Study on Elastocaloric Effects of Cu-rich Ni-Mn-Ti Polycrystalline Alloy

With the increasing global demand for energy conservation and emission reduction, elastocaloric refrigeration technology based on solid-state phase transformation has attracted widespread attention from researchers due to its environmentally friendly characteristics. This study designed Ni 50-x Mn 37.5 Ti 12.5 Cu x (x = 6, 7, 8, 9, 10) polycrystalline alloys to investigate the effect of high Cu content on the martensitic transformation and microstructure characteristics of Ni-Mn-Ti-Cu alloys. In as-cast Ni50-xMn 37.5 Ti 12.5 Cu x (x = 6, 7, 8, 9, 10) alloys, the gradual substitution of Ni by Cu leads to a decrease in martensitic transformation temperature, and a transition of the room-temperature phase from martensite to austenite with increasing Cu content. The polycrystalline Ni 41 Mn 37.5 Ti 12.5 Cu 9 alloy with a transformation temperature slightly below room temperature was selected for directional solidification treatment. At a test temperature of 315 K, a significant adiabatic temperature change Δ T ad of -24.1 K was detected by compressing the Ni 41 Mn 37.5 Ti 12.5 Cu 9 directionally solidified alloy.