Electrochemical Analysis of the Corrosion Resistance of the Al-Alloy EN AW-5454-D and Its Welded Joints

An electrochemical analysis of the corrosion resistance of the Al-alloy EN AW-5454-D and its welded joints made by MIG (Metal Inert Gas) and by laser hybrid (LH) welding, was performed on this study. All the tested samples had a thickness of 4 mm, whereby all the samples` surfaces were cleaned with a plasma cleaning process before the elec-trochemical testing to reduce the impact of contamination. The electrochemical be-haviour was investigated in a 3.5 wt.% NaCl solution over immersion periods of 1 hour, 7 days and 30 days, using electrochemical techniques and surface analysis. The ob-tained results show that the welding processes (MIG and LH) caused microstructural heterogeneities that reduce the corrosion resistance of the weld. The MIG welded Al-alloy showed worse properties than the LH welded in the electrochemical tests, as it had a higher corrosion current density, lower polarisation resistance and higher layer capacitance. Due to long-term exposure to the immersion solution, despite the reduced susceptibility to uniform corrosion, the Al-alloy samples and their welds remained susceptible to pitting corrosion.