Superelasticity and elastocaloric effect of NiTiNb shape memory alloys over a wide working temperature window
Year: 2025
Type: article
Abstract: Solid-state refrigeration based on the elastocaloric effect is a promising alternative to conventional vapor-compression refrigeration technology due to its environmental friendliness and high energy-efficiency. NiTi-based shape memory alloys with a great elastocaloric effect in a wide working temperature window are particularly needed for solid-state refrigeration applications. In this study, a series of Ni50.8-xTi49.2Nbx (x = 0, 1, 2 and 3) shape memory alloys were fabricated via arc melting, followed by thermal treatment. The experimental results showed that the martensite transformation temperature decreases with increasing Nb content due to the stabilization of the parent phase by doped Nb atoms. Combining solution strengthening and precipitation strengthening of the Nb addition, the Ni48.8Ti46.2Nb2 alloy demonstrated a significant improvement in the critical stress for martensite transformation and transition strain over a large temperature range of 216 – 316 K. Meanwhile, it exhibited a large adiabatic temperature change of 24.13 K during rapid stress loading-unloading cycles. The Maxwell relation and Clausius-Clapeyron equation were employed to validate the large working temperature window and elastocaloric effect. These findings highlight the high potential of Nb-doping NiTi shape memory alloys for solid-state refrigerants.
Authors: Bailiang Qin, Ze Pu, Changyong Chen, Yongyun Zhang, K.C. Chan
Institutions: Hong Kong Polytechnic University, University of Hong Kong
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,640
Award: G1898397685
OpenAlex ID: W7082978808