Suppression of twinning mechanism on nanoscale: size effect in Cu-Ni-Al shape memory alloy

0509149 - FZÚ 2020 RIV US eng J - Journal Article
Vronka, Marek - Karlík, M. - Veselý, J. - Maňák, Jan - Heczko, Oleg
Suppression of twinning mechanism on nanoscale: size effect in Cu-Ni-Al shape memory alloy.
Journal of Materials Science. Roč. 54, č. 8 (2019), s. 6586-6593. ISSN 0022-2461. E-ISSN 1573-4803
R&D Projects: GA ČR GB14-36566G; GA MŠMT LM2015087
Institutional support: RVO:68378271
Keywords : size effect * twinning * shape memory alloys (SMA) * in situ TEM/SEM compression tests
OECD category: Condensed matter physics (including formerly solid state physics, supercond.)
Impact factor: 3.553, year: 2019
Method of publishing: Limited access
https://doi.org/10.1007/s10853-018-03296-5

In Cu–Ni–Al shape memory alloy, we observed a significant size effect on the twinning stress, i.e. the dependency of compression stress needed for twin-variant reorientation on sample size using in situ loading of micro- and nanoscale pillars in scanning and transmission electron microscopes. With decreasing dimensions of pillars, the twinning stress sharply increases following scaling power law with an exponent approximately n = − 2/3. For very small nanopillars, the projected twinning stress is so high that the nanopillars are deformed by plastic deformation instead of twinning. Our results shed light on some of the fundamental aspects of nanoscale behaviour of shape memory alloys which is important for applications in microelectromechanical systems.
Permanent Link: http://hdl.handle.net/11104/0299921