As an important alloy widely used in the aerospace and automobile manufacturing industries, 2219 aluminium alloys are prone to hole shrinkage, second-phase aggregation, and macroscopic segregation of ingots produced under general gravity casting conditions. In this study, 2219 aluminium alloy ingots were prepared by combining the ultrasound-assisted treatment of melt and argon cooling under high-purity atmosphere protection. The effects of ultrasonication and argon cooling on the solidification structure and macroscopic segregation of 2219 aluminium alloy were studied by spectrometer, OM, SEM, etc. The experimental results show that under high-purity atmosphere protection, ultrasonication has a good effect on refining grains and homogenizing the second phase in 2219 aluminium casting, and there are no loose shrinkage defects in the microstructure. When ultrasonication and argon cooling are applied together, the grain refinement and second-phase homogenization of the ingot are improved, and the average grain size is reduced by 43.5%. Due to the cavitation effect of ultrasound, the nucleation of the melt is accelerated, promoting the solid solution of more solute elements in the aluminium matrix. At the same time, under the disturbance effect of cavitation fragmentation

and sound flow, the second phase structure is finer and more uniform, and the macroscopic segregation is greatly improved.