Investigation of the nugget zone corrosion behavior in friction stir welded lap joints of 6061-T6 aluminum alloy

Abstract

The corrosion behavior at different positions (top and bottom) of the weld nugget zone along the thickness plates in AA6061-T6 aluminum alloys welded by friction stir lap welding, under the conditions of 1000 rpm-60 mm/min and 900 rpm-40 mm/min in a 3.5 wt% NaCl solution, was investigated by Tafel polarization at ambient temperature. The morphology of the nugget zone corroded surfaces was analyzed by scanning electron microscopy together with energy dispersive spectroscopy (SEM-EDS) as well as atomic force microscopy (AFM). It was found that the top half of the nugget zone has a better corrosion resistance than that of the bottom half for both welding conditions. A localized pit dissolution with combined intergranular corrosion are the dominant corrosion types across different positions of the nugget zone for various welding conditions and in the parent alloy.

Effect of friction stir lap weld and post weld heat treatment on corrosion behavior of dissimilar aluminum alloys

“…Hence, nugget area contained more of the anodic V-95 alloy, which explains the higher corrosion susceptibility. Gharavi et al 24 has also reported that pitting corrosion resistance of friction stir lap welded AA6061-T6 decreases along the through-thickness direction of the weld nugget. The residual stress in a weld joint varies in the through-thickness direction of the nugget.…”

Effect of Process Parameters on Corrosion Resistance of Aa 6101 T6 Al Alloys Welded by Friction Stir Welding

“…(Fig.3). Here E pit <E corr which indicate that pitting will occur and damage passive film which is not repairable and it will further corroded under pitting manner [9]. …”

Friction Stir Welding with Low-Medium-High Tool Travel Speed of 0.95 Mg-Al-Alloy and Pure Copper: Electrochemical and Surface Studies

“…A slightly elongated grain structure can be seen in the TMAZ zone due to the annealing effect of heat and severe plastic deformation of material around the pin edge [22]. Slightly coarse grains were seen in the HAZ zone located outside of the TMAZ zone which was affected only by the heat generation during the welding process [23]. DXZ is of great industrial interest due to the new grains being smaller than the initial grains that enhances the mechanical properties at room temperature.…”