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A methodology that includes the processing history of the metal in the High Pressure Die Casting (HPDC) process in the simulations of the structural behavior of magnesium components has been established. In this methodology the results from the HPDC process simulations are used to modify the material model and the fracture criterion in the Finite Element Analysis (FEA). This paper focuses on the simulation of the HPDC process for thin-walled magnesium components. The close connection between the processing history and the mechanical properties of the casting mandates a careful analysis of the key factors influencing the final part performance. The definition of the boundary and initial conditions will strongly influence the ability to predict important features in the microstructure of the casting and consequently the final mechanical properties of the casting.

High pressure die casting is characterized by rapid die filling and subsequent rapid cooling of the molten metal in the die. These characteristics are favourable for magnesium die casting alloys. The high cooling rate favours the formation of a fine dendrite and grain structure, which in turn leads to substantial hardening; this refinement also provides improved ductility. Since the cooling rate of the metal is highly dependent on both the process parameters and the geometry of the part, the three-dimensional flexibility associated with the latter factor means that the cooling rate cannot be uniform. This cooling rate difference in turn can lead to some variation in the mechanical properties between geometrically different portions of a die cast component. This variation is an inherent property of the material, in contrast to casting defects like microporosity, non-metallic inclusions, filling defects, and formation of hot cracks.