Origin of transformation hysteresis expansion by deformation of shape memory alloys

Recent experimental investigations have demonstrated that the pre-deformation of shape memory alloys results in martensite stabilization opposing reverse transformation, hence leading to the expansion of transformation hysteresis. Here a kinetic study has been made in order to determine the relationship between the relaxation of elastic energy and the hysteresis expansion by pre-deformation of shape memory alloys. It is indicated that the relaxation of elastic energy stored during the forward martensitic transformation is responsible for the expansion of transformation hysteresis, which is in good agreement with experimental results associated with the hysteresis enlargement by deformation of NiTi, NiTi-based and CuAlNi shape memory alloys.