| Abstract Scope |
One of the ways materials science is adapting to the climate crisis is by converting metal scrap streams into value streams, which increases material availability and decreases emissions. Aluminum is highly recyclable and versatile, though not all aluminum scrap streams are readily convertible into value streams due to the accumulation of certain elements that reduce recyclability. Opportunities exist to design new aluminum wire feedstocks for welding and additive manufacturing that can accommodate high concentrations of undesirable elements. To design an alloy derived from the scrap stream that is suitable for welding and additive manufacturing applications, evaluation of solidification cracking susceptibility, phase evolution, age hardening response, and fluidity must be considered. The Kou cracking susceptibility index was used to determine the composition space of the aluminum scrap stream that would be the least prone to solidification cracking. Representative compositions were then produced in the form of powder-core tubular wire feedstock. Manual gas tungsten arc welding (GTAW) was used to make wall-shaped builds free of solidification cracking. The builds were examined via X-ray diffraction and energy-dispersive X-ray spectroscopy to determine phase presence and morphology to compare against Scheil solidification model predictions. Additionally, the hardness of the alloy was measured before and after solution and aging experiments. It was found that after solution heat treating and peak aging, the hardness was comparable to 6061, which is notorious for solidification cracking. Further experimentation to evaluate the influence of Cu, Si, and Mg on the solidification cracking susceptibility and fluidity will be described. The results of this work show that the design of feedstocks for welding and additive manufacturing with sustainability as a primary objective is possible and can be applied to other material systems. |