Grain Refinement and Eutectic Solidification Mechanism of Al-Si Hypoeutectic Alloy in Centrifugal Casting with Electromagnetic Field

摘要

A series of Al-Si hypoeutectic alloy ingots were prepared by centrifugal casting (CC) both with and without an external electromagnetic field (EMF). The effects the EMF on grain refinement and on the solidification mechanism during centrifugal casting have been investigated using optical microscopy, scanning electron microscopy (SEM) and electron backscattering diffraction (EBSD) orientation measurements. The electromagnetic stirring effect caused by the EMF promotes the columnar-equiaxed transition (CET) resulting in a finer cast grain size. The silicon and aluminum nucleate and grow independently both with and without EMF.