Solidification of hypoeutectic aluminium - silicon alloys

The traditional approach to solidification considers nucleation, dendritic growth, interdendritic feeding and eutectic solidification largely as discrete events. However, in an actual casting there is a complex interaction between these events with considerable flow of liquid and solid crystals occurring during solidification. In order to properly control the formation of casting defects it is shown that a better understanding of the phase transformation mechanisms is necessary as they directly control the response of the solidifying mush to the stresses and pressure gradients developed during solidification or imposed by the casting process. The latest advances in developing this understanding are presented. Implications of this new understanding are also outlined