Elucidating the role of combined latent hardening due to slip-slip and slip-twin interaction for modeling the evolution of crystallographic texture in high nitrogen steels

Abstract

A thorough framework for addressing the evolution of crystallographic texture in high nitrogen steels is developed in the present work. The elementary doctrine of the proposed framework is the inclusion of latent hardening due to slip-slip interaction along with slip-twin interaction in the visco-plastic self-consistent (VPSC) model for simulating the evolution of crystallographic texture in high nitrogen steels. The latent hardening due to slip-slip interaction is accounted for by specifying the complete interaction matrix (12 × 12), which allows all possible interactions between different slip systems. The latent hardening due to slip-slip interaction acts in combination with the latent hardening due to slip-twin interaction in raising the deformation resistance of the slip systems, which in turn enhances the propensity of twinning for the orientations along the β-fiber between the ideal Copper and S position. As a result, these β-fiber orientations are destabilized and reorient towards the $\alpha$-fiber orientations in the Euler space. The proposed modeling framework is validated against experimental orientation distribution function sections after different rolling reductions. It was observed that inclusion of the combined latent hardening effect provides a superior agreement with the experimental textures compared to the standard approach of considering only the latent hardening due to slip-twin interaction in low stacking fault energy materials. The modeling work is aptly supported by detailed microstructural characterization involving estimation of twin fraction via X-ray line profile analysis, twin characteristics via transmission electron microscopy and the reorientation caused due to twinning via electron back scatter diffraction.