Three-dimensional numerical simulations of multi-pass equal-channel angular pressing by a variation difference method and comparison with experiment

摘要

A variation-difference method (VDM) of solving continuum mechanics equations has been implemented for simulation of the equal-channel angular pressing (ECAP) process. Application of the developed DRAKON code (VNIIEF, Russia) for numerical study of multi-pass ECAP allowed processes of severe plastic deformation to be described in three-dimensional (3D) continuum approximation in the field of low strain rates and high-pressure levels in terms of contact interaction. The influence of ECAP processing parameters on stress-strain field distribution over the ECAP sample's cross-section is studied in 3D formulation. The model validation is performed by comparison of simulation results with various experimental data. Deformation histories provided by DRAKON were used together with a polycrystal plasticity model (viscoplastic self-consistent model) allowing simulation of texture evolution during ECAP with account to macro-parameters of the process. It is shown that the VDM-based model possesses good predictive capabilities for 3D simulation of severe plastic deformation processes involving strain-path changes.