A Steady State Model for the Rheological Behavior of Semisolid Al-6.5wt%Si Alloy
In the present work, The Chen and Fan (CF) model [1] of semisolid metal slurries (SSMS) is improved by modifying the expression of the packing parameter, of the solid particles and then the modified CF (MCF) model is obtained. Subsequently, the MCF model is applied to the Al-6.5wt%Si alloy to investigate its rheological behavior at steady state. The factors which affect the steady state behavior have been studied. It has been shown that the steady state viscosity and the average agglomerate size increase with increasing the solid volume fraction and decreasing the shear rate. The prediction of the model is in good agreement with the experimental results in the literatures qualitatively. The importance of the effective solid volume fraction is shown by explaining the strong coupling between the viscosity and the microstructure. The external flow conditions such as shear rate etc change the agglomeration degree, that is, the effective solid volume fraction and then the viscosity