Graded distribution and refinement of Mg2Si in Al–Mg2Si alloy prepared by traveling magnetic field

To quantitatively analyze the mechanisms of graded distribution and refinement of electromagnetic separation technology, in situ Al–Mg2Si graded materials were prepared using traveling magnetic field. Simulation and experiment were both carried out to analyze the effect of traveling magnetic field on the distribution and size of Mg2Si phase. Simulation results show that 6A excitation current density achieves the best effect of graded distribution. Experiments results show traveling magnetic field changed the distribution of Mg2Si in the alloy from uniform to graded distribution and refined the size of primary Mg2Si particle from 16 μm to 10 μm at the outer region on the cross-section. The mechanism of refinement was quantitatively analyzed, the refinement of Mg2Si particle results from stirring and crushing by magnetic field without promoting nucleation. The graded distribution mechanism is attribute to the resultant force acting on Mg2Si particle, which promote Mg2Si particle distributed near the outer region and graded distribution. Hardness distribution on the cross-section is consistent with the volume fraction distribution of Mg2Si.