Viscosity of semi-solid A357 alloy in the transient high shear rate regime

Abstract

A modified, parallel-plate rheometer is described for measuring the viscosity of semi-solid slurries under isothermal or continuous cooling conditions at shear rates up to 2000 s-1 and under transient conditions. The shear rate is rapidly changed by varying either the rotation speed of the plate or the gap between the plates. Shear rates changes of up to 1500 s-2 are obtainable. The semi-solid slurries studied are prepared by reheating rheocast material of industrial origin into the semi-solid range.

Viscosity measurements under conditions of constant and abruptly changing shear rate will be presented and related to structural studies.