A Modeling and Experimental Investigation on the Formation of Acicular Silicon and Sludge in High Pressure Die Casting of a Modified A383 Alloy

摘要

A numerical model is being developed to predict the formation of sludge (e.g., Fe-containing intermetallic compounds) and acicular silicon during high pressure die casting (HPDC) of a modified aluminium A383 alloy. The iron-rich sludge-phase and silicon rich phases with needle-like morphology play a major detrimental role in the mechanical properties, especially the fracture characteristics, of high pressure die cast engine components. The modelling approach consists of using a macroscopic fluid flow, heat transfer and solidification model to predict the cooling rates in the HPDC A383 process. The results are being compared against experimental measurements (e.g., amount, type and size of detrimental phases) in A383 samples extracted from various regions of an HPDC engine block. The approach can be applied to predict the effects of cooling rate on the final phase microstructure.