Deformation field and texture analysis in friction-assisted lateral extrusion of aluminum

Abstract

A new flow line model was developed based on experimental observations to describe the deformation field and texture evolution in a novel severe plastic deformation (SPD) technique, named the Friction-Assisted Lateral Extrusion Process (FALEP). FALEP produces a sheet from bulk metal in one step. The microstructure and crystallographic texture of Al-1050 material after FALEP deformation were investigated by EBSD and XRD after an extrusion ratio of 10.5. Heterogeneity in the microstructure and texture was observed within the thickness of the sheet with average grain sizes of 720 nm and 4.2 μm near the top of the obtained sheet and the bottom, respectively. Flow lines were ascribed within split-samples before testing. They revealed large deviations from the expected simple shear model; three-stage deformation paths were observed. They consisted of two simple shear stages and a new linear convergent extrusion (‘LCE’) type of flow between them. An analytical flow line model was constructed for obtaining the deformation field for the LCE part of the flow. Texture simulations were carried out using the viscoplastic Taylor and the viscoplastic self-consistent models. The classical simple shear model was not able to properly reproduce the experimental textures. However, the new flow line model accurately described the texture evolution both at the top and bottom regions of the sheet. The obtained total strains were more than twice less than the one expected from the classical uniform simple shear deformation model.