Numerical Investigation of Thermomechanical Behavior and Microstructural Evolution in Friction Stir Welded 6061 Aluminum Alloy

This investigation scrutinized the thermomechanical behavior and microstructural evolution within the friction stir weld zone by employing an integrated approach that amalgamated numerical modeling and experimental validation.A new friction stir welding tool was utilized during the welding process, distinguished by a stirring pin with helical features and a shoulder surface with annular grooves.The study systematically assessed the friction stir welding process of 6061 aluminum alloy with parametric variations in spindle speed (600-1000 rpm) and welding speed (80-120 mm/min).A coupled Eulerian-Lagrangian finite element model was developed to characterize thermoplastic deformation within the weld zone, whereas microstructural evolution was analyzed utilizing a time-dependent grain evolution model implemented through Monte Carlo simulation.The model predictions exhibited a strong correlation with experimental observations, corroborating its capability to accurately characterize the concurrent evolution of grain morphology within the weld nugget.