Crystal plasticity prediction of texture evolution during helical extrusion process of aluminium alloys under three-dimensional deformation path

Abstract

Accurate prediction of the texture evolution of aluminium alloys during hot extrusion process plays an important role in the die design and determination of process parameters. In this work, the deformation textures of aluminium alloys under three-dimensional deformation path are investigated numerically and experimentally. Firstly, the extrusion process of a helical profile is simulated with HyperXtrude and the deformation history under three-dimensional deformation path of the profile is extracted. Then the deformation modes in the different positions on the profile are analyzed and the velocity gradients are imported respectively into FC-Taylor, ALAMEL and ALAMEL III models to predict the extrusion deformation textures. Finally, a specially-designed helical extrusion die is manufactured and the extrusion experiment are carried out. The textures are analyzed by EBSD to verify the predicted results by three crystal plasticity models. The results show that there are significant differences in the deformation modes from the centre to surface of the extruded profile and the three crystal plasticity models differ greatly in the prediction accuracy of textures. For the deformation texture of the helical profile, the FC-Taylor model gives better prediction at the centre position and the ALAMEL-type model predicts better at the surface position of the profile.