A die-casting method and a device (10) for use in the die-casting method are disclosed. The casting material, which can be liquid metal, semi-solid metal or metal-matrix composite, in the shot chamber (12) of a die-casting machine (10), is driven to flow with high shear rate to mix homogeneously by the electromotive force induced with at least one low-frequency shifting electromagnetic field. The temperature and the microstructure of the casting material near the shot chamber (12) are further controlled and perturbed by at least one high-frequency electromagnetic field to minimize the temperature difference or the growth of dendritic microstructure. To ensure the efficiency of the electromagnetic fields, the shot chamber (12) is made of non-magnetic material and its wall thickness is less than three times the penetration depth of the electromagnetic fields. The shot chamber (12) is surrounded by at least one solenoid coil (24), a conducting shield (26), and at least one electric motor stator (20). The conducting shield (26), which only allows the low-frequency electromagnetic field to penetrate, protects the stator (20) from being overheated by the high-frequency electromagnetic field.