A Proposition of a Kinetics Model for Stress-induced Martensitic Transformation in Fe-28Mn-6Si-5Cr Shape Memory Alloy

Shape memory alloys (SMAs) have been widely-used for many applications because of its unique characteristic. Among various kinds of SMAs, an Fe-based alloy indicates the excellent formability, machinability and weldability. In addition, its production cost is lower than other alloys. Therefore, it is attempted that the alloy is applied to structural members such as the joint and dampers. When the Fe-based alloy is used as the members, a model of the transformation kinetics with higher precision is indispensable to simulate the deformation behavior of the members for its design. In the past, the model of forward and reverse transformation kinetics has been proposed; however, the small initial value for the volume fraction of martensite must be introduced. In this study, the precise model for transformation kinetics will be derived from an idea of a nucleation site and the transformation probability based on thermodynamics. Then, a validity of the proposed model is confirmed by a comparison with the past-proposed model. As a result, the proposed model can express the result calculated by the model proposed in the past. Additionally, it is successful that weak points of the previous model can be improved.