Rapid Spheroidization Process of S Phase (Al₂CuMg) in the As-Cast 2024 Al Alloy Induced by High-Energy Electropulsing

The effect of electropulsing treatment (EPT) on the microstructure of the as-cast 2024 Al alloy at room temperature was investigated. The results show that EPT remarkably accelerated the spheroidizing of second phase (S phase) in the as-cast 2024 Al alloy. The mechanism for rapid spheroidizing of the second phase was proposed based on not only the accelerated dissolution, but also the growth of particles. The morphology and size of the secondary phase could be controlled by changing the cooling speed of the specimen after EPT. Furthermore, the dissolving process of the randomly distributed S phase was recognized as the combination effect of the two basic dissolving ways. Hence, the EPT can be applied to improve the microstructure and properties of the alloys.