High-performance solid-state elastocaloric cooling materials with exceptional fatigue resistance are made possible by 3D printing a nickel-titanium based alloy, researchers report. According to the new study, the unique and intricate nanocomposite structures produced greatly enhance the efficiency and performance of the material for well over one million elastocaloric heat-pumping cycles, findings that indicate their potential use in contemporary refrigeration products and applications. Nearly one-fifth of the energy budget worldwide is spent on cooling and refrigeration, which is largely done using vapor compression, an inexpensive and mature technology; however, it is also limited in its efficiency and relies on refrigerants known to be greenhouse gasses. Solid-state cooling techniques suggest promising greener alternatives, particularly those that use mechanocaloric cooling materials, which could significantly surpass the energy efficiency of vapor compression. Elastocalorics, a type of mechanocaloric material, transfer latent heat when put under stress. However, repeated cycles of stress-induced heat pumping can lead to material fatigue or failure, limiting their long-term cooling performance and potential for widespread solid-state cooling applications. Huilong Hou and colleagues synthesized a nickel-titanium-based elastocaloric metal using laser directed-energy deposition (L-DED), a type of 3D printing that uses laser-melted metal powders to fabricate solid metal objects. Hou et al. discovered that the fusion of a nickel-rich blend of nickel and titanium powders resulted in a unique nanocomposite structure, which led to a considerable improvement in the resulting material's electrocaloric properties.