Info

Title:

Effect of heterogeneous microstructure on corrosion resistance of the new-type aluminum-lithium alloy AA2099-T8

Author(s):

Ma Yanlong 1;  2

Keywords:

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CLC:

PACS:

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DOI:

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DocumentCode:

Abstract:

State-of-the-art research progress on microstructure, corrosion resistance and anodizing behavior of the third generation aluminum-lithium alloys has been reviewed, with particular focus on the effect of microstructure on corrosion resistance of the new-type aluminum-lithium alloy AA2099-T8 before and after anodizing. It was found that two types of localized corrosion occurred in the alloy in 3.5% NaCl solution, namely metastable localized corrosion and severe localized corrosion. The metastable localized corrosion is ascribed to Al-Fe-Mn-Cu-(Li) constituent particles while the severe localized corrosion is associated with localized plastic deformation and heterogeneous precipitation of the T1(Al2CuLi) phase. During tartaric-sulphuric acid anodizing (TSA), the Al-Fe-Mn-Cu-(Li) constituent particles behaved differently compared with the alloy matrix, leading to the formation of discontinuities in the anodic film, which deteriorates the corrosion resistance of the anodized alloy.