Influence of Increased Fe, Cu, and Zn Concentrations on Phase Formation in Aluminum A356 (AlSi7Mg0.3) Alloy

The production of Al alloysAl alloys from end-of-life (EoL) scrap is being accompanied by increased Fe-, Cu-, and Zn content. The influence of these elements was evaluated with special emphasis on phase formationPhase formation, via the application of CALPHAD methodsMethod to address the questions if a defined heat treatmentHeat treatment can compensate for the formationFormation of Al9Si2Fe2 and Al2Cu, how the combinations of such elements influence the formationFormation of detrimental phases and whether a combined approach of heat treatmentHeat treatment and alloy designAlloy design is valid for higher amounts of Fe, Cu, and Zn in primary-based alloysAlloys. It was found that Cu and Zn up to established limits in common supply specifications are less detrimental to alloyAlloys properties. Fe was found to be manageable, which is in good agreement with previous findings.