directionally solidified Co-V-Ga alloy

We demonstrate excellent superelasticity and giant elastocaloric effect in a directionally solidified Co50.7V333Ga16 alloy. Owing to the formation of [001](A) preferentially oriented columnar grains, the as-grown alloy displays nearly perfect superelastic behaviors with fully reversible compressive strain of up to 5.4%, narrow stress hysteresis of about 40 MPa and a wide operating temperature window from 258 to 373 K. Simultaneously, a giant adiabatic temperature change Delta T-ad ad of -18.7 K is obtained on removing a uniaxial stress of 400 MPa at room temperature, which is in good agreement with the theoretical values based on Maxwell relation (-19.0 K) and calorimetric measurements (-19.9 K). A large vertical bar Delta T-ad vertical bar of greater than 12.5 K is obtained over a wide temperature span of at least 115 K. Moreover, both superelasticity and elastocaloric effect remain good functional stability without any evident degradation for 100 cycles. (C) 2021 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Automated summary

In this study, excellent superelasticity and giant elastocaloric effect were demonstrated in a directionally solidified Co50.7V333Ga16 alloy, showing reversible compressive strain, narrow stress hysteresis, and a wide operating temperature window. The alloy also exhibited a large adiabatic temperature change and good functional stability over multiple cycles.