Base material location dependence of corrosion response in friction-stir-welded dissimilar 2024-to-5083 aluminum alloy joints

The effects of the base material (BM) location on the mechanical properties and the exfoliation corrosion performance of friction-stir-welded (FSWed) dissimilar 2024-to-5083 aluminum alloy joints were investigated. Scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), transmission electron microscopy (TEM), tensile tests and electrochemical experiments were conducted. The results revealed that the BM location had little effect on the tensile properties of the joints. The grain orientation spread (GOS) value of 2024 alloy side was lower than that of 5083 alloy side. Intergranular corrosion occurred mainly on the 2024 alloy side, while the grain interior of the 5083 alloy side was corroded due to the higher GOS value and dislocation density. The FSWed dissimilar joints with a superior exfoliation corrosion resistance could be achieved when the 5083 aluminum alloy with better corrosion performance was positioned on the retreating side.