Modeling the mechanical response of a Dual-Phase steel based on individual-phase tensile properties.

In this work, the engineering stress–strain tensile curve and the force-deflection bending
curve of two Dual-Phase (DP) steels are modeled, combining the mechanical data of fully ferritic and
fully martensitic steels. The data is coupled by a modified law of mixture, which includes a partition
parameter q that takes into account the strength and strain distributions in both martensite and
ferrite phases. The resulting constitutive model is solved in the context of the finite element method
assuming a modified mixture rule in which a new parameter q0 is defined in order to extend the
capabilities of the model to deal with triaxial stresses and strains and thus achieve a good agreement
between experimental results and numerical predictions. The model results show that the martensite
only deforms elastically, while the ferrite deforms both elastically and plastically. Furthermore,
the partition factor q0 is found to strongly depend on the ferritic strain level. Finally, it is possible
to conclude that the maximum strength of the studied DP steels is moderately influenced by the
maximum strength of martensite.