Modeling of Lüders Elongation and Work Hardening Behaviors of Ferrite-Pearlite Dual Phase Steels under Tension

Because of their good combination of strength and ductility, ferrite-pearlite (F-P) dual phase steels are widely used as structural components for various engineering applications. Several numerical models have been developed to predict the flow behavior of F-P steels with a focus on the strain hardening effect. However, little attention has been put on modeling the Lüders elongation phenomenon, which dominates the plastic behavior of F-P steels at a relatively low-strain range. This research is to establish a stress-strain model capable of predicting both the Lüders elongation and work hardening behaviors of F-P steels subjected to room temperature tension. Representative volume element method in combination with finite element simulation is used for the overall stress-strain relationship prediction. The effects of ferrite grain size, pearlite volume fraction, and pearlite inter-lamellar spacing on flow behaviors are investigated. Model validation is achieved by comparing the simulation results with experimental data from literature.