Pulsed-laser deposition of TiNi shape memory alloy thin films

Abstract

Thin films of TiNi shape memory alloy (SMA) have been prepared by pulsed-laser deposition (PLD) at different substrate temperatures. The stoichiometry, crystallinity, and morphology of the deposited films were characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and atom force microscopy (AFM). The transformation behavior and crystallization temperatures were investigated by differential scanning calorimetry (DSC). It is found that the Ni content of the deposited films ranges from 46.7 to 52.0 at.%. The crystallization temperature of the amorphous films is around 460°C. The activation energy of the crystallization process is determined by Kissinger's method to be 301 kJ/mol. The martensitic transformation temperature of the annealed Ti-51.5 at.% Ni film is -20.8°C.