Evaluation of solid fraction in a rheocast aluminum die casting alloy by a rapid quenching method

A new approach to evaluate the solid fraction of semi-solid slurries is reported. The approach applies a thin-channel vacuum mold to rapidly quench semi-solid slurries at different rheocasting times. The slurry temperatures are analyzed from the cooling curves. The corresponding solid fraction data are obtained from standard quantitative metallography. A correction of the data is then conducted using the average growth layer of the solid particles. The analyzed solid fraction agrees well with the data from the Scheil model.