Corrosion evaluation of friction stir welded lap joints of AA6061-T6 aluminum alloy

Farhad GHARAVI, Khamirul A. MATORI, Robiah YUNUS, Norinsan Kamil Othman, Firouz FADAEIFARD

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

Corrosion behavior of friction stir lap welded AA6061-T6 aluminum alloy was investigated by immersion tests in sodium chloride + hydrogen peroxide solution. Electrochemical measurement by cyclic potentiodynamic polarization, scanning electron microscopy, and energy dispersive spectroscopy were employed to characterize corrosion morphology and to realize corrosion mechanism of weld regions as opposed to the parent alloy. The microstructure and shear strength of welded joint were fully investigated. The results indicate that, compared with the parent alloy, the weld regions are susceptible to intergranular and pitting attacks in the test solution during immersion time. The obtained results of lap shear testing disclose that tensile shear strength of the welds is 128 MPa which is more than 60% of the strength of parent alloy in lap shear testing. Electrochemical results show that the protection potentials of the WNZ and HAZ regions are more negative than the pitting potential. This means that the WNZ and HAZ regions do not show more tendencies to pitting corrosion. Corrosion resistance of parent alloy is higher than that for the weldments, and the lowest corrosion resistance is related to the heat affected zone. The pitting attacks originate from the edge of intermetallic particles as the cathode compared with the Al matrix due to their high self-corrosion potential. It is supposed that by increasing intermetallic particle distributed throughout the matrix of weld regions, the galvanic corrosion couples are increased, and hence decrease the corrosion resistance of weld regions.

Original languageEnglish
Pages (from-to)684-696
Number of pages13
JournalTransactions of Nonferrous Metals Society of China (English Edition)
Volume26
Issue number3
DOIs
Publication statusPublished - 1 Mar 2016

Fingerprint

lap joints
aluminum alloys
corrosion
Aluminum alloys
Welds
friction
aluminum
pitting
Friction
Corrosion
Pitting
heat affected zone
evaluation
corrosion resistance
Corrosion resistance
shear strength
Shear strength
submerging
attack
Intermetallics

Keywords

  • AA6061 alloy
  • friction stir welding
  • intermetallic particles
  • lap joints
  • pitting corrosion
  • welding process

ASJC Scopus subject areas

  • Geotechnical Engineering and Engineering Geology
  • Materials Chemistry
  • Metals and Alloys
  • Condensed Matter Physics

Cite this

Corrosion evaluation of friction stir welded lap joints of AA6061-T6 aluminum alloy. / GHARAVI, Farhad; MATORI, Khamirul A.; YUNUS, Robiah; Othman, Norinsan Kamil; FADAEIFARD, Firouz.

In: Transactions of Nonferrous Metals Society of China (English Edition), Vol. 26, No. 3, 01.03.2016, p. 684-696.

Research output: Contribution to journalArticle

GHARAVI, Farhad ; MATORI, Khamirul A. ; YUNUS, Robiah ; Othman, Norinsan Kamil ; FADAEIFARD, Firouz. / Corrosion evaluation of friction stir welded lap joints of AA6061-T6 aluminum alloy. In: Transactions of Nonferrous Metals Society of China (English Edition). 2016 ; Vol. 26, No. 3. pp. 684-696.
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