Influence of recrystallization and subsequent aging treatment on superelastic behavior and martensitic transformation of Ni50.9Ti wires

In the present study, influence of different stages of recrystallization process and subsequent aging treatment on the superelastic properties of Ni-rich NiTi shape memory wires is investigated. Characteristics of transformation temperatures were determined using differential scanning calorimetry. Results indicate that annihilation of cold work effects after annealing results in changes on the features of DSC curves. The amount of residual strain is higher in the samples with cold work value of ε = 0.6 compared to the samples with ε = 0.4. The combination of annealing and aging treatment leads to improve in the superelastic properties. Results showed that different stages of the recrystallization process would affect the precipitation process in subsequent aging treatment.