Analysis of texture evolution in equal channel angular extrusion of copper using a new flow field

Abstract

A new analytical model is presented using a flow line function to describe the material deformation during equal channel angular extrusion (ECAE) with a 90° die. The flow field is validated with finite element calculations of the ECAE. The new approach is compared to the classical discontinuous simple shear model of ECAE. The ideal orientations of ECAE textures are identified (and indexed) in accordance with the ideal orientations of simple shear textures, the shear being along the 45° intersection plane of the two channels. For testing the validity of the new flow line model, deformation texture developments were simulated using the viscoplastic Taylor and the viscoplastic self-consistent polycrystal plasticity models. By expressing the crystallographic textures in orientation space, detailed comparison with experiments have been done for the case of ECAE deformation of OFHC copper up to three passes following Route A. It is shown that the new model describes texture evolution better than the discontinuous shear approach.