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Indexed by:期刊论文

Date of Publication:2018-09-01

Journal:MATERIALS RESEARCH EXPRESS

Included Journals:SCIE

Volume:5

Issue:9

ISSN No.:2053-1591

Key Words:corrosion behavior; aluminum alloy/galvanized steel dissimilar metal joint; refilled friction stir spot welding; electrochemical analysis

Abstract:The cross-sectional corrosion behavior of refilled friction stir spot welded joint of aluminum alloy and galvanized steel was investigated by immersion corrosion method. Scanning electron microscopy and laser confocal microscopy examination revealed that both pin-affected zone and the sleeve-affected zone were severely corroded due to the presence of Zn-rich layers. Microcracks in the Zn-rich layers accelerated the formation of pitting corrosion. In addition, the aggregation of Zn and Mg elements led to intergranular corrosion. Exfoliation corrosion happened at the regions near the joint interface. The pitting corrosion initiated from the interface between the Fe-rich phase particles and the surrounding aluminum alloy substrate. The high self-corrosion potential of Fe-rich phase particles caused anodic dissolution of the adjacent aluminum alloy substrate.