## 3 Results and Discussion
### Mechanical Properties Analysis
The somewhat lower ultimate tensile strength results were expected because of the specific annealed thermal state of both the recycled and conventional base material sheets. For both MIG-welded specimens, fractures occurred in the heat-affected zone, which suggests that further softening of the material occurred (Figure 3). Furthermore, according to the results of the tensile tests of the specimens welded with TIG on the one side, there was a significant drop in the mechanical properties (Table 3). On the other hand, the microhardness measurements showed increased microhardness values compared with the MIG-welded specimens. This clearly indicates that the drop in the tensile testing results for the TIG-welded specimens was not due to the microstructural characteristics but to the incomplete fusion between the base materials and the filler material in the weld zone. The authors of this research attempted to obtain a visibly acceptable TIG weld with the lowest possible heat input to prevent delamination of the SSR specimens and development of porosity, as explained in Figure 2, but this led to a lack of interfusion, which is evident from the tensile testing results in Table 3. The lack of fusion and lack of penetration are the result of the low heat input from the low current applied [38; 39; 40]. For the specimens welded with TIG on two sides, despite a lower welding current and an incompletely filled groove, the tensile testing results for both ultimate tensile strength and elongation were twice as high compared with the TIG-welded specimens on one side (Table 3). This indicates and confirms that a better welding procedure and better fusion between the base material and filler material were necessary; however, the mechanical properties were still lower compared to the MIG-welded specimens due to the incompletely filled groove, as mentioned above. This is also why fracturing occurred in the middle of the weld material  
Figure 5: Microhardness distribution for both the solid-state-recycled and conventional specimens with different welding procedures: (**a**) measurement positions; (**b**) MIG-welded; (**c**) TIG-welded on one side; (**d**) TIG-welded on both sides. during the tensile tests of the two-sided TIG-welded specimens, while for the one-sided TIG-welded specimens, fracturing occurred near the fusion zone (Figure 3). This also confirms the abovementioned conclusions. Incomplete joint penetration in welds can occur due to factors such as insufficient heat, rapid travel speed, improper joint design, incorrect level angle, or poor arc control. This discontinuity is particularly problematic in groove welds under cyclic tension, as it can initiate cracks leading to catastrophic failure. In welds made from one side, incomplete penetration can cause bending at the root, resulting in failure with minimal deformation. For joints welded from both sides, when incomplete joint penetration is present at the neutral axis, the bending stresses are lower, but they are concentrated at the ends of the discontinuity [41]. Therefore, it is fair to claim that the TIG welding parameters should be changed with a higher heat input. This can be achieved using a regular DC current, without pulsed mode, and increasing the overall welding current or reducing the welding speed. Also, different joint preparations with applied level angles could be used for better penetration. Overall, for all TIG-welded specimens, a somewhat lower ultimate tensile strength and higher elongation were observed for the welded SSR specimens compared to the conventional ones. As the main objective of this research was a comparative analysis of the welding behaviors of both conventional and solid-state-recycled EN AW 6082 alloy, in general, it is fair to claim that under similar welding conditions, similar mechanical properties were achieved, but similar welding errors and imperfections were also present.