کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1445593 | 1509595 | 2014 | 12 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Evolution of temperature profiles in TiNi films for elastocaloric cooling Evolution of temperature profiles in TiNi films for elastocaloric cooling](/preview/png/1445593.png)
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.
Journal: Acta Materialia - Volume 81, December 2014, Pages 9–20