Assessment of the Corrosion Behavior of Friction-Stir-Welded Dissimilar Aluminum Alloys

Abstract

The fuel consumption of high-density automobiles has increased in recent years. Aluminum (Al) alloy is a suitable material for weight reduction in vehicles with high ductility and low weight. To address environmental problems in aircraft and maritime applications, in particular rust development and corrosion, the current study assesses the corrosion behavior during friction stir welding (FSW) of two dissimilar Al alloys (AA6061 and AA8011) in various corrosive conditions using salt spraying and submersion tests. Two acidic solutions and one alkaline solution are used in these tests, which are performed at room temperature. The two specimens (AA6061 and AA8011) and the weld region are suspended in a salt spraying chamber and a 5 wt.% NaCl solution is continually sprayed using the circulation pump for 60 h, with the specimens being weighed every 15 h to determine the corrosion rates. According to the salt spraying data, the weld zone has a higher corrosion resistance than the core components. For twenty-eight days, individual specimens are submerged in 3.5 wt.% HCl + H2O and H2SO4 + H2O solutions and seawater. The weld area specimens exhibit stronger corrosion resistance than the base material specimens, and weight loss in the saltwater medium is lower when compared to the other test solutions, according to the corrosion analysis. The scanning electron microscope (SEM) analysis demonstrates that the base metal AA8011 is considerably corroded on its surface.

Corrosion Characterization of Friction Stir Weld Dissimilar Aluminium Alloy Joints

“…The findings of the microstructural evaluation of the corroded surfaces are in line with the findings of Santhosh N et al, who have reported that the formation of the oxide films on the aluminium suface inhibits further corrosion due to the passivation of the surface layer towards the catalytic reactions [16]. Further, the works of Ramesha K et al, on the corrosion of the friction stir weld surfaces have reiterated the fact that the secondary processing operations brings about microcoring and segreggation that inibits the subgranular pitting reaction and thereby reduces the rate of corrosion [17]. Rami Alfattani et al, have further studied the corrosion behaviour of the friction stir weld specimens and have revealed that the microstructural refinement at the weld zone exhibits better corrosion resistance than the base metal, due to the zonal refinement and better bonding between the atoms leading to the reduction in the crevices and imperfections, thereby reducing the corrosion at the interface [18].…”

Microstructure, mechanical and electrochemical studies of dissimilar friction stir welded aluminium alloys

“…They also found that galvanic coupling caused high corrosion density at the nugget zone. Out of all samples, less corrosion resistance was obtained for the sample welded at high rotation speed due to the formation of defects and insufficient material mixing [30][31][32].…”

Microstructural and Mechanical Behavior Investigations of Nb-Reinforced Mg–Sn–Al–Zn–Mn Matrix Magnesium Composites

“…Therefore, numerous solutions have been proposed to reduce fuel consumption and minimize the damage to the environment [2,3]. These solutions include reducing the weight of vehicles and promoting the use of lightweight alloys [4]. Magnesium (Mg), which is a lightweight metal, has drawn attention due to its property of being the lightest structural metal [5,6].…”