Friction Stir Welding of Non-Heat Treatable Al Alloys: Challenges and Improvements Opportunities

Friction stir welding (FSW) is an effective solid-state joining process that has the potential to overcome common problems correlated with conventional fusion processes. FSW used for of metallic materials, in particular Al alloys (non-heat-treatable and heat-treatable). The heat produced by friction between rotating tool workpiece material generates a softened region near tool. Although input plays crucial role producing defect-free weld metal, it serious concern work-hardened non-heat-treatable alloys. In this group alloys, mechanical properties, including hardness, tensile fatigue life, are adversely affected softening effect because grain growth reduced dislocation density. Considering challenge, have been limited their industrial use, which includes aerospace, shipbuilding, automotive, railway industries. current comprehensive review presents various approaches available studies improving quality joints expanding use. First, optimization parameters, rotational traverse speeds, design, plunge depth, tilt angle discussed. Second, incorporation reinforcement particles then underwater stated as other strategies strengthen joint. Finally, some supplementary techniques containing surface modification, bobbin FSW, copper backing, double-sided relation strain-hardened considered.