Plastic deformation behavior of the friction stir welded AA2024 aluminum alloy

In order to study the effect of plastic deformation on the banded texture and flashes in friction stir welding process, a three-dimensional Lagrangian incremental finite element model was developed. The plastic deformation of friction stir welding and the forming and healing of transient keyhole during the welding process were studied visually by numerical simulation and validated by corresponding experiments. The simulation results were acceptably in good agreement with the experimental data. As shown in the numerical and experimental results, the flash of FSW joint which could be divided into two layers was mainly distributed on the retreating side. The forming and healing process of transient state keyhole includes outflow of weld materials from the beginning to 1/3 rotation period and backflow into the keyhole after 2/3 period. The distribution of plastic deformation was inhomogeneous upon the transverse cross-section, while the large deformation region was near the top surface and close to the advancing side.