Thermo-Mechanical Modeling of Friction Stir Welding of High Strength Aluminum Alloy 7075 T651

A finite-element-based three-dimensional thermo-mechanical model was investigated to predict the temperature distribution in tool and workpiece during friction stir welding (FSW) of AA7075 T651. ANSYS APDL had been used for this simulation. It was defined by four different load steps: plunge, dwell, traverse, and pull out of tool. Temperature-dependent friction coefficient between tool and workpiece was considered. The cooling effect caused by the free convection in ambient air, backing plate, and clamping bar has been taken into account. It was observed that the peak temperature of outside the shoulder region sharply reached its peak point and then decreased slowly, whereas the peak temperature within the shoulder region was dependent on shoulder diameter and welding speed. In addition, it is also observed that peak temperature during welding is not uniform due to temperature-dependent material properties.