High cyclic stability of the elastocaloric effect in sputtered TiNiCu shape memory films

The elastocaloric effect that occurs during the stress-induced martensitic transformation in shape memory alloys is a promising mechanism in view of solid state cooling applications. It also allows for downscaling to feature sizes in the mu m range, thus, being attractive for micro-cooling applications using thin film materials. In this study, elastocaloric properties of TiNi and TiNiCu films and their relation to functional fatigue were investigated. Both materials show similar effect sizes, their fatigue behavior is however different. While the temperature change in TiNi degrades by a factor of two within 150 cycles, no significant elastocaloric fatigue was found in TiNiCu. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4748307]