Localized corrosion in AA2099-T83 aluminum–lithium alloy: The role of intermetallic particles

• Lithium was detected in the high-copper-containing Al–Fe–Mn–Cu particles.
• The high-copper-containing particles were relatively more active.
• Localized corrosion induced by constituent particles was superficial.
• Severe localized corrosion in the alloy propagated via grain/subgrain boundaries.
• Severe localized corrosion was not related to constituent particles.

The corrosion behavior of intermetallic particles and their role in the process of localized corrosion in AA2099-T83 aluminum–lithium alloy has been investigated. It was found that both high- and low-copper containing Al–Fe–Mn–Cu-(Li) particles could result in superficial pits on the alloy, and the high level of lithium in the high-copper-containing particles rendered them electrochemically more active than the low-copper-containing particles. Additionally, severe localized corrosion was found not to be directly related to the distribution of constituent particles in the alloy. The findings are not only relevant to the understanding of corrosion mechanism but also beneficial to the evaluation of thermomechanical treatments of the alloy.