Process analysis and multi-parameter optimization of 5052 aluminum alloy FSW based on thermo-mechanical coupling and Taguchi method.

Based on the Johnson-Cook constitutive model and modified Coulomb's law, the study investigates the impact of various process parameters on the weld temperature field in high-strength 5052 aluminum alloy friction stir welding (FSW) for aerospace applications. Utilizing a thermo-mechanical model, the significance of rotational speed, welding speed, and indentation on the peak weld temperature is examined through Taguchi's orthogonal experimental design. S/N ratio and ANOVA results show that the rotational speed has the most significant effect on the peak temperature of the weld, followed by the amount of indentation, and the welding speed has the smallest effect, the optimal combination of welding process parameters is determined as follows:the rotational speed is 1000 rpm, the amount of indentation is 0.15 mm, and the welding speed is 1 mm/s, the ultimate tensile strength of welded joints under the parameter combination is increased by more than 40%relative to the base material, and the yield strength is increased by 113.5%. The experimental results show that the worst combination of welding process parameters, there are tunnel-type defects, the tensile fracture surface has a large number of relatively large and deep tough nests, and compared with the optimal combination of process parameters, the combination of fracture position of the Si element content is higher, its UTS is only 85.2%of the base material, much lower than the optimal parameters under the performance of the strength. The above conclusions demonstrate the robustness of the optimization method and provide an important reference for improving the quality of FSW joints.