Numerical simulation and experimental research on friction stir welding of 2024-T3 aeronautical aluminum alloy

2024-T3 aeronautical aluminum alloy is a high-strength hard aluminum alloy, belonging to the Al-Cu-Mg series. It is mainly used for manufacturing various high-load mechanical parts such as aircraft skeletons. 2024-T3 aluminum alloy is difficult to be welded with traditional fusion welding, especially welded with another material such as titanium alloy or copper alloy. The welding quality of 2024-T3 aluminum alloy can be improved effectively by friction stir welding, which is favored in the aerospace and shipbuilding fields. Accurately grasping the welding transient evolution mechanism is the key to improving welding quality. It plays an important role in promoting the application of friction stir welding in industry. In this paper, the material physical parameters that change with the temperature were calculated by using the CALPHAD method, and the numerical model for friction stir welding was established. The transient changes in the temperature and stress field of the workpiece and the load of the stirring head were obtained. The temperature, stress, and strain of the advancing side and retreating side were compared and analyzed. The temperature of the workpiece surface and the stress around the keyhole were revealed. Zeiss Sigma 500 field emission scanning electron microscope was used to perform micro-characterization experiments, and the accuracy of the model was verified by comparing the simulation with the experiment. This research is of considerable significance for accurately revealing the mechanism of friction stir welding.