Effects of welding physical fields on the microstructure evolution during dynamic-stationary shoulder friction stir welding

Abstract

Studying the physical fields in the friction stir welding (FSW) can reveal how they impact the microstructure of the joint, allowing one to develop more reliable joints. In this study, the Al–Cu dynamic-stationary shoulder friction stir welding (DSSFSW) was simulated using a three dimensional (3D) coupled Eulerian-Lagrangian finite element model to elucidate weld physical characteristics. The results revealed that the materials were mainly deposited in the areas between the weld centerline and the RS in DSSFSW. Compared with the bottom of the joint, the material flow velocity and range at the top region were higher, which leads to greater strain. The high strain prevented the growth of IMCs at the interface, therefore, the tensile strengths of the top and middle regions of the joint were significantly higher than those of the bottom. The above results verified the accuracy of the simulation.

Keywords

• Dynamic-stationary shoulder friction stir welding
• Numerical simulation
• Intermetallic compounds
• Material mixing
• Mechanical properties