Corrosion behaviour of AA2198-T8 and AA2024-T3 alloy in 3.5 aqueous solution

摘要

The present work investigates the corrosion resistance of the Al-Cu-Li (2198) aluminium alloy in T8; a comparison against Al-Cu (2024) alloy is attempted. Tensile specimens were pre-corroded for different exposure times to 3.5 wt.% NaCl solution and immediately afterwards they were tested in tension. Corrosion exposure was found to degrade all aspects of the tensile behaviour of AA2024-T3 alloy at a higher level compared to the respective degradation of the tensile properties of AA2198-T8 alloy especially at long exposure times where the pitting corrosion mechanism takes place. Regarding the elongation at fracture, AA2024-T3 was found to degrade at much higher rates even at the short exposure times where hydrogen embrittlement is the dominant degradation mechanism. It was thus definitely concluded that Al-Cu-Li alloy is superior concerning corrosion resistance, since it maintains higher percentages of the initial (uncorroded) values of its tensile properties, against AA2024.