Elastocaloric effect by a weak first-order transformation associated with lattice softening in an Fe-31.2Pd (at.%) alloy

In typical shape memory alloys, significant elastocaloric effects appear in association with stress-induced martensitic transformations. However, we report here that in an Fe-31.2Pd (at.%) alloy, a significant elastocaloric effect appears due to lattice softening, which causes a weak first-order martensitic transformation at T0 (∼230 K). We found that in a wide temperature range of between 175 K (T0), the alloy exhibits an adiabatic temperature decrease of more than 1.5 K when a compressive stress of 200 MPa applied in the [0 0 1] direction is removed. The refrigeration capacity calculated in this temperature range is 5 MJ/m3.