Rheological behavior of za27 alloy semi-solid slurries and Al2O3 particulate / ZA27 composite slurries

Abstract

The rheology of Al2O3 particulate/ZA27 composite slurries has been investigated and compared with that of the matrix ZA27 alloy. The influence of processing variables on the rheological behavior of semi-solid mixtures (SSMs) was examined. The mixing power change of SSMs was determined by the "electric method“ in the temperature range from 479 to 440˚C, at constant cooling rate. Mixing of ZA27 alloy SSM was carried out using cylindrical stirrer and paddle stirrer, while SSMs of composites were mixed using paddle stirrer only. On the basis of experimental measurements the values of the most important rheological parameters (apparent viscosity and shear rate) were calculated. It was noticed that apparent viscosity of SSMs of composites containing small Al2O3 particles is higher comparing to that of composites with large Al2O3 particles.