Effects of different pulsed voltage and pulsed frequency on distribution and morphology of primary silicon in Al-20Si alloy were investigated.The results show that primary silicon mainly presents segregation and coarsening under pulsed magnetic field

which provides possibility for the preparation of gradient materials.When the pulse voltage is 80 V

the primary silicon is coarsened with segregation

which is concentrated in the edge not in the core position.With the pulsed voltage of 160 V

primary silicon tends to be coarsened and agglomeration

however the whole distribution tends to be uniform.When the pulse voltage is 240 V

the agglomeration and coarseness of primary silicon is weakened with more uniform distribution.When the pulsed frequency is 1

5

Hz

the distribution and morphology of primary silicon will be independent on the increase of the pulse frequency.However

when the pulse frequency is increased to 10 Hz

the primary silicon presents segregation and coarsening effects.