Abstract
The similar crystal structures of martensite (BCT) and ferrite (BCC) cause difficulty in distinguishing the grain orientations of individual phases in dual-phase (DP) steels. A dislocation-based multiphase mixed hardening model is presented, considering both ferrite and martensite strain partitioning, to describe the texture-dependent mechanical behavior of DP steels more precisely. This model is based on the ideals that (i) the volume fractions of the constituent phases and the corresponding strain partitioning function are obtained through in situ tensile experimentation, and (ii) the grain orientations of ferrite and martensite are assumed to be in accordance with the overall texture. We applied the model to calculate the macroscopic and microscopic mechanical behavior of DP800 steel using a crystal plasticity finite element (CPFE) code. The results show that the calculated stress-strain response and textural evolution are in good agreement with the experimental results. The dislocation evolution indicates that the rapid hardening of ferrite induces a high hardening rate for DP steels early in plastic deformation. In addition, for the grains corresponding to the texture center orientations of DP800, the activity and dislocation density evolutions of the slip systems are studied.
Highlights
The ever-increasing demands for lightweighting in manufacturing inspired increasing research on advanced high-strength steels (AHSS)
Based on the texture and the micro-strain partitioning function, the mechanical behavior of DP800 steel was predicted by crystal plasticity finite element method (CPFEM) using the new multiphase hardening law
◦, and 63◦ are shown the important figures of the orientation distribution function (ODF) at φ2 equal to CPFEM
Summary
The ever-increasing demands for lightweighting in manufacturing inspired increasing research on advanced high-strength steels (AHSS). Ogata et al [17] in 2017 analyzed the effects of different phase boundaries and microstructural evolution on the strain-hardening behavior by CPFEM They attributed the inhomogeneity of DP steels during secondary processing to the differences in deformability between martensite and ferrite. The existing literature suggests that these two phases can be treated as similar in texture [16,28,29] Considering these characteristics, this research examines the idea of superimposing the respective hardening effects of martensite and ferrite, and combining the strain partitioning function with the hardening law. Based on the texture and the micro-strain partitioning function, the mechanical behavior of DP800 steel was predicted by CPFEM using the new multiphase hardening law.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
