Polishing-assisted galvanic corrosion in the dissimilar friction stir welded joint of AZ31 magnesium alloy to 2024 aluminum alloy

Journal Article · Fri May 15 00:00:00 EDT 2009 · Materials Characterization

DOI:https://doi.org/10.1016/j.matchar.2008.10.009· OSTI ID:21192614

Liu, C ^[1]; Bhole, S ^[1]; Cao, X; Jahazi, M ^[2]

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1. Department of Mechanical and Industrial Engineering, Ryerson University, 350 Victoria Street, Toronto, Ontario M5B 2K3 (Canada)
2. Aerospace Manufacturing Technology Centre, Institute For Aerospace Research, National Research Council Canada, 5145 Decelles Avenue, Montreal, Quebec H3T 2B2 (Canada)

Galvanic corrosion of a dissimilar friction stir welded 2024-T3 Al/AZ31B-H24 Mg joint prepared using a water-based and a non-water-based polishing solution was characterized. Microstructure and the distribution of chemical elements were analyzed using optical microscopy, scanning electron microscopy and energy dispersive X-ray spectroscopy. The stir zone polished using water-based solution was observed to be much more susceptible to galvanic corrosion attack than that obtained using non-water-based polishing solution. The location of corrosion attack was observed in the narrow regions of AZ31 Mg alloy adjacent to Al2024 regions in the stir zone. The occurrence of galvanic corrosion was due to the formation of Mg/Al galvanic couples with a small ratio of anode-to-cathode surface area. The corrosion product was primarily the porous magnesium hydroxide with characteristic microcracks and exhibited a low microhardness value.

• OSTI ID: 21192614
• Journal Information: Materials Characterization, Vol. 60, Issue 5; Other Information: DOI: 10.1016/j.matchar.2008.10.009; PII: S1044-5803(08)00309-4; Copyright (c) 2008 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 1044-5803
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM ALLOYS
CORROSION PRODUCTS
CRACKS
ELECTROCHEMICAL CORROSION
FRICTION
MAGNESIUM ALLOYS
MAGNESIUM HYDROXIDES
MICROHARDNESS
MICROSTRUCTURE
OPTICAL MICROSCOPY
POLISHING
POROUS MATERIALS
SCANNING ELECTRON MICROSCOPY
SOLUTIONS
SURFACE AREA
WATER
WELDED JOINTS
WELDING
X-RAY SPECTROSCOPY