The macro-and micromechanics of TRIP-assisted multiphase steels, experiments and modelling

摘要

This contribution describes selected results of an extensive experimental and modelling research program on the mechanical properties of TRIP-assisted multiphase steels. The elastoplastic behaviour of such complex microstructures presenting strain-induced phase transformation is indeed far from being completely understood and modelled. In order to determine the flow properties of each phase present in TRIP-aided steels, specific techniques have to be used. This work describes the mechanical characterisation of the properties of the different phases thanks to AFM-nanoindentation and neutron diffraction. The nanohardness of the phases as well as the influence of several parameters such as the chemical composition were measured. These results are in excellent agreement with the characterisation of the elastic and plastic behaviours of the same TRIP-aided steels carried out by neutron diffraction. Finally, modelling is used to provide insight into the micromechanics. A continuum constitutive model for multiphase materials is developed based on computational cell simulations. Emphasis is put on the comparison of the prediction of the model and experimental results.