Effects of mould vibration on the microstructure and mechanical properties of a hypereutectic Al-Si alloy

Abstract

The effect of mechanical vibration during the solidification of hypereutectic Al-Si (Al-20% wt Si) alloy on the microstructure and mechanical properties was investigated. The specimen with a specification of 25 mm in diameter and 65 mm long were solidified in the frequency range of 0 to 6.3 Hz so as to examine the effect of the vibration on the grain structure, tensile strength, hardness value and impact energy. In comparison with the grains formed in the as-cast state without vibration, the morphology of the grains changes from predominantly dendritic to a more globular structure as the intensity of vibration increases. The test result shows that there is an improvement in the mechanical properties of the samples within the frequency threshold of 1.5 and 4.2 Hz.