Large-size aluminum alloy ingots produced by traditional direct chill (DC) casting, especially the 2xxx and 7xxx series, often have defects such as inhomogeneous structure, macrosegregation, and hot cracks [1][2][3][4] . Although adding grain refiners improves the quality of largesize ingots, it could lead to agglomeration of nucleating particles and fading effect [5][6] . In addition, physical methods, including mechanical stirring [7][8] , ultrasonic vibration [9] , and electromagnetic stirring [10] , are not easy to apply in the DC casting process because of the expensive and specific equipment requirements.Recently, several new methods have been developed by adding intercooling in the DC casting process. For instance, an in-mold cooler with a cooling end made of highly pure graphite can be inserted into the melt to absorb and transfer the heat during the liquid or gas flow in the cooler [11][12] . Another way to enhance