A fluidity model of semi-solid magnesium alloy was established based on the solidification theory. Filling behavior of the semi-solid AZ91D magnesium alloy was simulated by the model

which was well in agreement with experimental ones. The filling ability of the semi-solid alloy was tested by fluidity experiment. The results show that filling ability of the sheared semi-solid magnesium alloy slurry is greatly superior to that of un-sheared ones. Filling length of magnesium alloy slurry before and after shearing is firstly increased gradually and then decreased with decreasing in filling temperature. The maximum filling length of the semi-solid magnesium alloy slurry can be observed at filling temperature of 560

5

70℃.