Welding and galvanic coupling effects on the electrochemical activity of dissimilar AA2050 and AA7050 aluminum alloys welded by Friction Stir Welding (FSW)

Author(s)

de Viveiros, Barbara Victoria G. ; da Silva, Rejane Maria P. ; Donatus, Uyime ; Costa, Isolda

• Document type: Journal article
• Source: Electrochimica Acta; v. 449, p. 15-pg., 2023-03-20.

Abstract

In this work, the effects of friction stir welding (FSW) on the microstructure and electrochemical activities of dissimilar AA2050 and AA7050 aluminum alloys have been investigated. Local electrochemical tests supported by surface analytical characterization were used to study the local electrochemical activities developed along the weld zones of the dissimilar alloys. The investigation was carried out on the cross-section of the welded Al alloys. The results showed that the friction stir welding (FSW) of the dissimilar alloys affected the microstructure and the electrochemical behavior of the different regions (HAZ, TMAZ, SZ) formed by the welding process. Scanning vibrating electrode technique (SVET) and micropotentiometry by using an ion-selective microelectrode showed that TMAZ was the zone with the highest electrochemical activity. This zone corresponded to the transition region between the two welded alloys. The high electrochemical activity observed in this region was associated with the effect of welding on the microstructure and, also, with the galvanic coupling between the two alloys, where the alloy AA7050 acted as an anode and the AA2050 as a cathode. Preferential corrosion attack on the AA7050 alloy was also evident. (AU)

• FAPESP's process: 18/06880-6 - Use of Localized Electrochemical Techniques for the Study of Corrosion of of High Strength Aluminum Alloys Joined by Friction (FSW).
• Grantee: Rejane Maria Pereira da Silva
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 17/03095-3 - Investigation on corrosion susceptibility of Al-Cu-Li alloys by friction stir welding (FSW) through scanning vibrating electrode technique (SVET)
• Grantee: Uyime Donatus
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 13/13235-6 - Investigation on the localized corrosion and the fatigue corrosion resistance of high strength aluminum alloys joined by friction stir welding (FSW)
• Grantee: Isolda Costa
• Support Opportunities: Research Projects - Thematic Grants