Effect of annealing parameters on the shape memory properties of NiTi thin films

Abstract

Sputter deposition was used to deposit amorphous, 1µm thick, Ti-rich NiTi films on silicon substrates which were annealed at various times and temperatures to alter their microstructure. The effects of heat treatments on the shape memory and mechanical properties of the films were analysed through temperature dependent x-ray diffraction and nanoindentation. These heat treatments were shown to affect the transformation temperatures, recovery ratios and hardness of the films and can be used as groundwork for designing laser processes for the fabrication of functionally graded shape memory devices.Sputter deposition was used to deposit amorphous, 1µm thick, Ti-rich NiTi films on silicon substrates which were annealed at various times and temperatures to alter their microstructure. The effects of heat treatments on the shape memory and mechanical properties of the films were analysed through temperature dependent x-ray diffraction and nanoindentation. These heat treatments were shown to affect the transformation temperatures, recovery ratios and hardness of the films and can be used as groundwork for designing laser processes for the fabrication of functionally graded shape memory devices.