Degassing effect and grain refinement of Al-Si alloy under ultrasound field

Abstract

Under different constant temperatures a Al-1%Si alloy (mass fraction) melt was treated by ultrasound field. The gas content in Al-Si melt decreased obviously when the treated time is 60 s. The grains are refined and globularization when the Al-Si melt was solidified under ultrasound but the grains only are refined when solidified at isothermal temperature in the mushy zone with ultrasonic vibrations. The results imply that the expansion and collapse of cavities which results in the formation of nuclei play the important role in the formation of fine and globular grains