Correlation Between Mechanical Properties and Porosity Distribution of A356 in Gravity Die Casting and Low Pressure Die Casting

Gravity die casting (GDC) and low pressure die casting (LPDC) methods were used to compare the mechanical properties and porosity distribution in a 5-step mould design. Commercially available A356 alloy was used for the experiments. Ar and Ar+H₂ mixture were used to achieve two different hydrogen levels, i.e. 0,1 and 0,2 ml/100g Al, respectively. Although the porosity level was lower in LPDC, the tensile properties were lower than GDC due to the fact that LPDC melt had 50 mm bifilm index, whereas GDC melt had 20 mm. This investigation has shown that the metal quality has a larger effect over the mechanical properties than the porosity content.