Chemical modification of the morphology of the eutectic phases in hypoeutectic aluminum-silicon alloys

A mechanism is presented to explain the chemical modification of the morphology of the eutectic phases in Al-Si hypoeutectic alloys. The mechanism is supported with results of non-equilibrium thermal analyses, and microstructure evidence obtained from optical, scanning and transmission electron microscopy, as well as selected area electron diffraction analyses and results of high temperature rheological measurements all performed on Al-Si alloy samples of precisely controlled chemistry.