Aluminium Alloy Powders Production From Compacted Chips: Process Optimization and Powder Characterization

The manufacturing sector faces increasing pressure to improve environmental sustainability due to its high energy and resource demands. Key strategies include waste reduction and scrap material recycling. Powder-based additive manufacturing (AM) is inherently more resource-efficient than traditional methods, primarily due to lower material losses. However, its sustainability must be assessed across the full material lifecycle. In particular, gas-atomized metal powder production—the main feedstock for AM—is energy-intensive and heavily reliant on virgin materials. This thesis investigates the recycling of AA5183 and AA4047 aluminium alloy chips, generated during rod peeling prior to cold drawing in welding wire production. The chips were compacted and gas atomized with argon using a Vacuum Inert Gas Atomizer (VIGA) in a close-coupled configuration. The primary objective is to demonstrate the feasibility of producing powders from industrial scrap with properties comparable to commercial powders (AA5083 and AlSi10Mg) used in Laser Powder Bed Fusion (LPBF). Characterization methods included particle size analysis (laser diffraction), true and bulk density measurements, morphological and rheological testing, SEM and optical imaging, and energy-dispersive X-ray spectroscopy (EDS). A secondary aim was to maximize atomization yield by varying the melting temperature: 850°C and 1000°C for AA5183, and 850°C and 880°C for AA4047. Results show that the recycled powders exhibit similar porosity and flowability to their commercial counterparts, indicating suitability for LPBF. An estimation of the embedded CO₂ contribution from a single atomization cycle was evaluated to assess the environmental impact of the recycling process.