Simulation of strain rate, material flow, and nugget shape during dissimilar friction stir welding of AA6061 aluminum alloy and Al-Mg2Si composite

A three-dimensional model was developed based on computational fluid dynamics (CFD) to study the visco-plastic material flow during friction stir welding of AA6061 aluminum alloy and Al-Mg2Si composite dissimilar joint. To model the dissimilar joint, the volume of fluid (VOF) method was used. The volumetric equation was defined for the heat which generated through the viscous dissipation. The model was investigated for three rotational speeds of 720, 920 and 1120 rpm. The nugget shape was in good agreement with the corresponding experimental results. The results showed that maximum velocity and strain rate occurred at the top surface of the workpiece and outer edge of the shoulder. Also, peak temperature was obtained at the advancing side. The strain rate at the advancing side and the retreating side was about 975s(-1) and 926s(-1), respectively. In a region of the stir zone where material mixing is dominant, the volume fraction of the AA6061 aluminum alloy is 0.4-0.8. (C) 2018 Elsevier B.V. All rights reserved.