Research progress in elastocaloric effect and its application of NiTi-based shape memory alloys

Abstract

NiTi-based shape memory alloys (SMAs) are one of the SMAs with most outstanding properties, and have been widely applied in aviation, space, electronics, construction, biomedicine and other fields. In recent years, the elastocaloric refrigeration based on elastocaloric effect (eCE) of NiTi alloys has attracted increasing attentions since their excellent mechanical properties, huge elastocaloric strength and good machinability. However, conventional binary NiTi alloys cannot meet the requirements of long-life service since their large superelastic stress hysteresis and poor cyclic stability of superelasticity and eCE. In this paper, the research progress of eCE for NiTi-based alloys was reviewed. The effect of doping alloying element, thermomechanical treatment and novel processing techniques on eCE of NiTi-based alloys were surnmarized. In addition, the developed elastocaloric devices or prototypes based on NiTi-based alloys were also briefly introduced. However, the current researches on NiTi-based elastocaloric materials and the development of prototypes are still in the experimental stage. To realize their commercial application requires further in-depth research and optimization. In the future, the research priorities for the former will concentrate on material miniaturization, alloying or applying special treatment as well as changing circulation methods and so on. On the other hand, the research priorities for the latter will focus on improving heat transfer efficiency, strengthening heat exchange, reducing friction and other losses, and improving mechanical loadings as well as circulation modes.

Keywords

• niti-based alloys
• elastocaloric effect (ece)
• solid-state refrigeration
• r phase transition
• superelasticity
• cycling stability