Effect of Rolling-Induced Microstructural Evolution and Post-Heat Treatment on the Corrosion Mechanisms of Al–Li Alloy 8090-T3 in Simulated Seawater

Aluminum–lithium (Al–Li) alloys are widely used in aerospace applications because of their high strength-to-weight ratio and reduced density. However, their corrosion behavior can be significantly affected by thermomechanical processing and exposure to chloride-containing environments. In the present study, the corrosion behavior of AA8090-T3 Al–Li alloy was investigated in 3.5 wt.% NaCl solution under simulated marine conditions. The specimens were extracted from a plate and subsequently subjected to annealing and rolling treatments using a specially designed wedge-shaped geometry to generate a continuous strain gradient, enabling the evaluation of deformation-dependent corrosion behavior across different deformation zones. The corrosion behavior was evaluated using potentiodynamic polarization, immersion testing, and surface characterization techniques. The results revealed significant variations in corrosion behavior with thermomechanical condition and deformation zone. The T3 temper-rolled specimen exhibited superior corrosion resistance compared to the annealed and rolled conditions. The lowest corrosion rate of 0.003 mpy was observed for the highly deformed T3 temper-rolled condition, whereas annealed specimens showed higher corrosion susceptibility associated with localized corrosion attack and precipitate-related galvanic activity. Surface characterization confirmed the formation of aluminum hydroxide- and copper oxide-based corrosion products. The study demonstrates the effectiveness of the wedge-shaped rolling methodology for evaluating zone-dependent corrosion behavior in thermomechanically processed AA8090 alloy.