Effect of electromagnetic stirring during solidification on the morphological evolution of primary solid phase of Al alloy

Abstract

In this study, in order to develop the cast product of Al alloy having a globular microstructure by using the elctromagnetic (EM) stirrer, which was specially designed and manufactured to induce a various fluid flow type of melt during solidification, a morphlogy and size of primary solid phase of the solidifying slurry was investigated with respect to EM stirring condition such as an induced magnetic flux density (MFD) and a frequency of input current. The magnetic flux density of EM stirrer was measured by using a gaussmeter and its distribution and magnetic force within Al melt was simulated in ANSYS program. The induced MFD was increased with decreasing a frequency of input current at the same input voltage due to the increased penetrating depth of magnetic field. But, the magnetic force related directly with a stirring strength of melt was increased with the frequency. Both a roundness and size of primary a phase of Al alloy was decreased with increasing a frequency of input current and MFD, within the experimental range. Therefore, the primary a phase was refined and globularized at the higher frequency and MFD.