Density and solidification shrinkage of hypoeutectic aluminum-silicon alloys

The density of liquid and solid hypoeutectic aluminum-silicon alloys has been measured with high accuracy in the temperature range 400 °C to 800 °C by using the indirect Archimedian method. A eutectic mixture of KCl and LiCl salts was used as reference liquid. This method allowed measurements of density for both liquid and solid in the same experiment and thus reduced the systematic error in estimating the solidification shrinkage. The results show that the density of liquid aluminum-silicon alloy increases with increasing silicon content, while silicon reduces the density in the solid state. Silicon content reduces the solidification shrinkage from 6.6 pct for pure aluminum to 4.4 pct for Al-11.6 pct Si.