Corrosion Behavior of Friction Stir Welded Joints in Aluminum Alloys (AA2000, AA5000, AA7000, AA8000)

Abstract

Friction Stir Welding (FSW) demonstrates superior corrosion resistance in aluminum alloys compared to conventional techniques like arc and laser welding, owing to reduced heat-affected zones (3–5 mm) and refined microstructures. Environmental conditions significantly influence corrosion behavior, with marine (3.5% NaCl) and acidic (pH 3) environments accelerating pitting and intergranular corrosion in AA5000 and AA2000 alloys, respectively. Alloy composition plays a critical role: AA6061-T6 (AA6000 series) exhibits lower pitting rates (0.18 mm/year) than copper-rich AA2024 (0.34 mm/year), while optimized Li/Cu ratios in AA8090 (AA8000 series) reduce exfoliation corrosion by 25%. Mechanical-corrosion synergy reveals residual stresses and microstructural features, such as low-angle grain boundaries, directly impact stress corrosion cracking (SCC) and pitting resistance,Industrial applications in aerospace, marine, and infrastructure highlight FSW’s advantages, including 30% lower SCC risk in AA7000 fuselage panels and 50% extended service life for AA5083 ship hulls. Enhanced predictive modeling, integrating environmental variables, aligns with experimental data, supporting optimized welding parameters and post-weld treatments like laser peening and anodizing,This study underscores the interplay between alloy design, welding parameters, and environmental adaptation to enhance durability in critical engineering applications.