Elastocaloric cooling using shape memory alloy films

Abstract

The elastocaloric effect in magnetron-sputtered Ni50.4Ti49.6 films of 20 μm thickness is studied by means of uniaxial tensile tests and infrared thermography. For the investigated films, the usable quantity of latent heat is about 7.2 J/g. When relieving the stress after tensile loading and subsequent temperature equalization at strain rates larger than dε/dt = 0.2 s−1, a maximum temperature change of ΔT = −16 K is observed as expected for adiabatic conditions. Compared to bulk specimens, the heat transfer times are reduced to about 850 ms due to the larger surface-to-volume ratio, which is attractive for rapid cooling.