Grain size estimations of annealed Ti–Ni shape memory thin films

Ti52.62Ni47.38 and Ti48.89N51.11 thin films were prepared by magnetron sputtering and post-annealed at 450, 500, 550 and 600 °C, respectively. Crystallization behavior and structure of Ti–Ni thin films were analyzed by differential scanning calorimetry (DSC) and X-ray diffraction (XRD), respectively. Line integral breadth method by XRD profiles was adopted to analyze the grain size and microstrains of annealed Ti52.62Ni47.38 and Ti48.89N51.11 thin films. The results showed that amorphous Ti52.62Ni47.38 and Ti48.89N51.11 thin films were crystallized at 460.5 and 490.8 °C with corresponding reaction enthalpy 14.8 and 20.6 J/g, respectively. As annealing temperature increased, crystallization degree and content of B2 and precipitate phases increased. Meanwhile grain size increased and microstrains decreased with increasing annealing temperature. Transmission electron microscopy (TEM) observation was made to confirm the feasibility of XRD analysis.