Effect of Ultrasonic Treatment on the Eutectic Phase and Cu Content in the Al Matrix of Large-Scale 2219 Al Alloy Ingot

The modification of coarsening eutectic phase is particularly important for the performance of large-scale ingot. In this study, the area fraction of coarsening eutectic phase and the Cu content in the Al matrix were compared between ingots with and without ultrasonic treatment. The morphology of the eutectic phase was investigated by SEM. Optical emission spectroscopy was used to determine the macroscopic Cu content and EPMA was applied to detect the Cu content in the Al matrix. Results showed that Cu atoms distributed more uniformly along the radius of the ingot after ultrasonic treatment. Meanwhile, the higher area fraction of coarsening eutectic phase usually leaded to lower Cu content in the Al matrix, which could decrease the solubility of Cu and deteriorate the mechanical performance of the large-scale ingots, while this phenomenon was ameliorated in the ingot with ultrasonic treatment.