Ti53Ni47 shape memory alloy was annealed at different temperatures.Differential scanning calorimetry(DSC)was used to determine the phase transition point and study its phase transition behavior.Optical microscope(OM)was used to observe the microstructure.X ray diffractometer(XRD)was used for phase analysis.Hank's solution was used to simulate the humoral environment of human body curve was tested.The effects of heat treatment temperature on the microstructure and corrosion resistance were discussed.The results show that no phase transition occurs when the alloy is cooled or heated at-30-200℃.The alloy undergoes phase transition at 20-200℃.After high temperature annealing.The annealing temperature increases and the transition is easy.The room temperature phase of unannealed and 300℃annealed alloys is B2 phase,while the room temperature phase of the alloy annealed at 400℃and 500℃is B2 and B19'.There are black dots inside the alloy,its atomic fraction is approximately Ti51Ni49.After annealing,the corrosion resistance of the alloy in simulated body fluid environment is improved,but the nonlinear changes,showing a certain volatility.
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