Pitting corrosion resistance of anodized aluminum alloy processed by severe plastic deformation

In Joon Son, Hiroaki Nakano, Satoshi Oue, Shigeo Kobayashi, Hisaaki Fukushima, Zenji Horita

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23 Citations (Scopus)

Abstract

The effect of equal-channel angular pressing (ECAP) on the pitting corrosion resistance of anodized Al and Al-Mg alloy was investigated by electrochemical techniques in a solution containing 0.2 mol/L of AlCl 3 and by surface analysis. The time required for initiating pitting corrosion of anodized Al was longer with ECAP than without, indicating improvement in the pitting corrosion resistance by application of ECAP. However, in anodized Al-Mg alloy, the pitting corrosion occurred earlier with ECAP than without, showing that the corrosion resistance was worse with ECAP than without. SEM and EPMA observation revealed that pitting corrosion of anodized Al occurred around the impurity precipitates and that the size of the impurity precipitates decreased as a result of the ECAP. The improvement in pitting corrosion resistance of anodized Al by ECAP appears to be attributable to a decrease in the size of impurity precipitates. On the other hand, in anodized Al-Mg alloy, cracks occurred in the anodic oxide films during initial corrosion and the cracks were larger with ECAP than without. It is assumed that the pitting corrosion was promoted by the cracks due to the higher internal stress resulting from ECAP.

Original languageEnglish
Pages (from-to)21-28
Number of pages8
JournalMaterials Transactions
Volume48
Issue number1
DOIs
Publication statusPublished - Jan 1 2007

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All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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