Optimization of the chemical composition of a commercial AA6060 alloy to maximize extrudability and mechanical properties

A new AA6060 alloy composition was proposed modifying a standard composition in which the Mg and Si contents were reduced to the minimum level allowed, with the aim to increase the alloy extrudability and reduce the extrusion time. With the novel composition extruded Al profiles were manufactured, from which tensile test samples were cut. Applying a proper ageing cycle, mechanical properties higher than the minimum values required for this alloy were achieved, also in the case of the minimum Mg + Si content. A significant improvement in extrudability was observed reducing the amounts of Mg and Si. The low content of these alloying elements led to a consistent increase in the extrusion velocity exploitable without the occurrence of any surface defect. A temperature model has been formulated to describe the appearance of defects on the surface of the extruded profiles like die lines and pick-ups.