Grain structure related inhomogeneous elastocaloric effects in Cu–Al–Mn shape memory microwires

Abstract

An inhomogeneous elastocaloric effect has been found and investigated in the present Cu–Al–Mn shape memory microwires by using the combined technique of infrared thermography and electron backscatter diffraction. Upon unloading, a reversible temperature change of ~5 K has been detected within the 5 mm gauge length. Inhomogeneous temperature distribution can be directly observed on the surface of microwires through infrared thermography measurement. Different regions of the microwires, involving bi-crystalline, oligo-crystalline, single-crystalline and poly-crystalline grain architectures, display different eCE cyclic stability, which can be ascribed to the heterogeneous grain architectures, the discrepancy of grain orientation and the varied neighboring grain constraints.