A multi-scale model of martensitic transformation plasticity

The remarkable mechanical engineering properties of many advanced steels, e.g. TRIP steels and metastable austenitic stainless steels, are related to their complex microstructural behaviour, resulting from the interaction between plastic deformation of the phases and the austenite to martensite phase transformation during thermomechanical loading. In this paper, a multi-scale physically-based model is presented for the prediction of such structure–property relations for materials exhibiting the martensite phase transformation during mechanical loading. The model incorporates several spatial levels: a macroscopic or engineering level, a mesoscale level of a single austenite grain and a microscale level of smaller domains within the austenite grain where the martensitic transformation takes place on particular crystallographic transformation systems. The model directly incorporates the coupling between elastic and plastic deformation of the phases and the transformation, as well as the dependence of the transformation on the (hydrostatic) stress state, grain orientation with respect to the loading and the history of deformation and transformation. The performance of the model is evaluated on several examples, illustrating the ability of the model to predict the orientation and stress-state dependence of the transformation. The developed model can be used for the systematic study of structure–property relations of these inherently multi-scale materials.