Application of a time-dependent constitutive model to rheocast systems

A mathematical model has been developed to describe the velocity field in an agitated Al-5Cu alloy in which B sub 4 C particles were suspended at different loading rates of up to 40%. The material system was agitated by means of an electromagnetic rotary stirrer. The non-Newtonian behavior of the melt/solid slurry was allowed for using two models: the steady-state model of Joly and Flemings and the model of Brown, which takes account of time-dependent behavior. Calculations have shown that the two models behave similarly at high shear rates. In addition, if agitation was discontinued, very little time was required for the velocity (and hence the fluidity) of the slurry to decay.