Density and solidification shrinkage of hypereutectic Al-Si alloys

The relationship between the density and temperature in hypereutectic Al-Si alloys was measured in the temperature range from 800 K to (T-1 + 30) K using the indirect Archimedean method. This method eliminates the effects of surface tension on the densities of salts and alloys and reduces the error in estimating the density and solidification shrinkage of Al-Si alloys. Eutectic LiCl-KCl salt was used as a reference liquid. The results indicate that the density vs. temperature curve has three transformation points: the liquidus temperature, eutectic transformation temperature and completely finished eutectic transformation temperature. The obtained densities of solid and liquid hypereutectic Al-Si alloys are in agreement with those reported in earlier investigations. The solidification shrinkage decreases from 2.5% for the Al-Si alloy containing 15% Si to -0.4% for the alloy with 25% Si.