## 2 Materials and Methods  
The research material were the samples of technical aluminum alloys for forming processes: EN AW-1050A, EN AW-5754 and EN AW-6060. Selected alloys are readily available and widely used as a construction material. All analyzed alloys are also easily weldable [38]. The chemical composition of the alloys is summarized in Table 1.  
The tests were carried out in two areas: tensile strength measurements (universal testing machine) and impact strength measurements (Charpy hammer). In both cases, measurements were performed without hydrogenation and after electrolytic hydrogenation of the specimens. The hydrogenation of the specimens was carried out in a Hoffman apparatus in a 0.1 N H\({}_{2}\)SO\({}_{4}\) solution. The anode was made of platinum (No. 3 in Figure 1), whereas the aluminum alloy specimens (No. 4 in Figure 1) formed the cathode in the process. The specimens were hydrogenated for 10 and 25 min. Cathodic polarization was carried out at a current of 20 mA. The hydrogenation in a Hoffman apparatus was shown in Figure 1.  
Tensile strength measurements were carried out according to PN-EN ISO 6892-1:2020-05 [39] at 20 \({}^{\circ}\)C. The test specimens were prepared as pre-cracked specimens. Pre-cracks provide better reproducibility of results compared to smooth specimens [40]. Moreover, when the location of the crack is predetermined, it is easier to measure parameters such as, e.g., crack propagation rate [41]. The specimens were prepared in accordance with \begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline
**Alloy Designation** & **Si** & **Fe** & **Cu** & **Mn** & **Mg** & **Cr** & **Zn** & **Ti** & **Others** & **Initial** \\   EN AW-1050A & 0.25 & 0.40 & 0.05 & 0.05 & 0.05 & - & 0.07 & 0.05 & - & “O” \\   EN AW-5754 & 0.40 & 0.40 & 0.10 & 0.50 & 2.60–3.60 & 0.30 & 0.20 & 0.15 & 0.15 & “O” \\   EN AW-6060 & 0.30–0.60 & 0.10–0.30 & 0.10 & 0.10 & 0.30–0.60 & 0.05 & 0.15 & 0.10 & 0.15 & “O” \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Chemical composition (standard limit of the composition) of aluminum alloys applied in measurements—percentage of alloying elements [38]. Figure 1: The hydrogenation in a Hoffman apparatus. 1—power supply, 2—amperemeter, 3—auxiliary electrode (platinum electrode), 4—analyzed aluminum alloy (cathode), and 5—electrolyte (0.1 N H\({}_{2}\)SO\({}_{4}\) solution). PN-EN ISO 6892-1:2020-05 [39]. The dimensions of the specimens were, respectively: width 10 mm, thickness 5 mm. The geometry of notch: width 1 mm, depth 4.5 mm. During the measurement, the specimens were kept in a 3% solution of chemically pure NaCl to ensure measurement in corrosive conditions (Figure 2). The measuring vessel used was a glass vessel, indifferent to the corrosive environment (3% aqueous solution of NaCl). At the point where the specimen passed through the vessel wall a gasket (No. 4 in Figure 2) made of a rubber-like material (FiberFlex) was used. The gasket ensured the vessel tightness during the measurement. The gasket was produced with the use of 3D printing technology. During the tear-off measurements, not only the force applied to the specimens was measured, but also its electrical resistance. For this purpose, electrodes were placed at the ends of the specimen, allowing the flow and measurement of electric current through the specimen (No. 5 in Figure 2). The flow of electricity made it possible to measure the resistance of the specimen. The resistance increases with the reduction of the cross-section of the specimen, and at the time of its rupture it reached its maximum value (solution resistance). The collected data of force (needed to burst the specimen) and resistance made it possible to plot the relationship between the cracking rate and the value of the stress intensity factor \(K_{1}\). Measurements were carried out for alloys without hydrogenation and for electrolytically hydrogenated alloys. A notch was cut 2 mm deep in the center of one of the side walls in a direction perpendicular to the longitudinal axis of the specimen.