Numerical modeling of dynamic heat flow behaviour during friction stir welding of Al-Cu alloy

2219 Al-Cu alloy gained significance in various industrial applications, particularly in the aerospace, automotive, and marine sectors, where high strength-to-weight ratio is crucial. Friction stir welding (FSW) technology subsequently emerged as a prospective joining method, which could potentially address the limitations of conventional fusion welding processes. Present study was aimed at thermal modeling and numerical analysis of dynamic heat flow behaviour, for FSW joint of 2219 Al-Cu alloy, further supported and corelated with the experimental temperature profiles. FSW was performed on cast 2219 Al-Cu alloy, with varying welding process parameters of welding speed and rotational speed of the tool, and with transient temperatures measured at different distances from the weld line. To investigate transient temperature profiles over the welded plate, a 3-D Finite Element (FE) thermal model was developed, using the APDL code in ANSYS platform. The FEM model incorporated a volumetric heat source as heat generation, considering temperature-dependent properties. Transient temperature profiles computed from FEM analysis, were successfully corelated and compared with experimental results, with fairly good accuracy within 4.86%, validating the present numerical model. The individual influences of welding speed and rotational speed of the tool were analysed, on the dynamics of heat flow, transient temperature profile, peak temperature, cooling rate and formation of different weld zones. Through such thermal modeling and analysis, finally the welding parameters may be optimized, and temperature distribution may be predicted, which is the principal indicator of residual stress and grain growth, ensuring high-quality welds with minimal defects.