Influence of thermomechanical treatments on the behaviour of a shape memory NiTi alloy

Shape memory alloys are increasingly used in many fields where the particular properties of the initial shape recovery can be used for constructing components or actuators. In this case, it is fundamental to understand not only the mechanical properties but also the micro-structural behaviour and the related influences on the mechanical behaviour through the formulation of micromechanical models used in various control systems. In this work, the influence of thermomechanical treatments on the parameters of a micromechanical model able to predict the first three stages of the stress-strain curve of shape memory alloys, and to evaluate the trend of the microstructure variation in terms of austenite and martensite quantities during a tensile test, is presented. It was found that the considered heat treatments do not affect the elastic parameters of the material, but influenced the parameters associated with the variation of the microstructure.