Galvanic and asymmetry effects on the local electrochemical behavior of the 2098-T351 alloy welded by friction stir welding

On the local corrosion behavior of coupled welded zones of the 2098-T351 Al-Cu-Li alloy produced by Friction Stir Welding (FSW): An amperometric and potentiometric microelectrochemical investigation

“…Other works have reported correlations between the onset of localized corrosion features and the microstructures in the different welded zones of FSW Al-Cu-Li alloys [19,26,27].…”

“…Clusters of coarse intermetallic particles were more evident in the TMAZ of the RS, resulting in the greater susceptibility of this zone to localized corrosion [17]. More recently, Milagre et al [19] showed the influence of asymmetry effects from the FSW process on the localized corrosion susceptibility of the 2098-T351 Al-Cu-Li alloy welded by FSW, and they reported that the electrochemical activity was higher in the RS compared to the AS.…”

“…The T1 phase is reported to be highly active due to the presence of Li, and its fast selective dissolution leads to Cu-enrichment, polarity reversal and, subsequently, dissolution of the Al matrix, in aggressive environments [1,3,23]. However, the amount and morphology of this phase are modified by the FSW process [19], while causing distinct degrees of thermal gradients and mechanical deformation [5,8].…”

“…Even more scarce are the reports on the corrosion behavior of the 2098 Al-Cu-Li alloy [28][29][30]. In addition, few attempts have been made to investigate these localized processes using localized electrochemical techniques [19,31], although the applicability of localized electrochemical techniques for the investigation of the corrosion activity of some Al-Cu-Li alloys has been reported in the literature [7,29,30,32]. Thus, scanning probe techniques with electrochemical selectivity, such as the scanning vibrating electrode technique (SVET), scanning electrochemical microscopy (SECM) and the local electrochemical impedance spectroscopy (LEIS), were employed to study galvanic coupling effects on the local electrochemical activity due to the different zones in contact in dissimilar Al-alloys welded by FSW, namely for the 7050/2024 [33], 2024/7475 [34], and 2050/7449 systems [35].…”

Mechanical behavior associated with metallurgical aspects of friction stir welded Al–Li alloy exposed to exfoliation corrosion test

“…In terms of WNZ, which is affected by both thermomechanical and stirring, both δ′ and β′ (Al 3 Zr) are the major strengthening phases [14,16,23,24]. Due to these microstructural changes, many researchers have studied the corrosion performance of welded alloys [25][26][27][28]. Liu et al [22] found that the high proportion of T 1 phase reduced the corrosion sensitivity of the 2198 Al-Li alloy.…”