This work concerns the novel Metal Continuous Screw Extrusion process (MCSE). The process gives new opportunities for processing metal alloys, composites and novel multi-materials. By principle, one ...feeds granulated material into the screw extruder which compacts and extrudes the material in a continuous manner. The inherent deformation is very complex and based on empirical knowledge, a comprehensive quantitative model for the strain evolution through the main four stages of the process is formulated for the first time.Data from screw extrusion of an Al-5%Mg alloy using an extrusion die temperature of 410 °C and relatively low feeding rate, showed a total accumulated strain ∼15 in the current prototype set-up for a Ø10 mm profile. Granule feeding rate and screw rotation speed are considered the most influencing parameters regarding predicted accumulated strain. The latter increases with lower feeding rates and higher rotation speeds of the screw. Further design optimization of the screw extruder might be assisted by the current model.
A novel method of screw extrusion was used for producing a bimetal composite Al/Mg from granules containing aluminium alloy 6063 (AA6063) and commercial pure magnesium. Up to 12.5% (mass fraction) ...pure magnesium was added to the aluminium alloy. In general, the material consisted of a fine grained microstructure. In addition to the phases originating from the input materials, intermetallic phases were observed as islands consisting of the Al2Mg3 phase surrounded by γ-Mg17Al12, throughout the microstructure. The mechanical properties of the extruded material showed a gradual increase in strength with increasing the addition of Mg. The highest registered UTS, well above 350 MPa, was observed for the material containing 10% Mg. Examinations of the fracture surfaces indicated that increasing the magnesium content led to a higher degree of brittle fracture and a gradual change of the fracture micro-mechanisms. The optimization of the post-extrusion processing conditions is still ongoing.
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