Porous NiTi Chips Fabricated by Laser Cutting and Stamping for Next-Generation Elastocaloric Cooling

Abstract Elastocaloric cooling (eC) using shape memory alloy (SMA) is a greenhouse gas-free alternative to conventional vapor-compression refrigeration. Stress-induced eC effect requires that the SMA refrigerants structure have both high heat transfer efficiency and robust mechanical stability. In this work, we fabricate porous refrigerants from NiTi SMA thin sheet using laser cutting and stamping. A maximum adiabatic temperature drop of 23.4 K under 900 MPa compression is achieved in NiTi refrigerant. Compared to existing wire-cutting techniques, our method increases processing speed by at least one order of magnitude and achieves 90% reduction in cost. Moreover, the stacked laser-cut-sheet structure exhibited no significant sign of failure over 10,000 eC cycles, demonstrating an enhanced fatigue resistance. Our work provides a new perspective on the design and fabrication of eC refrigerant structures, bringing this technology one step closer to commercial applications.