Corrosion Behavior of 8090 Al-Li Alloy

Abstract An evaluation was conducted of the corrosion behavior of 8090 aluminum-lithium (Al-Li) alloy (UNS A98090), when aged under various conditions and subjected to corrosion in a solution of 3.5% NaCl + 1% H2O2. Susceptibility to pitting, intergranular corrosion, and exfoliation corrosion was shown to be influenced by heat treatment, which reduced from natural aging, through overaging to peak aging. Materials with peak aging showed low corrosion resistance. The decreased corrosion resistance corresponded to decreased corrosion potential of the alloy. Insoluble constituents were susceptible to corrosion. The corrosion extended along grain boundaries. Al-Li alloys showed mismatched tensile strength and stress corrosion resistance. The growth rate of stress corrosion cracks was large in the peak-aged state. The growth rate was strengthed by overaging, but tensile strength was reduced. That problem was solved by retrogression and reaging processing.