Mechanical and electrochemical analysis of AA5083-AA7075 dissimilar alloy joints fabricated by friction stir welding

This study investigates the mechanical and electrochemical performance of dissimilar aluminum alloy joints between high-strength AA7075 and corrosion-resistant AA5083 produced by friction stir welding (FSW) for marine applications. Defect-free joints were fabricated using optimized parameters of 1100 rpm rotational speed, 50 mm/min welding speed, and 2° tool tilt angle. Microstructural analysis revealed equiaxed grain refinement of about 3 μm in the weld zone (WZ) due to dynamic recrystallization, resulting in a peak microhardness of 189 HV. The FSW joint exhibited an ultimate tensile strength that was 80% of the AA7075 base alloy. Potentiodynamic polarization and electrochemical impedance spectroscopy indicated intermediate corrosion resistance of the WZ (icorr = 5.322 mA/cm²) compared with AA7075 (8.549 mA/cm²) and AA5083 (1.376 mA/cm²). These results demonstrate that appropriate control of FSW parameters enables simultaneous improvement in joint strength and corrosion resistance, confirming the suitability of AA7075 and AA5083 friction-stir-welded joints for marine and structural applications.