Abstract: Effect of rectangle wave pulse current on solidification of ZA27 alloy is studied. The results show that the wave pattern of pulse current determines on the frequency range of harmonic wave and the distribution of energy of pulse current among the frequency range. Imposed pulse current could induce the solidification system to oscillate. The frequency range and the relevant energy distribution of pulse current exert influence on the amount of atoms involved for forming critical nucleus, the surface states of clusters in melt, the oscillating state of melt on the surface of clusters, the active energy of atom diffusion, the frequency response of the resonance of bulk melt and the absorbability of the solidification system to the external work. Rectangle wave pulse current involves in rich harmonic waves, the amplitudes of induced oscillation of high order of harmonic waves are higher and reduce slowly, so it has better effect on inoculation and modification.

Key words: Harmonic wave, Oscillating, Rectangle wave pulse current, Solidification structure, ZA27 alloy