3D printing of aluminum alloys under different extrusion techniques
(English) This doctoral research evaluated the feasibility of using various aluminum-based feedstocks in additive manufacturing (AM) to develop cost-effective and environmentally friendly alternatives to traditional metal fabrication. The study systematically examined AA6061 filament, AlSi10Mg granu...
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| Formato: | tesis doctoral |
| Estado: | Versión publicada |
| Fecha de publicación: | 2025 |
| País: | España |
| Recursos: | CBUC, CESCA |
| Repositorio: | TDR. Tesis Doctorales en Red |
| OAI Identifier: | oai:www.tdx.cat:10803/695825 |
| Acesso em linha: | http://hdl.handle.net/10803/695825 https://dx.doi.org/10.5821/dissertation-2117-446580 |
| Access Level: | acceso embargado |
| Palavra-chave: | FDM screw-based extrusion DIW thermal debinding sintering Àrees temàtiques de la UPC::Enginyeria dels materials 620 - Assaig de materials. Material comercials. Economia de l'energia |
| Resumo: | (English) This doctoral research evaluated the feasibility of using various aluminum-based feedstocks in additive manufacturing (AM) to develop cost-effective and environmentally friendly alternatives to traditional metal fabrication. The study systematically examined AA6061 filament, AlSi10Mg granules (commercial and recycled), and AlSi10Mg powder paste across three AM techniques: Fused Deposition Modeling (FDM), screw-based extrusion, and Direct Ink Writing (DIW). The main objectives were to optimize printing, thermal debinding, and sintering parameters for each feedstock and AM technique, and to assess the resulting mechanical properties and microstructures of the fabricated parts.For printing, AA6061 filament processed via FDM achieved optimal results with a 0.8 mm nozzle diameter at 205 °C. AlSi10Mg granules (commercial and recycled) and AlSi10Mg powder paste, used in screw-based extrusion and DIW respectively, performed best with 0.6 mm nozzles and lower temperatures. These optimizations established critical baseline conditions for subsequent processing steps, emphasizing the distinct requirements of each material and technique.Thermal debinding, essential for removing polymeric binders before sintering, was optimized for each feedstock. For AA6061 filament, 550 °C with holding times up to 3 hours was most effective. For commercial AlSi10Mg granules, 350 °C for 3 hours yielded optimal results, a condition that also worked for recycled granules and powder paste. These parameters minimized defects and prepared the parts for successful sintering.Sintering parameters were rigorously optimized to ensure densification and desired mechanical properties. AA6061 filament was best sintered at 635 °C, while commercial AlSi10Mg granules and powder paste achieved optimal results at 600 °C. Recycled AlSi10Mg granules reached peak performance at 620 °C. All sintering was conducted for 3 hours under a nitrogen atmosphere with vacuum and oxygen traps. SEM analysis confirmed increased densification and uniform microstructures under these conditions.A pre-sintering pressing technique was introduced to further enhance densification and reduce porosity. This step significantly improved the relative density of sintered parts by 19.25–45.55%, with pressed samples achieving densities up to 93.65%. Mechanical testing showed that recycled AlSi10Mg granules provided the highest compressive strength (168.34 MPa), followed by commercial granules, AA6061 filament, and powder paste. |
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