Novel Distortional Anisotropic Hardening Model Mediated by Microstructure Evolutions in Polycrystalline Metals: Theory and Validation

Abstract

In this study, we introduce a novel anisotropic hardening model designed to capture the macroscopic mechanical responses under complex loading paths while considering the mesoscopic evolutions of crystallographic structures. Based on the framework of homogeneous distortional anisotropic hardening, this model treats the plastic shear strain of each slip system as an internal variable. Utilizing the plastic work equivalence principle, the plastic shear rate within the slip system is determined, aligning with the evolution laws of rate-independent crystal plasticity (CP) theory. The model evaluates the Bauschinger effect and transient hardening at grain level and integrates it into the macroscopic yield function to describe phenomenological hardening responses. The model has been extensively validated against experimental and computational polycrystalline CP approaches, demonstrating its efficacy in capturing both the evolution of crystal textures and complex anisotropic hardening behaviors for both FCC and BCC materials. This proposed hardening model marks a significant advancement in material behavior modeling, effectively bridging the gap between microstructural mechanisms and macroscopic mechanical behavior in better practical way.

Keywords: Distortional hardening, Bauschinger effect, Anisotropic hardening, Crystal Plasticity, Texture evolution