Recycling-Oriented Development and Microstructure–Property Evaluation of High-Recycled 6xxx Aluminum Alloys and CRM-Lean 6111 Alloy for Automotive Applications

Highlights: What are the main findings? MULTI-PICK–sorted aluminum scrap enables high melt cleanliness suitable for extrusion. Detailed OM, SEM/EDS, TEM, and EBSD analyses reveal that 6063 and 6082 alloys with high recycled content develop stable and uniform microstructures. The high-recycled 6063 and 6082 alloys, as well as the CRM-lean 6111 alloy, meet the mechanical requirements for automotive applications. What is the implication of the main finding? High post-consumer scrap content can be safely integrated into 6xxx aluminum alloys without compromising performance. Advanced sorting and controlled processing enable reliable industrial use of recycled aluminum for structural automotive components. The results support scalable, circular-economy aluminum production aligned with sustainability targets. Recycling of 6xxx aluminum alloys, which are used extensively in the automotive industry, is important for ensuring a carbon-neutral future and the efficient use of resources on Earth. The sustainability of recycling in aluminum alloys is directly proportional to the correct classification of the scrap to be used. In this study, scrap stream from a novel scrap-sorting technology called MULTI-PICK has been used to validate. The 6063 and 6082 alloys produced with scrap stream, which are commonly used for structural parts in the automotive sector, are analyzed with hydrogen analysis and PREFIL. Cast billets are evaluated considering extrusion. After extrusion, microstructures of the profiles are investigated with scanning electron microscopy (SE), transmission electron microscopy (TE) and electron backscatter diffraction (EBSD). Their mechanical properties and anisotropic behaviors are investigated with tensile testing in different orientations. Additionally, an alternative alloy called 6111 has been studied to replace the target alloys with low critical raw material (CRM) content. According to the findings, highly recycled 6xxx alloys can be used in the automotive industry without losing their existing properties. Furthermore, using alternative feedstock and retrofitted systems can decrease carbon footprint below 4 kgCeq/kgAl.