Effects of twin-screw structure on the microstructure of semi-solid Mg alloy slurry have been investigated

meanwhile

comparison between effects of twin-screw and of single-screw has been conducted. Experimental results indicate that fine spheroidized structure with average diameter of 40

6

0 μm in the slurry can be prepared by both combination twin-screw stirring and single screw thread twin-screw with high shearing rate

where the range of solid fraction can be controlled from 15% to 60%. However

compared with single screw thread twin-screw structure

the combined twin-screw structure can take more stirring effects due to the delivery

shearing

mixing mechanism

strengthening homogenization of the melt and shearing effects

thus the structure of semi-solid magnesium with finer and more round can be obtained. In contrast

because of the weak effects of mixture with low shearing rate

the solidified microstructure of the slurry prepared by single screw is strip shape or anomalous block with the primary grain size in the range of 60

8

0 μm.