Optimisation of processing and properties of medical grade Nitinol wire

The purpose of this paper is to review the current processing and resultant properties of standard Nitinol wire for guide-wire applications. Optimised Ti-50.8at%Ni wire was manufactured according to industry standards by prec ise control of the composition, cold work and continuous strain-age anneali ng. Mechanical properties of this wire are reported from -100 degrees C to 200 degrees C to demonstrate the effects of test temperature. Within the 's uperelastic window' the plateau stresses are linearly related to test tempe rature. Additional ageing treatments can be used as a tool to fine-tune tra nsformation temperatures and mechanical properties. A review of the fatigue properties of thermomechanically-treated Nitinol wire shows that they are affected by test temperature, stress and strain.