PNNL

Abstract

Shear Assisted Processing and Extrusion (ShAPE) was developed to manufacture non-circular multicell profiles from secondary aluminum. This was accomplished by integrating a porthole die approach within the rotating ShAPE process. Complexity of the profile geometry was deliberately advanced over the course of the project from round to square, to asymmetric trapezoidal, to two-cell asymmetric trapezoidal. Aluminum alloy 6063 in the form of briquettes (compacted shreddings and engineered machining chips) and castings from pre-consumer industrial scrap were utilized as the feedstock. Tensile properties were shown to exceed the ASTM minimum standard and ASM typical values with the best results reaching yield strength = 228 ± 8 MPa, ultimate tensile strength = 251 ± 7 MPa, and uniform elongation = 15.5 ± 1.2% for porthole extrusions directly from unhomogenized castings made from 100% aluminum 6063 industrial scrap. The ability to extrude unhomogenized billet was made possible by in situ conversion of plate-like ß-type Fe-rich intermetallics to more extrudable needle-like a-type which is not possible with conventional extrusion. By eliminating the need to dilute iron with primary aluminum during the recycling process, savings of >90% on lifecycle carbon footprint and >50% on embedded energy can be realized ultimately resulting in lower cost, more environmentally friendly, automotive components.