Effect of solidification conditions on morphology of eutectic Si in Al-15Si composites

In order to optimize the morphology of eutectic Si in squeezecast Al2O3f/Al-15Si composites, the dependence of eutectic Si and solidification conditions in the monolithic Al-15Si alloy and composite was investigated by using optical microscope and SEM techniques. The experimental results show that eutectic Si remains platelike in squeezecast and furnacecooled Al-15Si alloys, whereas eutectic Si changes from platelike to sticklike in Al2O3f/Al-15Si composites; fine modified, needlelike and sticklike eutectic Si could be obtained after Al2O3f/Al-15Si composites were waterquenched, moldcooled and furnacecooled after being remelted at 750 ℃; remelting and furnacecooling is one of the ways to optimize the microstructures of squeezecast composites.