Evaluating the use of scrap metal to produce Al-5Cu-3Ti-1Cr-1Fe alloy powder for laser powder bed fusion

This study compares the production of Al-5Cu-3Ti-1Cr-1Fe alloy powders for laser powder bed fusion (PBF-LB/M) using either virgin or recycled and scrap materials as feedstock. As for the latter, three different material sources, namely aluminum 2024, Ti-6Al-4V and AISI 316L, were selected to reproduce the target alloy composition by gas atomization. The feasibility of achieving high-quality alloyed powder from mixed scrap sources was demonstrated, with particular focus on processability, mechanical performance, and environmental impact. Both powders produced from scrap/recycled (Re-Alloy) and virgin (V-Alloy) feedstock materials were processed via PBF-LB/M to compare their printability, and the manufactured samples were tested to evaluate their mechanical properties. The Re-Alloy exhibited a stable PBF-LB/M processability over a wide set of parameters, attributed to the presence of elements like Si and Mg, which improved laser absorptivity. Mechanical testing revealed comparable properties, with the Re-Alloy achieving slightly lower strength but higher elongation at break due to the reduced Fe content. Finally, a life cycle assessment (LCA) analysis quantified the environmental impacts, showing a significant reduction of approximately 50% in the carbon footprint for the Re-Alloy powders (15.5 +/- 1.0 kgCO2/kg) compared to the V-Alloy (31.5 +/- 1.8 kgCO2/kg). The carbon footprint of the PBF-LB/M process itself was measured at 15.2 +/- 1.2 kgCO2/kg of deposited material. This research highlights the potential of using recycled and waste materials to reduce the environmental impact of metal powder production while maintaining technical feasibility. The findings offer a promising approach for enhancing the sustainability of additive manufacturing processes.