Elastocaloric effect in bamboo-grained Cu71.1Al17.2Mn11.7 microwires

Abstract

Bamboo-grained Cu71.1Al17.2Mn11.7 microwires with diameter ∼150 μm were created by Taylor-Ulitovsky method and subsequent annealing. The grain architecture dependent superelasticity (SE) and elastocaloric effects (eCE) were confirmed. The bamboo-grained microwires exhibited low stress hysteresis loss during SE due to the reduced constraints caused by grain boundary, which is favorable for the mobility of martensite-austenite interface. Consequently, a large isothermal entropy change ∼21 J/kg K with a wide temperature range 90 K was achieved. The produced adiabatic temperature change (ΔTad) reached −11.9 K under a maximum stress 400 MPa. A stable ΔTad of −5.6 K showing little degradation in 200 eCE cycles was found with applied stress 325 MPa. This work reveals a fact that the bamboo-grained Cu–Al–Mn microwire may act as a desirable material for miniature solid-state refrigeration devices.