PSI - Issue 72

Aria Pranata et al. / Procedia Structural Integrity 72 (2025) 383–391

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the environment without bisulfite, the corrosion product layer is relatively thin and less dense, primarily composed of aluminum oxide and hydroxide. Conversely, the environment with bisulfite shows a thicker and more heterogeneous corrosion layer with higher sulfur content, indicating the formation of aluminum hydroxy sulfite. The addition of bisulfite accelerates corrosion by lowering the solution pH, resulting in the faster formation of dense corrosion products. This intensified corrosion not only accelerates material degradation but also affects the alloy's mechanical properties by acting as a stress concentrator, underscoring the critical role of environmental factors in the corrosion behavior of aluminum alloys. The addition of HSO3- exacerbates the corrosion of 7050-T7451 alloy, thereby increasing the degradation percentage caused by corrosion products, hydrogen, and corrosion damage. The relative contribution of different factors shows considerable consistency across the two environments, with corrosion-induced hydrogen being the controlling factor in the CIMPD of the 7050-T7451 alloy. Their findings showed that CIMPD, which involves hydrogen accumulation during corrosion, has a more severe impact, causing a decrease in elongation of up to 70%. Hydrogen embrittlement accelerates material failure, particularly in acidic environments commonly found in waters with high sulfur pollution (Wu et al., 2024).

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Fig. 3. SEM morphology in solution (a) without HSO 3- ; (b) with HSO 3- (Wu et al., 2024).

Chekalil et al. (2024) investigated the effects of corrosion on Friction Stir Welded (FSW) joints in aluminum AA3003, a material frequently used in ship construction. Their study examined the impact of various corrosive environments, including sodium chloride, hydrogen chloride, and ethylene glycol, on the mechanical properties of welded joints, particularly in the heat-affected zones (HAZ), which were found to be more susceptible to corrosion than the core weld zones. The researchers conducted tensile strength and fatigue resistance tests at varying temperatures, ranging from 25°C to 85°C, to assess degradation patterns. The combination of uniform corrosion and pitting resulted in significant surface damage, although the maximum tensile strength of the joints remained relatively stable. Notably, the addition of inhibitors, such as ethylene glycol, effectively slowed the propagation of corrosion cracks, doubling the service life of the welded joints. These findings highlight the potential of material innovations and corrosion inhibitors to enhance the durability of structural components in patrol boats (Chekalil et al., 2024). The studies collectively highlight that material degradation in aluminum alloys used for patrol boats is significantly influenced by environmental factors and operational stresses. Corrosive environments, particularly those with high humidity, elevated temperatures, chloride ions, and pollutants such as bisulfite, exacerbate corrosion mechanisms