Recycling Considerations for Wrought Aluminum Alloys Used in Light Vehicle Manufacturing

New applications for body structure and outer panels have increased the amount of aluminum sheet and extrusions used in automobiles and light truck manufacturing. While castings make up nearly 2/3 of the aluminum content in current vehicles, the growth of EV’s will drive the percentage of wrought (rolled and extruded) products to higher levels. 5xxx and 6xxx alloys make up the bulk of these wrought products, but the disparities in applications and chemical compositions pose problems for recycling in-process scrap and end-of-life vehicles. Forming, joining, and finishing all impose metallurgical limits on the choice of alloy for a given component. The chemical composition limits (Fe, Si, Mg, Mn, and Cr) and microstructures of the various sheet and extrusion alloys used in light vehicles are reviewed and the prospects for increasing their recycled content are considered. Issues of scrap mixing with other 5xxx or 6xxx alloy streams (cans, rod and bar, or forged wheels) are described.