Increasing the recycled contents is key to improve the sustainability of aluminium wrought alloys. Al scrap is often contaminated with Fe. Thus, coping with elevated Fe contents of wrought alloys is essential. However, more Fe leads to more intermetallic phases, which impact extrudability and Peripheral Coarse Grain (PCG) formation. Coarse grains at the surfaces of aluminium extrudates can have a major detrimental influence on ductility, corrosion, and fatigue behaviour. Therefore, it is desired to minimize the formation of PCG while keeping up the productivity of the process. PCG formation is dependent on local state variables such as temperature, strain, and strain rate, and second phase particles.

In this work, we study extrusion of alloys 6060, 6005A and 6082 with standard and increased Fe contents (0.2 and 0.7 wt. %). Design of experiment extrusion simulations were performed using the commercial extrusion software Inspire Extrude Metal. Ram speed, billet temperature, and tooling temperature were varied, for a total of 245 simulations for each alloy.

In order to tackle the large number of simulations, the evolution of microstructure was calculated after the extrusion simulation. For this purpose, the local state variables: temperature, strain, and strain rate, were taken from a plane cut of the profile. These parameters along with experimentally determined microstructure properties were used as input for a stand-alone microstructure simulation code.

The calculation of the microstructure evolution alongside the mean dislocation density-based flow stress increases the overall calculation performance. The output of the microstructure simulations were the final grain size distributions, which were compared to the microstructures obtained after extrusion experiments.

Our work furthers the understanding of the relationships between alloy composition, varying Fe levels introduced by recycling, process parameters, and PCG formation.