Modelling the effect of casting defects on tensile properties of high-pressure die-cast AlSi9Cu3(Fe) alloys

The effect of casting defects on mechanical properties of a high-pressure die-cast AlSi9Cu3(Fe) alloy is reported. A series of U-shaped structural components are cast using a combination of injection parameters and pouring temperatures in order to generate different types and amount of casting defects throughout the casting. It has been found that castings contain defects, primarily pores and oxides, and that the presence and distribution of these defects are highly sensitive to the process conditions. The tensile properties are affected by the amount and distribution of defects and are determined by the defect area fraction. The influence of casting defects on mechanical properties are investigated through a theoretical verification based on constitutive and stochastic models. The analytical approach, based on the Ghosh constitutive model of tension instability, correctly indicates the trends of the experimental results, while the Weibull statistics evidences how the scale parameter and the Weibull modulus are strongly affected by the casting conditions.