In Situ Experimental Study of the Nucleation and Growth of Fe-Al Based Intermetallics: An Insight for Designing Next-Generation Recycling Friendly Aluminium Alloys

Today’s focus in the aluminiumAluminium industry is promoting a circular economyCircular economy, thus meeting the US and the EU's ambition of reducing greenhouse gasGreenhouse gases emissions. This means replacing primary aluminiumPrimary aluminium with post-consumer scrap, which contains larger quantities of intermetallicIntermetallics forming impurities, particularly Fe and Si, which are detrimental to mechanical propertiesMechanical properties. We need to develop new generations of impurity-tolerant aluminium alloysAluminium alloys enabling reduced carbon footprintCarbon footprint through increased recycled content. To meet this objective, it is necessary to deepen our understanding of AlFeSi secondary phase nucleation and growth during aluminium alloyAluminium alloys solidificationSolidification. In this work, model 6xxx6xxx recyclingRecycling-friendly alloysAlloys were manufactured and unique in situ directional solidificationDirectional solidification experiments were performed. For the first time, nucleation and growth of α-AlFeSi and β-AlFeSi intermetallicsIntermetallics were observed in real time in thin samples of model 6xxx6xxx alloysAlloys. We discuss the effect of chemistry modificationModification and solidificationSolidification parameters on the AlFeSi phase nucleation and growth.