Micromechanical modeling of ferritic/pearlitic steels

A two-dimensional micromechanical model based on the Voronoi algorithm is presented to model two-phase ferritic/pearlitic steels. Special care is taken to generate periodic grain structures as well as periodic finite element meshes. The model is evaluated by generalized plane strain finite element calculations, periodic representative cells are generated with the desired volume fraction pearlite. Loading by an arbitrary combination of average stresses or strains is possible by application of periodic boundary conditions. Uniaxial tension tests are performed on pure ferrite and pearlite specimens, as well as on materials containing 25 and 58% pearlite. Modeling of the two-phase materials was performed by using the stress–strain curves of the pure phases, in the description of the plastic properties. Comparisons between generated data and experiments at a loading strain of 2% show good agreement. Moreover, local stresses and strains are studied within the different unit cells. In addition, the model is used to investigate the plastic behavior under biaxial loading. It is shown that Hillʹs yield criterion gives a good fit to the numerical data.