Mechanical Properties of Solid-State Recycled 4xxx Aluminum Alloy Chips

Abstract

The direct production of aluminum from bauxite ores is known to be a very energetic-intensive operation compared to other metallurgical processes. Due to energy issues and the rapid increase in aluminum demand, new kinds of aluminum production processes are required. Aluminum waste recycling, which has an advantage of lowering the cost of electric power consumption, is considered to be an alternative route for material manufacturing. In this work, the way of reusing aluminum EN-AC 44000 alloy scraps by hot extrusion was presented. Metal chips of different sizes and morphology were cold compacted into billet form and then hot extruded. Mechanical properties investigations combined with microstructure observations were performed. Mechanical anisotropy behavior of material was evaluated on the base of tensile test experiments performed on samples machined at 0°, 45°, and 90°, respectively, to the extrusion direction. It was found that the initial size of the chips has an influence on the mechanical properties of the received profiles. Samples produced from fine chips revealed higher tensile strength in comparison to larger chips, which can be attributed to a refined microstructure containing fine, hard Si particles and Fe-rich intermetallic phases. Finally, it was found that anisotropic behavior of chip-based profiles is similar to conventionally cast and extruded materials which prove good bonding quality between chips.

Analysis of Microstructure and Mechanical Properties of AlSi11 after Chip Recycling, Co-Extrusion, and Arc Welding

“…The tests of materials after hot co-extruding have shown that, regardless of the size of the chips used, it is possible to obtain good mechanical properties, i.e., YS > 120 MPa, UTS = 167 Mpa, and A > 11%. The obtained results are consistent with the values [ 32 ]. This shows that the recycling method used for production allows for obtaining a full-value base material.…”

“…On the other hand, the fracture is quasi-ductile, with visible traces of plastic deformation, and the β-phase plates are visible on the fracture surface. The analysis of the alloying elements concentrations showed that these precipitates are rich in silicon (α+Si eutectic, β-Si phase) and other elements, mainly Fe and Mn (e.g., AlSiFeMn intermetallic phase) [ 32 ]. The secretions are small and located in the interdendritic regions.…”

Effect of Various Forms of Aluminum 6082 on the Mechanical Properties, Microstructure and Surface Modification of the Profile after Extrusion Process

“…The highest elongation values of 15% were obtained for the material made of fine chips; the material obtained from a solid ingot and coarse chips slightly deviated from the material made of fine chips and reached elongation of 13.8% and 14.2%, respectively. For comparison, Krolo et al, testing the same alloy, obtained UTS values of 150 MPa for consolidated shredded forms at the process temperature of 400 • C [47], while Tokarski, conducting similar tests, obtained UTS equal to 160 MPa [48]. Reduced strength properties of profiles after plastic consolidation as compared to solid material may be caused by the presence of oxygen layers on the chip surface, which was confirmed by the authors in [49].…”

Effect of Thermally Formed Alumina on Density of AlMgSi Alloys Extrudate Recycled Via Solid State Technique

“…In recent years, there has been an increasing trend in research works that are focused on the issue related to sustainable manufacturing. The study includes recycling of aluminium chips using a solid-state technique, in which the process is performed in a melt less process [1][2][3][4][5]. The process used 95 % less energy than the conventional technique [6], which conserve natural resources and a safe environment due to less greenhouse gas emission.…”