Modeling of porosity in aluminum alloy castings

As part of a program to develop codes for the prediction of microporosity in cast lightweight automotive structural parts, permeability measurements have been conducted on aluminum-4.5% copper alloy and the measured permeabilities have been related to the solidification microstructure. A comprehensive methodology taking into account mold filling, solidification, shrinkage-driven interdendritic fluid flow, hydrogen precipitation, and porosity evolution has been developed for the prediction of microporosity and macroporosity. Microporosity distributions have also been experimentally determined for plate and bar castings of aluminum-4.5% copper alloy over a wide range of solidification conditions. These experimentally determined porosity distributions are correlated to results from the computer model. Based on these results, the model will be used to predict porosity distributions in a complex shaped casting.