The A1-2.79Li-1.3Cu-0.7Mg-0.12Zr(8090) alloy has excellent resistance to intergranularand exfoliation corrosion as naturally aged, worst as peak aged and rather better asunderaged than as overaged. The corrosion behaviour of the alloy is closely dependent on itsmicrostructure. Under the peak aging condition, the coarse T2 phase, which is continuouslydistributed along grain boundaries, has so low corrosion potential in comparison with the ma-trix, this makes the corrosion resistance of the alloy to be deteriorated by anodic dissolutionalong grain boundaries.
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