Comparison of experimental AA6063 extrusion trials to 3D numerical simulations, using a general solute-dependent constitutive model

In this paper, laboratory scale extrusion experiments carried out on AA6063 billets are compared to numerical simulations. The numerical simulations are performed with a general solute-dependent elasto-viscoplastic constitutive model based on a hyperbolic sine law, allowing for the quantification of pressure levels, strain rates and stresses. The parameters for the material model were determined with compression tests. The extrusion trials were performed isothermally at temperatures of 623 and 723 K and with two distinct material conditions. The results of the numerical simulations show good agreement with the experimental results. It turns out that local high strain rates (>40 s−1) have a significant influence on the extrusion pressure. However adequate test methods to provide constitutive data at these strain rates are very limited. At high temperatures the difference between material conditions had a considerably smaller influence on the extrusion experiments compared to the simulations. It is argued that this effect can be attributed to dynamic precipitation that occurred during the experiments under high temperature, high strain rate conditions.