Thermal conductivity and specific heat capacity of austenite and stress‑induced martensite in superelastic NiTi at ambient temperature

0577408 - FZÚ 2024 RIV US eng J - Journal Article
Jury, A. - Balandraud, X. - Heller, Luděk
Thermal conductivity and specific heat capacity of austenite and stress‑induced martensite in superelastic NiTi at ambient temperature.
International Journal of Thermophysics. Roč. 44, č. 11 (2023), č. článku 162. ISSN 0195-928X. E-ISSN 1572-9567
R&D Projects: GA ČR(CZ) GA22-15763S
Institutional support: RVO:68378271
Keywords : austenite * heat source reconstruction * infrared thermography * shape memory alloy * stress-induced martensite * nickel-titanium
OECD category: Materials engineering
Impact factor: 2.2, year: 2022
Method of publishing: Limited access
https://doi.org/10.1007/s10765-023-03279-y

Infrared thermography (IRT) and heat source reconstruction (HSR) were used in the study to measure two thermophysical properties of superelastic nickel-titanium (NiTi) shape memory alloy (SMA) wires, namely thermal conductivity and specific heat capacity. A uniaxial testing machine was used to apply constant deformation while allowing temperature measurements by IRT during Joule heating and natural return the thermal equilibrium. The data processing by HSR, including preliminary filtering operations, was preliminarily evaluated from temperatures provided by a model (with added noise). It gave an error of ± 0.5% for the thermal conductivity and ± 1% for the specific heat capacity. The experimental analysis showed that the thermal conductivity of stress-induced martensite is 26% higher than that of austenite at the same temperature (here the ambient temperature). Regarding the specific heat capacity, that of stress-induced martensite is 4.7% lower than that of austenite.
Permanent Link: https://hdl.handle.net/11104/0346544