Based on numerical simulation methods

a two-dimensional electromagnetic field finite element model of aluminum alloy melt was established

and the effects of current mutation and different electromagnetic frequency on the magnetic induction intensity

electromagnetic force and primary phase of semi-solid aluminum alloy melt were investigated. The results reveal that under the same current mutation

the electromagnetic force and magnetic induction intensity are firstly increased and then decreased with the increase of the electromagnetic stirring frequency

reaching the maximum value at 25 Hz. Under the same electromagnetic frequency

the electromagnetic force and magnetic induction intensity are increased with the increase of the amplitude of current mutation

and the maximum value appears when current mutates from 2 A to 6 A. In the case of the optimal stirring frequency（25 Hz） and the mutation current（2～6 A）

the shape factor and average equal-area circle diameter of the primary phase are 0.71 and 118 μm

respectively.