RARE METALS, vol.41, no.8, pp.2767-2776, 2022 (SCI-Expanded)
The effect of Mg2Si amount on the properties of Al-Mg2Si as-cast composites was investigated in this study. Composites with different amounts of Mg2Si (15 wt%, 20 wt% and 25 wt%) were fabricated, and the fluidity, viscosity, porosity formation and tensile properties were then analyzed. In addition, optical microscope and scanning electron microscope were used for microstructural studies and fractography. The results reveal that with the amount of Mg2Si increasing, the morphology of the primary Mg2Si becomes irregular, the size of primary Mg2Si increases, fluidity decreases, viscosity increases, and porosity amount increases. The reason for the higher amounts of porosities is the lower fluidity and higher viscosity. In addition, Al-15% Mg2Si shows better tensile properties and higher quality index compared to other composites. Furthermore, the fracture surface of the composite with lower Mg2Si amount reveals more ductile mode than those with higher Mg2Si amount.