Shape memory alloy (SMA) thin films, especially those based on Ni-Ti, have received considerable attention since it was demonstrated that they can undergo a nearly perfect shape memory effect [1-7]. When SMA films are used as actuators in MEMS devices, biasing springs are generally needed to restore the initial state in order to achieve a twoway shape memory effect. As a result, use of SMA actu...

The shape memory effect and superelasticity are usually found in alloys exhibiting spontaneous martensitic transformation. Thus it is hard to imagine that such interesting effects can appear in a system without a martensitic transformation. In this Letter we show shape memory and the superelasticity effect in a nonmartensitic Ti48.5Ni51.5 alloy, which has no martensitic transformation but under...

Shape memory alloys (SMAs) are a class of smart materials characterized by shape memory effect and pseudo-elastic behavior. They have the capability to retain their original form when subjected to certain stimuli, such as heat or a magnetic field. These unique properties have attracted many researchers to seek their application in various fields including transportation, aerospace, and biomedic...

Driven by the increasing demand for micro-/nano-technologies, stimuli-responsive shape memory materials at nanoscale have recently attracted great research interests. However, by reducing the size of conventional shape memory materials down to approximately nanometre range, the shape memory effect diminishes. Here, using density functional theory calculations, we report the discovery of a shape...

This work presents a three-dimensional constitutive model for shape memory alloys considering the TRansformation-Induced Plasticity (TRIP) as well Two-Way Shape Memory Effect (TWSME) through large deformation framework. The presented logarithmic strain based is able to capture strains and rotations exhibited by SMAs under general thermomechanical cycling. By using martensitic volume fraction, t...

The mechanical properties of sputter-deposited NiTi shape memory alloy thin films ranging in thickness from 35 nm to 10 μm were examined using nanoindentation and atomic force microscopy (AFM). Indents made in films as thin as 150 nm showed partial shape recovery upon heating, although film thickness was found to have a marked effect on the results. A modified spherical cavity model is used to ...