PHASE-TRANSFORMATION BEHAVIOR AND MICROMECHANICAL PROPERTIES OF A DUAL-PHASE STEEL AFTER CHEMICAL MODIFICATIONS

In this work, the phase-transformation behavior and micromechanical properties of a dual-phase steel after chemical modifications were investigated theoretically and experimentally. In particular, the micromechanical behavior of the steel was modeled, based on the effects of the microstructure, phase fractions, local compositions of single phases and their area shapes. The developed model was used for predicting the damage behavior of a specimen. It was demonstrated that the tensile strength increased with the increasing temperature due to an increase in the amount of martensite in the steel, but the hardening behavior of this specimen was affected by the microstructure. Furthermore, the flow curves of the steel under different intercritical temperatures could be well predicted based on the real microstructures. The subsequent simulation results showed that while higher stress concentrated on the martensite, the shear-band appearance strongly depended on the microstructures of the phases. In addition, for the prediction of damage behaviors, the true stress/true strain curves of macroscale simulations showed good agreement with the experiments involving differently heat-treated steels.