Mechanical behavior of aluminum matrix composite during extrusion in the semisolid state

Semisolid extrusion experiments have been carried out on SiC particle reinf orced aluminum composite. Different die diameters and ram velocities have b een used in order to obtain a range of extrusion conditions at a constant t emperature of 580 degrees C. The experimental results were fitted to a mult iple linear regression to obtain a constitutive equation describing the beh avior of the material in these conditions. From the regression equation, it was possible to model the material by finite element analysis. The predict ed values of the extrusion force resulting from the numerical analysis are consistent with the experimental values for the different conditions. The f low of primary phase particles through the die observed on micrographs has been compared with the predicted pattern and shows good agreement. These re sults also justify the use of a frictional stress factor corresponding to a sticking condition at the interface between the billet and the die compone nts.