## 3 Results and Discussion
### Mechanical Properties Analysis  
Figure 5 presents diagrams of the microhardness distribution along the welded specimens. Figure 5a shows the measuring positions on the welded specimens, and Figure 5b shows the microhardness distribution for both the SSR and conventional specimens after MIG welding. Because of the annealed characteristics of the specimens, the microhardness values were in a range from around 40 HV to 60 HV. The main aim of this research was to conduct a comparative analysis of the welded conventional and recycled specimens, and according to the measurements, quite similar behaviors were exhibited, with no significant drop in the hardness of the HAZs, fusion zones, or base materials. There was even an increase in the hardness near the HAZ and the transition zone between the base material and the fusion zone. Because of the high heat input during the welding and the annealed condition of the heat-treatable EN AW 6082 aluminum alloy, there is the possibility that some part of the material reached a solid solution temperature, which subsequently led to solid solution strengthening in that particular zone. According to Figure 5b, it is fair to claim that relatively similar microhardness distributions were achieved for both the SSR and conventional specimens. For other welding procedures, the same conclusion can be drawn; however, the microhardness measurement curves have different appearances (Figure 5). Figure 5c shows the microhardness distributions for both the SSR and conventional specimens after one-sided TIG welding. The microhardness distribution shows a somewhat increased microhardness in the fusion zone for both specimens. This is due to the annealed condition of the base material, which significantly reduced the alloy's microhardness. According to [PERSON] et al., because of the substantial addition of Mg from the 5087 filler metal into the molten pool, the solid solution strengthening in the weld pool zone (compared to the base metal) is enhanced, reducing the extent of softening compared to the heat-affected zone [33]. Therefore, similar to this research, the somewhat increased microhardness of the weld metal after the welding procedure is due to the AlMg5 filler metal's increased Mg content. Similar microhardness distributions for all specimens welded with the TIG procedure indicates that, despite the hand-welding procedure, both specimens were welded with similar heat inputs. There were also similar microhardness distributions for both the SSR and conventional specimens after the two-sided TIG welding (Figure 5d). However, there was a drop in the microhardness only in the middle of the weld zone. This is due to the incompletely filled groove and, therefore, increased porosity. Despite this drop in the middle of the weld zone, the overall microhardness distribution was from 50 HV to 63 HV, which is higher than in other specimens welded with the procedure using a higher heat input. It is known that the microstructure of Al-Mg-Si alloys is highly temperature-sensitive [33]. The microhardness measurements in this research are similar to previous research in which 6061 aluminum alloy in a solid solution state was welded [34]. In Table 3 are presented the results of the tensile testing. Similar to the microhardness distribution comparison for both the conventional and SSR specimens (Figure 5), it can be concluded from the tensile testing results that both kinds of specimens, for all welding procedures, had similar mechanical properties (Table 3). Overall, the MIG-welded specimens had the highest ultimate tensile strength. For the welded solid-state-recycled specimens, the ultimate tensile strength was lower by 10 MPa compared to the welded conventional specimens; however, the elongation was about 7% higher. These results are comparable, or somewhat lower, compared to previous research that dealt with welding 6082 aluminum alloy [35; 36; 37].