グリーン冷却応用に向けた超弾性Ni-Ti合金の弾性熱量効果と相変態挙動

抄録

This study experimentally investigates the effects of thermal treatment on the elastocaloric effects and transformation behavior of superelastic Ni-Ti alloys, with the aim of developing eco-friendly green cooling technologies as an alternative to conventional methods. We focused on tube-shaped superelastic Ni_50.8Ti_49.2 (at.%) alloy, observing that short-time aging at 400°C resulted in improved mechanical properties and enhanced elastocaloric effects. It was suggested that these changes in the properties of the Ni-Ti alloy are primarily due to the precipitate morphology of Ni₄Ti₃ nanocrystals in the NiTi single phase, which significantly impacts the transformation temperature defining cooling performance. The ability to manipulate the austenite finish (A_f) temperature range, as evidenced in our findings, suggests potential for the development of cascade elastocaloric cooling systems through thermal treatment of a single composition Ni-Ti alloy. This study underscores the potential of Ni-Ti based superelastic shape memory alloys for future environmentally-friendly cooling applications.