Effect of damage evolution of Si particles on the variability of the tensile ductility of squeeze-cast Al-10%Si-2%Cu-0.4%Mg alloy

The variability in the tensile elongation of squeeze-cast Al-10%Si-2%Cu-0.4%Mg alloy was investigated in terms of the defect susceptibility to the effective void area fraction, which is the sum of the additional void area caused by damage evolution of eutectic Si particles and the void area of pre-existing microvoids. Additional theoretical verification was performed by constitutive prediction. The tensile elongation of as-cast and T6-treated alloys is described as a power law relationship to the variation of the effective void area fraction. The anisotropic fracture damage of eutectic Si particles has a significant contribution to the total effective void area fraction when compared with the variation of load-bearing capacity by microporosity. The constitutive model can precisely predict the defect susceptibility of tensile elongation to the variation of effective void area fraction. Additionally, the model suggests that the tensile deformation of Al-10%Si-2%Cu-0.4%Mg alloy is affected by the maximum effective void area, which corresponds with extremes of the distribution frequency, rather than the average value of the microstructural characteristics, especially over a wide-range distribution of aspect ratio of Si particles.