A novel extension of the cellular automata technique for microstructural modelling is presented, allowing simulation of the evolution of the complex three-dimensional morphology of porosity during the solidification of an aluminiumsilicon alloy. The complex morphology arises due to the restriction of the growth of the pores by the developing solid phase. The model predicts the average properties of the porosity formed, together with the distribution in size and morphology.
The model is used to determine the influence of a variety of applied conditions (e.g. thermal history, pressure, hydrogen content) and material properties (nucleation behaviour, alloy composition) upon the pore morphology, as characterized by the average and extreme dimensions. The relative magnitude of the effect of each parameter and the interactions between parameters upon the porosity are statistically analysed. The simulated pore size shows the largest sensitivity to applied pressure, hydrogen content and solidification time, together with interactions between solidification time and pressure. These results are in good agreement with previously reported experimental behaviour.