Localized corrosion behavior of alloy 2090. The role of microstructural heterogeneity

R. G. Buchheit, J. P. Moran, G. E. Stoner

Research output: Contribution to specialist publicationArticle

163 Scopus citations

Abstract

The pitting and intergranular corrosion behavior of alloy AA 2090 (Al-2Li-3Cu UNS A92090) in a 3.5 wt% NaCl solution was investigated. Two different types of pitting mechanisms were identified. The first type attributed to dissolution of the subgrain boundary phase T1. A direct correlation between increased subgrain boundary precipitation and increased subgrain boundary pitting was observed. The second type of pitting involved enhance local galvanic attack of the matrix material surrounding Al-Cu-Fe constituent particles. With this type of attack, large pits formed around constituents which occurred randomly throughout the plate. Associated with constituent particle pitting was a form of localized attack designated as continuous subgrain boundary dissolution. This form of corrosion was observed on all specimens used. It was only seen, however, ever, in regions adjacent to the largest pits on the specimen, suggesting the influence of an occluded (crevice) environment. Simulated crevice experiments revealed that an acidic crevice solution developed with time. This environment is suspected to contribute to the continuous subgrain boundary dissolution in the vicinity of the constituent particles.

Original languageEnglish
Pages610-617
Number of pages8
Volume46
No8
Specialist publicationCorrosion
DOIs
StatePublished - 1990

ASJC Scopus subject areas

  • General Chemistry
  • General Chemical Engineering
  • General Materials Science

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