Formation of non-dendritic microstructure of semi-solid aluminum alloy under vibration

A new technique of introducing mechanical vibration during isothermal holding period of hypoeutectic Al–Si alloy to prepare semi-solid slurry has been studied. The convection of melt caused by vibration had notable effects on the formation of near-spherical primary Al particles. When the vibrating frequency increased from 11.7 to 33.3 Hz, the average diameter of non-dendritic primary particles decreased from 125 to 90 μm, and the average shape coefficient increased from 0.40 to 0.55.