Efficient Melt Stirring Using Pulse Sequences of a Rotating Magnetic Field: Part II. Application to Solidification of Al-Si Alloys

The present study considers the solidification of an Al-7 wt pct Si alloy under the influence of electromagnetic melt stirring using a rotating magnetic field (RMF). The effect of a continuously applied RMF is compared with an RMF pulse sequence of alternating direction (RMF-PSAD). The resulting flow structure in a cylindrical liquid metal column has been measured by isothermal experiments using the ternary alloy GaInSn. The solidification experiments performed with the Al-7 wt pct Si alloy confirm our numerical predictions concerning the temperature field during solidification and the distribution of primary crystals and eutectic phase in the solidified samples. The application of the RMF-PSAD regime at suitable frequencies of the reversals of the magnetic field direction fP delivers an equiaxed microstructure without macrosegregation.

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