Blocking of martensitic transition at the nano-scale in the Ti2NiCu wedge

Abstract

Shape memory effect associated with martensitic transformations is of the rapidly developing field in nanotechnologies, where industrial use of systems established on that effect provide greater flexibility on the nano-devices fabrication of various kind. And therefore it addresses questions to the phase transition phenomena at low-scale and its limitations and control. In this report, we studied the crystal structure of tapered plates of Ti$_2$NiCu alloy and the temperature $T_c$ at which the martensitic transition occurs. We demonstrated that $T_c$ has a strongly descending character as a function of the plate thickness $h$. The critical thickness value at which the transition completely suppressed is 20 nm. Moreover, the obtained results for $T_c(h)$ curves indicate the hysteretic nature of the transition. These findings open the pathway for size limits indication and regimes modulation where the alloy-based nano-mechanical devices can be tuned to operate more efficiently.