PNNL

Abstract

Aluminum is publicly perceived as recyclable, but mixed alloys and impurities in aluminum scrap requires dilution via new energy-intensive primary aluminum or downcycling to low-quality castings. In this study, cast billets of shredded aluminum scrap (Twitch) were blended with pre-consumer AA 6061, extruded into tubes via Shear Assisted Processing and Extrusion (ShAPE), and aged to T1 and T6. Microscopy reveals that ShAPE refined and distributed the deleterious AlFeSi phases. The Twitch extrusions had tensile properties comparable to AA 6061 yet without homogenizing or adding primary aluminum. Energy and CO2 savings were 85% compared to conventional extrusion of primary aluminum alloys.