Microstructural formation in hypereutectic Al-Mg2Si with extra Si

In the present work, the microstructure and the solidification process of an ingot metallurgy hypereutectic Al-Mg2Si alloy with extra Si were studied. Primary Mg2Si phase is surrounded by Al-Mg2Si binary eutectic and then by Al-Mg2Si-Si ternary eutectic structure. Primary Mg2Si phase at the centers shows dendritic or polyhedral morphologies. Al-Mg2Si binary eutectic cells with regular morphologies have flake-like Mg2Si surrounded by alpha-Al. Al-Mg2Si-Si ternary eutectic cells distribute among binary eutectic cells and make binary eutectic cells separated to be relatively independent islands. (C) 2008 Elsevier B.V. All rights reserved.