A comprehensive review of progressive developments and challenges in dissimilar welding of aluminum and magnesium alloy by friction stir welding

Friction stir welding has emerged as a promising solid state joining technique for aluminum-magnesium alloys, widely used in autmotive, aerospace, and marine industries due to their excellent corrosion and strength-to-weight ratio. This review critically examines the mechanical properties, microstructural evolution of the welded joints. The novelty of this review is the correlation between grain refinement, welding parameters, and tool geometry on microstructural control. Despite these advantages, studies have reported the occurrence of intermetallic compound (IMCs) in FSW of Mg-Al joints, welding parameters, and input heat influence their amount and thickness. It underscores the importance of optimizing weld parameters to minimize the adverse effect of IMCs. While various interfaces in butt joints have been explored, the mechanism of interfacial interaction and ways to enhance joint quality have not been extensively reviewed. The objective of this review paper is to fill that gap by analyzing past research on microstructure interface evolution, joint mechanism, and welding parameters. It was observed that most research has focused on the structural morphology, technological feasibility, and mechanical properties of Al/Mg weldments, with limited attention to environmental degradation and operational failure. Future research must focus on developing strategies for IMC formation, optimizing welding parameters, and enhancing joint efficiency for reliable and sustainable use in industrial applications.