THERMOMECHANICAL MODELING OF SOLIDIFICATION PROCESS OF SQUEEZE CASTING I. Mathematic Model and Solution Methodology

A coupled thermomechanical finite element model has been developed to simulate the temperature, stress and shape developments during the solidification process of squeeze casting. The model includes the effect of latent heat and volume shrinkage due to solidification, the mutual dependence of interfacial heat transfer and casting deformation, and the mechanical behavior of the solidified shell under the punch pressure. The stress model features a thermo--elasto--viscoplastic constitutive equation that accounts for the response of the solidified shell as well as a special treatment given to the liquid and mushy zones. A contact algorithm was employed for the casting/die interface, and an iterative algorithm was employed to simulate the movement of the punch. The model can be used to investigate the effects of die design and process parameters (die temperature, punch pressure, etc.) on the quality of castings.