Dislocation density-based finite element analysis of large strain deformation behavior of copper under high-pressure torsion

Abstract

The paper is concerned with large strain deformation behavior of metallic materials as exemplified by copper under high-pressure torsion (HPT). To that end, the evolution of microstructure was considered in terms of a dislocation density-based constitutive model embedded in a finite element code. The variation of the specimen geometry, the hydrostatic pressure state, the equivalent strain and the dislocation density were examined by numerical simulations. The concurrent variation of the average dislocation cell size, which was identified with the emerging new grain size of the material, was also traced. The simulated results for the dislocation density and the grain size were shown to be in good agreement with the experimental data for commercial purity copper. It was concluded that the dislocation density-based constitutive model is well placed as a tool for describing and predicting the evolution of microstructure during severe plastic deformation, particularly HPT, using the finite element method. (C) 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.