Long-Term Stable Elastocaloric Effect in a Heusler-Type Co51V33Ga16 Polycrystalline Alloy

Cyclic stability is of utmost importance for the long-term work of caloric materials in solid-state refrigeration. Heusler-type shape memory alloys show a large elastocaloric effect under low driving stress, but their intrinsic brittleness always leads to poor cyclic stability. Here, we demonstrate the simultaneously achieved large elastocaloric effect and long-term cyclic stability in a Heusler-type Co51V33Ga16 polycrystal-line alloy. Over a wide temperature range of 290-340 K, large adiabatic temperature change (Delta Tad) values of -6.0 to -10.9 K can be obtained upon fast unloading. Moreover, by synthetically considering the influences of deformation parameters on the Delta Tad values, stress hysteresis, energy dissipation, and temporary residual strain to balance cooling capacity and cyclability, large Delta Tad values higher than 6.0 K are maintained for more than 50 000 superelastic cycles performed under the compressive strain of 3.5% and strain rate of 1.1 x 10-2 s-1, showing a very low degradation rate of 2 x 10-5 K per cycle. Such cyclic stability of elastocaloric effect well outperforms those reported in Heusler-type alloys so far.

Automated summary

This study demonstrates the large elastocaloric effect and long-term cyclic stability achieved in a Huesler-type Co51V33Ga16 polycrystalline alloy. The alloy shows large adiabatic temperature change values over a wide temperature range and maintains a low degradation rate during superelastic cycles, outperforming previously reported Huesler-type alloys.