a simple model to calculate the microstructure evolution in a niti sma

Shape memory alloys (SMAs) are a wide class of materials characterized by the property to recover the initial shape. This property is due to ability of alloys to change the microstructure from a �parent� microstructure (usually called �Austenite�) to a �product� microstructure (usually called �Martensite�). Considering the tensile resistance, SMAs stress strain curves are characterized by a sort of plateau were the transformations from Austenite to Martensite (in loading condition) and from Martensite to Austenite (in unloading condition) take place. In this work a simple model to predict the microstructure modification has been proposed and verified with an equiatomic NiTi alloy characterized by a pseudo-elastic behavior