PSI - Issue 72

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

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advanced materials that can withstand the demanding conditions faced by patrol boats, ensuring their long-term reliability and performance. 2. Types of aluminum alloys in marine applications 2.1. Aluminum alloy 2xxx series The 2xxx series aluminum alloys, such as aluminum 2024, are widely utilized in maritime and other industrial applications due to their combination of high strength, lightweight characteristics, and corrosion resistance (Mao et al., 2022). These alloys are composed of elements such as Al, Cu, Mg, Fe, Si, and Mn (Fang et al., 2022). The 2xxx series aluminum alloys offer advantages including excellent corrosion resistance, high strength, and a superior strength-to-weight ratio (Tian et al., 2024). The addition of silicon (Si) reduces the melting point, enhances fluidity during casting, and improves the alloy's strength. Meanwhile, magnesium (Mg), with its relatively higher solubility, provides substantial strengthening effects through unique precipitation hardening mechanisms, driven by the formation of Al7Cu2Fe and AlCuFeMnSi phases (Mao et al., 2022). 2.2. Aluminum alloy 5xxx series Aluminum Alloy 5052 consists of several main elements that provide superior properties, namely: magnesium (Mg) 2.2 – 2.8%, silicon (Si) 0.25%, chromium (Cr) 0.15 – 0.35%, iron (Fe) 0.4%, copper (Cu) 0.1%, manganese (Mn) 0.1%, and zinc (Zn) 0.1% (Farooq et al., 2024). This combination of elements provides good mechanical strength and high corrosion resistance, making them ideal for applications in maritime environments (Jebaraj et al., 2020). The 5xxx series aluminum alloy belongs to the category of magnesium-aluminum alloys, which are known for their good corrosion resistance, especially in seawater and corrosive maritime environments (Li, 2022). 2.3. Aluminum alloy 6xxx series The 6xxx series aluminum alloy (AA6061) consists of 0.8% Mg, 0.4% Si, and 96.4% Al (Deyab et al., 2020). This alloy is well-suited for maritime applications due to its excellent strength-to-weight ratio and ease of fabrication. However, its corrosion resistance can be compromised in salt-laden environments (Venugopal et al., 2023). Although 6xxx aluminum exhibits good corrosion resistance in moderately aggressive conditions, additional protection, such as coatings or the use of corrosion inhibitors like extracts from Terminalia Glaucescens Planch, can significantly enhance its performance in harsher marine environments (Olakolegan et al., 2020). AA7050 is an aluminum alloy that belongs to the 7xxx series of aluminum alloys, known for its high strength and resistance to deformation. The alloy is generally composed of approximately 90% aluminum (Al) as the main component, with the addition of reinforcing elements such as zinc (Zn), which ranges from 5% to 6%, and magnesium (Mg), around 2% to 3%. Other elements, such as copper (Cu), manganese (Mn), and silicon (Si), are also added in small amounts to improve mechanical properties and corrosion resistance (Yan et al., 2024a). Although AA7xxx offers excellent performance in structural applications, it is susceptible to stress corrosion cracking (SCC), particularly when exposed to chloride-ion-containing environments, which can lead to a decrease in structural strength and premature material failure (Li et al., 2024). Therefore, an understanding of the composition and corrosion behavior of these alloys is essential for applications in harsh environments (Zhou et al., 2023). 3. Material degradation due to corrosion Corrosion in aluminum alloys poses a significant challenge in the construction of patrol boats, particularly in harsh maritime environments. Various studies have highlighted significant degradation mechanisms caused by corrosion, including pitting, intergranular corrosion, and stress corrosion cracking (SCC), which directly affect structural 2.4. Aluminum alloy 7xxx series