MODELING THE FORMATION OF POROSITY DURING LOW PRESSURE DIE CASTING (LPDC) OF ALUMINUM ALLOY A356

摘要

In this study, the formation of macro and micro porosity during Low Pressure Die Casting (LPDC) of Aluminum alloy A356 has been modeled based on the solution of the heat conduction, continuity and Darcy equations. In this model a two-stage approach has been used to predict the formation of porosity. In the first stage, the evolution of porosity has been determined based on the partitioning of hydrogen between solid, liquid and pore, whereas, in the second stage, when the calculated pressures reach the vapor pressure of the liquid, the evolution of porosity is calculated based on the volume of isolated liquid. By studying the role of permeability as the critical factor in determining the local pressures, the feed-ability of the mushy zone has been assessed. In order to validate the current method, the model has been applied to examine the evolution of pores in a trial casting.