Large thermal hysteresis in a single-phase NiTiNb shape memory alloy

Journal Article · 02 February 2022 · Scripta Materialia

DOI: https://doi.org/10.1016/j.scriptamat.2022.114574 · OSTI ID:1981752

Kang, Genfa ^[1]; Zhang, Hui ^[1]; Ma, Zhiyuan ^[1]; Ren, Yang ^[2]; Cui, Lishan ^[1]; Yu, Kaiyuan ^[1]

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1. China University of Petroleum-Beijing (China)
2. City University of Hong Kong (China)

Large thermal hysteresis ($$T$$_hys) is favorable in shape memory alloys (SMAs) because it renders wide service and storage temperature range of the SMA-made parts. In this letter, we show that large intrinsic $$T$$_hys up to 100 K is achieved in a low Nb content (2 at.%), β-Nb-free and single-phase NiTiNb SMA fabricated by casting, forging, wire-drawing and annealing. Such a large $$T$$_hys is comparable to that of the widely used dual-phase NiTiNb SMAs in which high Nb content and β-Nb are required. By exploiting the grain-size-dependence of $$T$$_hys in our single-phase NiTiNb SMA and that in an equiatomic NiTi SMA, we attribute the large $$T$$_hys to the enhanced kinetic resistance of transformation by the small grains. In conclusion, the connection between the $$T$$_hys and the kinetic resistance is demonstrated by a modified dislocation-based kinetic model.

• Research Organization: Argonne National Laboratory (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
• Sponsoring Organization: National Natural Science Foundation of China (NFSC); USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: AC02-06CH11357
• OSTI ID: 1981752
• Journal Information: Scripta Materialia, Journal Name: Scripta Materialia Journal Issue: C Vol. 212; ISSN 1359-6462
• Publisher: ElsevierCopyright Statement
• Country of Publication: United States
• Language: English