Corrosion behaviour of dissimilar friction stir welded aluminium alloys reinforced with nanoadditives

Friction stir welding (FSW) is a viable technique for joining aluminium alloys that are difficult to fusion weld. However, the produced friction stir (FS) welded materials need to be improved in terms of their resistance to corrosion. The effect of nanoadditives as reinforcing materials on the corrosion behaviour of dissimilar metal/metal joints and compare with the parent metal alloys is demonstrated in the present study. Dissimilar FS welded materials were produced in plates of aluminium alloy (AA) 6082-T6 and AA5083-H111 using nanoadditives of titanium carbide (TiC) nanoparticles, multi walled carbon nanotubes (MWCNT) and cerium molybdate (CeMo) containers loaded with corrosion inhibitor 2-mercaptobenzothiazole (MBT), as reinforcing materials. The corrosion resistance of the samples with or without nanoadditives was studied by electrochemical methods. The results revealed that the incorporation of CeMo containers loaded with MBT during the FSW, enhances the corrosion resistance of the final material through the adsorption of MoO4−2 ions that come from the container shell onto the surface of both AA, as well as the formation of stable complexes between the thiol groups of MBT and the alloying metals, preventing chloride penetration. Keywords: Aluminium alloy 6082-T6, Aluminium alloy 5083-H111, Friction stir welding, Electrochemical impedance spectroscopy, Potentiodynamic polarization