Research progress on semi-continuous casting of magnesium alloys under external field

High-performance magnesium alloys are moving towards a trend of being produced on a large scale and in an integrated manner. The foundational key to their successful production is the high-quality cast ingots. Magnesium alloys produced through the conventional semi-continuous casting process inevitably contain casting defects, which makes it challenging to manufacture high-quality ingots. The integration of external field assisted controlled solidification technology, which combines physical fields such as electromagnetic and ultrasonic fields with traditional semi-continuous casting processes, enables the production of high-quality magnesium alloy ingots characterized by a homogeneous microstructure and absence of cracks. This article mainly summarizes the technical principles of those external field assisted casting process. The focus is on elaborating the refinement mechanism of different types of electromagnetic fields, ultrasonic fields, and combined physical fields during the solidification of magnesium alloys. Finally, the development prospects of producing high-quality magnesium alloy ingots through semi-continuous casting under the external field were discussed.