Experimental and theoretical evaluations of thermal histories and residual stresses in dissimilar friction stir welding of AA5086-AA6061

In this work, the thermomechanical responses during the dissimilar friction stir welding of aluminum alloys have been evaluated employing a three-dimensional model and the finite element software ABAQUS. Furthermore, welding experiments have been conducted under different working conditions and the temperature variations during and after welding as well as the produced residual stresses in various positions of the welded samples were measured using hole-drilling technique. The model results were then examined by experimental data, and a reasonable agreement was observed. It is found that tool rotational speed significantly affects the amount of maximum tensile residual stress while traverse speed mainly changes the distribution of transverse residual stresses. Also, both experimental and simulated results indicate that welding fixtures significantly affect the residual stress profiles as well as their magnitudes.