The semi-solid slurry of AZ91D magnesium alloy was prepared by a novel self-inoculation method

and the role of fluid director in formation of non-dendritic microstructure in semi-solid slurry was described. The results show that temeprature of the alloy melt is decreased sharply to nearby liquidus as a result of absopting a lot of super-heat by fluid director after pouring alloy melt with inoculation tretament on fluid director. With melt flowing on the fluid driector

heterogeneous nucleation is promoted and a large amount of free grains are generated

resulting in a proliferation of grains density during solidification

so the microstructure of solid shell solidified on the fluid director surface is varied from developed dendritic to fine dendritic

and finally to equiaxed grain. The degree of slope angle has affected flow way and heat transfer effects. An excessively high or small angle is harmful to the proliferation of grain density

and the desirable cooling and shearing effect can be obtained with slope angle of 45°

where the number of efficient grains is the most and the microstructure of primary phase in semi-solid slurry presents small size and uniform distribution.