Local electrochemical study of friction stir welded aluminum alloy assembly

• The galvanic coupling of 2050/7449 was highlighted by SECM and LEIS.
• The electrochemical activity on passive film was studied by SECM.
• Dissimilar FSW assembly of Al alloys exhibits galvanic coupling.
• LEIS shows the current distribution close to the metallic interfaces.

The friction stir welded (FSW) assembly of 2050-T8 and 7449-T79 was studied by local electrochemical techniques, namely SECM and LEIS, under non-corrosive and low corrosive conditions. During the FSW process, it generates different well defined microstructural zones giving rise to a galvanic coupling at their interfaces. SECM and LEIS measurements were carried out to investigate the local electrochemical behavior around these interfaces. SECM results clearly showed a change of the electrochemical kinetic on the passive layer between both materials in the different microstructural zones of the welded assembly whereas the LEIS techniques allowed the investigation of the interface on a larger scale.