Heat treatment of TiNi wire used for intrauterine contraceptives

For years superplastic TiNi alloys have been used in many medical fields making use of their properties: superelasticity and biocompatibility. High corrosion resistance, biological inertness, plastic properties of TiNi allowed these alloys to be used as intrauterine contraceptives, significantly reducing complications in the insertion procedure and during use. This article is aimed at choosing the proper heat treatment of Ti–50.8 at.%Ni wire intended for intrauterine contraceptives. The effect of aging temperatures from 250 to 550 °C on the characteristic transformation temperatures, superelastic properties and shape setting has been studied. The optimal heat treatment conditions for shape setting and pseudoelastic properties in the operating temperature range have been determined.