Influence of annealing on mechanical properties of TiNi (55.8 mass % of Ni) wire made for medical purposes

Mechanical properties of titanium nickelide processed with various heat treatments are investigated. Fractographic, microstructural and X-ray diffraction analysis' were carried out as well as strength and plasticity measurements. It is shown that titanium nickelide (55.8 mass % of Ni) wires treated by two annealing stages, which consist of heating up to 300°C on the first stage and 450°C on the second, with 4 hours and 15 minutes long exposures on each stage respectively, conducted in an air environment, possess the best strength while saving good elasticity figures. (paper)