*3.1. Microstructural Features of the Base Aluminum Alloys*

Figure 3 shows the inverse pole figure coloring maps (a, b), their corresponding grain boundary maps with high angle boundaries (HABs) > 15◦ in black lines and low angle boundaries (LABs) from 5◦ to <15◦ in red lines, and the grain size distribution charts for the as-received aluminum alloys AA5754 and AA5083. The microstructures of the AA5754 and AA5083 Al-alloys in the as-received conditions revealed a recrystallized grain structure. The presented maps of both alloys showed random and fully recrystallized grain structures without pronounced textures, as indicated by the color-code legend of grain orientations and the low density of low angle grain boundaries. The average grain diameters of AA5754 and AA5083 alloys were measured to be 82.3 with a standard deviation of 29 and 93.5 μm with a standard deviation of 34, respectively, as can be seen from the corresponding distribution of grain diameters. The results of EBSD measurements of the as-received conditions demonstrated insignificant differences in the initial grain structure of the base alloys.

**Figure 3.** Microstructural characteristics of the AA5754 and AA5083 Al-alloys in the as-received condition. EBSD orientation map, corresponding grain boundaries map, and grain size distribution histograms for (**a**) AA5754 and (**b**) AA5083 Al-alloys.
