Investigating the elastocaloric effect of the NiTi fabricated by laser powder bed fusion: Effect of the building orientation

The elastocaloric effect of the Shape Memory Alloys (SMAs) is based on the reversible martensite phase change. Among all SMAs, NiTi has demonstrated superior performance in the elastocaloric effect. Recently, additive manufacturing has provided a new opportunity to enhance the elastocaloric effect of NiTi by creating porous structures, which increases heat transfer and reduces the required load. However, optimizing various parameters is crucial to achieving the highest elastocaloric effect in additive manufacturing. In this study, we conduct a novel investigation of the impact of building orientation on the elastocaloric effect of NiTi fabricated by the laser powder bed fusion (LPBF) technique. Samples in three different building orientations, including 〈001〉, 〈148〉, and 〈011〉, have been printed and tested experimentally at different strain levels to determine the magnitude of average adiabatic temperature change (ΔTadave) while monitoring the strain distribution. The result showed that the 〈001〉 sample with the ΔTadaveas high as 10.5 °C performed better than the others. However, the material characterization revealed that the presence of the inclusions in the 〈148〉 sample might significantly decrease its elastocaloric effect.