On the Fundamental Limits of the Size of the Shape Memory Nanoactuators Posed by Martensitic Transition in Ti2NiCu Shape Memory Alloy on Nano-Scale

The crystallographic structure of the wedge-shaped plates of the alloy Ti
₂
NiCu was studied by transmission electron microscopy (TEM) in the temperature range 100-400K. The results obtained show that as the plate thickness decreases the temperature at which the martensitic transition occurs decreases too with the transition comes to an end when the plate thickness reaches 20 nm. A plot showing the relationship between the extent of martensitic transition and plate thickness has been obtained, bringing to light the hysteretic character/nature of the transition. The fundamental limitations derived from the theoretical and experimental considerations confirm in principal submicron overall size of the robotic systems based on martensitic transition and shape memory effect.