Research on the synergistic regulation of weld formation and multiple performance parameters in ultrasonic-assisted TIG welding of 2219 aluminum alloy thick plates

To address the issues of significant deformation, high residual stress, and poor joint performance in the conventional welding process of 2219 aluminum alloy, this paper constructs an ultrasonic-assisted TIG welding system. This system employs high-frequency ultrasonic excitation coupled with the welding process to improve the microstructure and enhance the overall mechanical properties. By utilizing a variety of characterization techniques, such as x-ray, three-dimensional deformation measurement, ultrasonic stress measurement, microstructure observation, and mechanical property testing, we systematically analyze the influence patterns of acoustic energy input on the microstructure and macroscopic properties of welded joints. The results revealed that, in comparison with conventional TIG welding, the ultrasonic-assisted welding process reduces component deformation. It increases the tensile strength of the joint by ∼34%, improves elongation by 68%, and enhances the impact toughness of the weld zone (WZ) and heat-affected zone (HAZ) by 14% and 36%, respectively. Moreover, it decreases the peak residual stress by around 35%, improves corrosion resistance, and raises the average microhardness by ∼10%. This study offers a theoretical foundation and technical approach for ultrasonic welding of aluminum alloy thick plates, expanding the engineering application potential of ultrasonic technology in high-end manufacturing sectors.