## 3 Results and Discussion  
### Microscopy Analysis  
Figure 4 shows the macrostructures for all six specimens obtained with different welding procedures. It seems that the appropriate selection of welding parameters was crucial to avoid significant delamination and porosity in the welded specimens. For both MIG-welded specimens (recycled and conventional), some microporosity is visible. Because of the round-shaped porosity, it is likely gas porosity (Figure 4a,d). This indicates that the specimen's welding procedure can be further optimized; however, there is no significant \begin{table}
\begin{tabular}{c c c c} \hline
**Welding Process/** & **MIG** & **TIG (One Side)** & **TIG (Two Sides)** \\
**Parameter** & & & \\ \hline
**Electric current (A)** & 175 & 120/80 & 110/70 \\
**Work mode** & DCEP & AC & AC \\
**Pulse welding** & No & Yes (50/50) & Yes (50/50) \\
**Protective gas** & Argon 100\% & Argon 100\% & Argon 100\% \\
**Gas flow (L/min)** & 20 & 10 & 10 \\
**Electrode type** & \(\phi\) 1.2 mm aluminum & \(\phi\) 2.4 mm tungsten & \(\phi\) 2.4 mm tungsten \\
**Filler material** & AlMg\({}_{5}\) (5356) & AlMg\({}_{5}\) (5356) & AlMg\({}_{5}\) (5356) \\
**Moving speed (cm/min)** & 53.57 & \(\approx\)20 & \(\approx\)30 \\
**CTDW (mm)** & 20 & - & - \\ \hline \end{tabular}
\end{table} 
Table 2: Parameters for welding the 4 mm thick EN AW 6082 aluminum alloy sheets. Figure 3: Tensile test specimens: (**a**) dimensions; (**b**) welded conventional and SSR specimens after tensile testing. difference in the appearances of the welded SSR and conventional specimens. This indicates that, despite the residual aluminum oxide concentrations in the SSR specimens from the surface of the machining chips, there is still the possibility of performing semi-automatized MIG welding without any significant errors. This is addressed and confirmed in this paper in the following investigation of the mechanical properties. For the specimens welded with the TIG process on one side, there was some porosity visible in the SSR specimen; however, in the conventional specimen there was no porosity (Figure 4b,e). However, the appearance of different fusion zones indicates that at this specific point the welding conditions were somewhat different, which is expected because it was hand-welded by a welder. Overall, both TIG-welded specimens had good overall appearances without any significant delamination or cracks, which indicates that the SSR and conventional specimens were similarly welded. For the two-sided TIG-welded specimens, a few interesting observations are noted in Figure 4c,f. Firstly, for the TIG SSR specimen, some delamination in the HAZ occurred (Figure 4c). This could be caused by overheating but is more likely due to the low extrusion ratio during the solid-state recycling; a low bonding chip area was revealed during etching. The macroscopy analysis results indicate that a higher extrusion ratio or rolling reduction should be used to prevent possible delamination during the welding of SSR specimens. [PERSON] et al. [21] proved that, although micrographs of chip-based extruded profiles did not show delamination between individual chips, it was found that there was a critical diameter where the combination of the necessary properties of high strain and pressure was considered too low to lead to sufficient chip bonding, resulting in crack initiation and delamination during fatigue testing. The chip bonding quality, without a doubt, will interfere with the mechanical properties, as shown in previous research. Therefore, analogously, the chip bonding quality will have a significant impact on the solid-state-recycled specimens after processing (e.g., welding). According to [PERSON] et al., the use of an extrusion ratio lower or equal to 17 will lead to delamination, and, therefore, a higher extrusion ratio should be applied for flat-face dies to prevent the aforementioned [15].