Nanoscale indentation behavior of pseudo-elastic Ti–Ni thin films

48.28 at.%Ti–51.72 at.%Ni thin films were prepared by magnetron sputtering and post-annealed at 450, 500, 550 and 600 °C, respectively. The evolution of structure, phase transformation and nanoscale indentation behavior of Ti–Ni thin film annealed at different temperature were investigated by X-ray diffractometer (XRD), differential scanning calorimetry (DSC) and nanoindention test, respectively. The results showed that the as-deposited Ti–Ni thin films were amorphous and crystallized after post-annealing. As the annealing temperature increased from 450 to 600 °C, both the content of parent phase (B2) and that of the precipitate phase (Ni4Ti3) increased. Both the phase transformation temperature and the micro-hardness of the annealed Ti–Ni thin films increased as well. Meanwhile, the pseudo-elasticity energy recovery ratio η first increased to the maximum value and then decreased with the increasing annealing temperature. It revealed that the annealed Ti–Ni thin film specimens exhibited the highest pseudo-elasticity degree with the largest η values under the load of 10 mN.