Elastocaloric effect induced by the rubber-like behavior of nanocrystalline wires of a Ti-50.8Ni (at.%) alloy

Elastocaloric effects in shape memory alloys are usually caused by latent heat associated with the stress-induced martensitic transformation. We report here that the rubber-like behavior of the R-phase in nanocrystalline Ti50.8Ni (at.%) wires, realized by an aging heat treatment under tensile stress, also contributes a significant elastocaloric effect. The efficiency of the elastocaloric effect caused by the rubber-like behavior is higher than that caused by the stress-induced B2 <-> B19' transformations because of the small energy dissipation. The usage of the rubber-like behavior is a method to extend the temperature window of the elastocaloric effect in shape memory alloys. (C) 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.