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Evolution of temperature profiles in TiNi films for elastocaloric cooling.
- Source :
-
Acta Materialia . Dec2014, Vol. 81, p9-20. 12p. - Publication Year :
- 2014
-
Abstract
- The time-resolved strain and temperature profiles of magnetron-sputtered pseudoelastic TiNi films of 20 μm thickness are investigated during tensile stress cycling for different strain rates. Based on simultaneous infrared thermography and digital image correlation, a good correlation between the evolution of temperature profiles and the local formation and propagation of Lüders-like strain bands is observed. The evolution of temperature profiles can be quantitatively described by a phenomenological Tanaka-type model of the martensitic transformation combined with a heat transfer model taking into account the local interaction between transformed and untransformed regions in the transformation kinetics. The investigated film samples exhibit an undercooling of −16 K upon mechanical unloading under adiabatic conditions at a strain rate of 0.2 s −1 . A coefficient of performance of 7.7 is determined. Due to the high surface-to-volume ratio, the films show fast heat exchange in air of the order of 1.5 s. Based on these results, the prospects of SMA film-based elastocaloric cooling are discussed. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 13596454
- Volume :
- 81
- Database :
- Academic Search Index
- Journal :
- Acta Materialia
- Publication Type :
- Academic Journal
- Accession number :
- 99232092
- Full Text :
- https://doi.org/10.1016/j.actamat.2014.08.006