The Spatial Variation of Crystallographic Texture During Axisymmetric Solid Bar Extrusion of an Al–Mg–Si Alloy

The use of aluminum extrusions in automotive applications is increasing to reduce vehicle weight for conventional internal combustion engine powered vehicles and more recently for battery electric vehicles. The mechanical response of the extruded material is influenced by microstructure and in particular, crystallographic texture. In this study, the variation of texture through the profile was examined by a combination of experimental extrusion trials conducted at near industry conditions and combined finite element method/polycrystal plasticity simulations. By the use of a special low-temperature homogenization treatment, recrystallization was suppressed to a large degree during and after extrusion. Further, the extrusion was stopped midpoint, and the die and the aluminum within it were quenched in order to study the flow of the material and its associated texture evolution in the die. It was found that the FEM/polycrystal plasticity simulations were in good agreement with experiments for material following streamlines which exit at 0 to 75 pct of the extrudate radius. Beyond 75 pct of the radius, the deformation conditions deviate strongly from ideal axisymmetric stretching and the possible intervention of alternative processes such as recrystallization or non-octahedral slip restrict the ability of the simulations to predict texture.