Effect of Weld Seams on Corrosion Following Porthole Die Extrusion of Aluminum Tubes

The influence of weld seam defects on corrosion was investigated in aluminum tubes produced using the porthole die extrusion process. These defects occur because of the presence of intermetallic compounds at the joint interface, hindering solid-state diffusion by forming strong bonds with aluminum and dissimilar metals. Consequently, corrosion occurs and propagates along the depth direction of the weld seam. To address this issue, a lean alloy design approach was employed, and the corrosion resistance of the prepared lean alloyed Al–Mn–Zr alloy was evaluated. Microstructure analysis revealed the presence of smaller precipitates in the Al–Mn–Zr alloy than in the AA3003 alloy, which has larger precipitates. The Al–Mn–Zr alloy exhibits better corrosion resistance and uniform corrosion behavior than the AA3003 alloy, which exhibits severe localized corrosion along the weld seam. Graphical Abstract