PSI - Issue 72

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

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reliability. Tian et al. (2024) demonstrated that aluminum 2524-T3 suffers from severe corrosion in tropical atmospheres with high chloride ion (Cl⁻) content, high humi dity, and elevated temperatures, which promote increased pitting and intergranular corrosion. Fig. 2 illustrates the surface morphology of 2524-T3 aluminum alloy after exposure for 6, 12, and 24 months in three different atmospheric environments: Site A (temperate marine climate), Site B (subtropical marine climate), and Site C (tropical marine climate). After 6 months, mild corrosion was observed at Sites A and B, with small corrosion cavities and largely intact surfaces. In contrast, at Site C, exfoliation corrosion had already begun to develop significantly. After 12 months, corrosion in Sites A and B intensified, with deeper and larger cavities forming. In contrast, at Site C, corrosion became more severe, with metal particles beginning to exfoliate. After 24 months, Sites A and B exhibited expanded corrosion areas, although these remained less severe compared to Site C, where the surface became heavily damaged, with extensive exfoliation and a rugged appearance. The figure highlights that the tropical environment at Site C resulted in the most severe corrosion, driven by high humidity, high temperatures, and intense chloride ion deposition, compared to the milder effects observed at the other sites. This type of corrosion causes significant mechanical damage, including reductions in tensile strength and elastic modulus, indicating that localized defects can serve as initiation points for cracks, thereby threatening structural integrity (Tian et al., 2024).

Fig. 2. Surface morphologies of 2524-T3 aluminum alloy after exposure (Tian et al., 2024).

Additionally, Yan et al. (2024) emphasized the role of tensile stress in accelerating pitting corrosion in aluminum 7050. This stress creates localized concentrations at defect sites, thereby hastening the progression of corrosion and triggering the formation of cracks. This phenomenon is particularly relevant for patrol boat operations, which frequently encounter high mechanical stresses from waves and maneuvers (Yan et al., 2024b). Meanwhile, Wu et al. (2024) compared SCC mechanisms with Corrosion-Induced Mechanical Property Degradation (CIMPD) in the 7050 T7451 alloy. Fig. 3 illustrates the SEM morphology of corrosion products on the surface of 7050-T7451 aluminum alloy in environments wit h and without bisulfite (HSO₃⁻), along with the chemical composition at specific points. In