Mechanical properties degradation of (Al-Cu-Li) 2198 alloy due to corrosion exposure


The present work investigates the corrosion resistance of the innovative Al-Cu-Li (2198) aluminum alloy; a comparison against Al-Cu (2024) alloy is attempted. Tensile specimens were pre-corroded for different exposure times to exfoliation corrosion solution and immediately afterwards they were tested in tension. For small exposure times (< 12 h) small pits could be found on the corroded surfaces; pitting was also noticed at the small side surfaces (thickness) of the tensile specimens. Corrosion exposure seems not to essentially decrease the yield stress of AA2198 even for high exposure times, while this was not the case for AA2024. After heavy corrosion exposure (>12 h), AA2024 lost almost 30% of its initial ultimate tensile strength, while for AA2198 the respective value was only 11%. Al-Cu-Li alloy shows superior corrosion resistance in terms of maintaining higher percentages of tensile ductility; AA2198 exhibited higher remaining elongation at fracture values due to corrosion degradation for all investigated exposure times.
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