Effects of alternating electromagnetic field on flow characteristics and microstructure of semisolid A356 alloy which was prepared by cooling slope method in a inclined tube with inner diameter in80mm×550mm was investigated by an induction field in the metal liquid as a result of the alternating electromagnetic field utilizing to mix the metal liquid.The results show that

the Lorentz force can compel the flow of metal liquid from straight line to sine curve

and the non-homogeneous nucleation of the tube wall is enhanced

meanwhile

nucleation rate of the first eutectic phase is increased significantly.While the magnetic field can enhance the convection inside the metal liquid

and restrain deep undercooling and large temperature gradient of the metal liquid

thus it can inhibit preference growth of the first eutectic phase.Under electromagnetic field

the first eutectic phase is refined and spheroidized obviously

and homogeneity of structure is improved significantly.