Effect of annealing temperature on surface morphology and mechanical properties of sputter-deposited Ti–Ni thin films

51.39 at.%Ti–48.61 at.%Ni thin films were prepared by magnetron sputtering and post-annealed at 450, 500, 550 and 600 °C, respectively. Crystallization kinetics of as-deposited Ti–Ni thin films was analyzed using differential scanning calorimetry (DSC). The evolution of structure, surface roughness and mechanical properties of Ti–Ni thin film annealed at different temperature were investigated by X-ray diffactometer (XRD), atomic force microscope (AFM) and nanoindention test. The results show that amorphous Ti–Ni thin films were crystallized at 506.3 °C with 18.6 J/g reaction enthalpy. As annealing temperature increased from 450 to 500 °C, crystallization degree of Ti–Ni thin film rose and surface roughness increased as well. As for Ti–Ni thin film annealed above 500 °C, Ti2Ni phase precipitated and surface roughness first increased and then decreased with increasing annealing temperature. Moreover, amorphous Ti–Ni thin films are softer than crystalline ones. Microhardness and Young's modulus of crystalline Ti–Ni thin films increased with increasing annealing temperature.