PSI - Issue 82

Goran Vukelić et al. / Procedia Structural Integrity 82 (2026) 24 – 29 Vukelić et al. / Structural Integrity Procedia 00 (2026) 000–000

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aluminum rapidly forms aluminum oxide films, along with salt deposits from seawater. The upward trend shows that this layer thickens steadily, acting as a protective barrier to some degree, but also hiding the true metal loss beneath. Specimens weighed after cleaning show a slight decrease in mass, of 0.1 % at three months, and 0.25 % at six months. After cleaning, the mass loss becomes evident, indicating true metal dissolution beneath the corrosion products. The decrease with time shows a progressive corrosion rate, approximately constant over the six months. The total loss of 0.25 % is small, meaning AlSi10Mg0.6 exhibits good corrosion resistance, typical for aluminum alloys with protective oxide layers. Engineering stress-strain diagrams given in Fig. 3 show the change in apparent tensile strength over the period of exposure. The initial curvature of all three diagrams is quite similar, indicating minimal degradation in stiffness due to marine exposure. Ultimate tensile strength (UTS) of the material kept at the room atmosphere is 287 MPa, while apparent UTS after a three-month exposure period is 299 MPa, and after a six-month exposure period is 282 MPa. The increase after three months could be due to surface work-hardening or precipitation effects induced by exposure to saline conditions and slight oxidation. The decrease after six months indicates the onset of corrosion-induced damage, such as pitting corrosion or microcrack initiation, which compromises the load-bearing capacity. Specimens kept at the room atmosphere exhibit a strain of around 9 %, while those exposed to the natural marine environment exhibit reduced strain of about 6 %. Marine corrosion, especially in Al–Si alloys, tends to initiate localized corrosion (pitting) and microvoids at the Si-rich boundaries. These act as stress concentrators, reducing the alloy’s ability to plastically deform before fracture, which could be a reason for such a reduction in strain rate. To develop a more comprehensive understanding of the long-term behaviour of the tested aluminium alloy under marine conditions, the exposure period should be extended to 12 or 24 months. Additionally, comparing the outcomes of natural seawater exposure with those obtained from standardized accelerated corrosion tests performed under controlled laboratory conditions would provide valuable complementary insights. Although the alloy retains high corrosion resistance, attention should also be given to progressive localized attack over time, typical for aluminum alloys. Acknowledgements Funded by the European Union – NextGenerationEU, under the University of Rijeka project PU-175, uniri-iz-25 111, "Assessment of 3D-Printed Material Corrosion Using Artificial Intelligence - 3D-Cortelligence". References Basan, R., Marohnić, T., Božić, Ž., Marković, E., 2025. Investigation of methods for estimation of fatigue parameters and behavior of aluminum and titanium alloys. Procedia Structural Integrity, European Conference on Fracture 2024 68, 782–787. https://doi.org/10.1016/j.prostr.2025.06.130 Bogdanovic, M., Ivosevic, S., 2025. Offshore Wind Energy Potential: Assessing Capacity Factor and Electricity Generation in Montenegro. Pomorstvo 39, 150–166. https://doi.org/10.31217/p.39.1.12 Calvo-García, E., Barro, Ó., Pou-Álvarez, P., Badaoui, A., Wallerstein, D., Riveiro, A., Comesaña, R., 2025. Fatigue crack growth and fracture toughness of shot peened 6060 T6 aluminium alloy. Procedia Structural Integrity, European Conference on Fracture 2024 68, 809–814. https://doi.org/10.1016/j.prostr.2025.06.134 Dantas, A., Dantas, R., Cipriano, G.P., de Jesus, A., Lesiuk, G., Fonseca, C., Moreira, P., Correia, J.A.F.O., 2024. A methodology to evaluate seawater corrosion on quasi-static tensile properties of a structural steel. Engineering Failure Analysis 164, 108613. https://doi.org/10.1016/j.engfailanal.2024.108613 Guo, Z., Hou, Y., Zhu, C., Liu, S., Pu, Y., Chen, S., 2025. Microstructural evolution and corrosion-assisted failure mechanism of 7075-T6 aluminum alloy under elastic-plastic stress: An integrated numerical and experimental investigation. Engineering Failure Analysis 178, 109672. https://doi.org/10.1016/j.engfailanal.2025.109672 Köckritz, J., Kögler, D., Szlosarek, R., Langenhan, S.G., Kröger, M., 2025. The effect of surface treatment on the fatigue life of aluminium 2139 AM components manufactured additively by PBF-LB/M. Procedia Structural Integrity, European Conference on Fracture 2024 68, 962–968. https://doi.org/10.1016/j.prostr.2025.06.157 Kopic, M., Mihaljec, B., 2025. Environmental Ageing of Structural Materials in Shipbuilding and Marine Engineering – A Review. Scientific Journal of Maritime Research - Pomorstvo 39, 235–253. Mao, Y., Zhu, Y., Deng, C.-M., Sun, S., Xia, D.-H., 2022. Analysis of localized corrosion mechanism of 2024 aluminum alloy at a simulated marine splash zone. Engineering Failure Analysis 142, 106759. https://doi.org/10.1016/j.engfailanal.2022.106759