Systematic examination of precipitation phenomena associated with hardness and corrosion properties in friction stir welded aluminium alloy 2024

Y. S. Sato, S. Kurihara, H. Kokawa

Research output: Contribution to journalReview articlepeer-review

7 Citations (Scopus)

Abstract

The mechanical and corrosion properties of friction-stir welded, precipitation hardenable, AA2024 strongly depend on the volume fraction, size and distribution of the strengthening precipitates, and thus it is necessary to precisely understand the relationship between these properties and the precipitate distribution to improve the properties of the weld. In the present study, the hardness profile and the corrosion properties were systematically correlated with the precipitate distribution in AA2024-T4 friction stir (FS) welded at different welding parameters. The hardness profile of the weld could be explained by the density of GPB zones. Two hardness reduction regions were found in the HAZ. One was characterized by overageing and the other by the absence of precipitates. Overageing could be effectively suppressed by using low heat input welding parameters. The weld had a region with lower corrosion resistance in the HAZ proximal to the stir zone, which was due to presence of many S phases. It is suggested that the corrosion was attributable to the dissolution of S (S') phases during the corrosion tests of AA2024. Reduction of the hardness and the corrosion resistance in the HAZ could be alleviated by a decrease in heat input during FSW.

Original languageEnglish
Pages (from-to)39-47
Number of pages9
JournalWelding in the World
Volume55
Issue number11-12
DOIs
Publication statusPublished - 2011

Keywords

  • Age hardening
  • Corrosion
  • Friction stir welding
  • Hardness

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys

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