Screw extrusion-plasticizing friction stir deposition of 5183 Al alloy: Microstructure and mechanical properties

5xxx Al alloys are widely used in additive manufacturing (AM) components across various industries due to their advantageous properties, including low density, high strength, and excellent corrosion resistance. However, conventional melt-based AM methods often introduce defects such as pores, cracks and elemental evaporation. In the present study, a novel screw extrusion-plasticizing friction stir deposition (SEFSD) process, which enables the extrusion plasticization of 5183 particulate feedstocks via a three-stage tapered screw tool, was utilized to fabricate a 20-layer 5183 deposition wall through continuous linear reciprocating deposition in the solid state. The deposition wall exhibited a refined equiaxed microstructure. Due to the low stacking fault energy (SFE) of Al-Mg alloy, the influence of thermal cycles on microstructural evolution was minimal. Overall, the deposition wall demonstrated excellent mechanical properties, though strength and ductility in the deposition direction were reduced due to interlayer defects, which could be mitigated by incorporating stir pins or enhancing interlayer adhesive friction to intensify the material flow. This study confirms the applicability and significant potential of SEFSD for additive manufacturing 5xxx Al alloy components.