Effect of Rectangle Wave Pulse Current on Solidification Structure of ZA27 Alloy

1 IntroductionPrevious study showed that imposed pulse currentcould present apparentlyfavorable actions to solidificationprocessing and microstructure of alloys1-9]. However ,themechanismof inoculation and modification by pulse cur-rent during solidificationis not resolved yet .The solidifi-cation system of alloys is open. The characteristics offluctuating and oscillating in melt are emerged with thelapse of time during solidification. The employed pulsecurrent by most researchers was genera…

Effect of rectangle wave pulse current on solidification structure of ZA27 alloy

The effect of rectangle wave pulse current on solidification structure of ZA27 alloy was studied. The restdts show that the wave pattern relies on the frequency range of harmonic wave and the energy of pulse current within the frequency range of pulse current. Imposed pulse current could induce the solidification system to oscillate. The frequency range and the relevant energy distribution of pulse current exert an influence on the amount of atoms involved for forming critical nucleus, the surface states of dusters in melt, the oscillating state of melt on the surface of dusters, the active energy of atom diffusion , the frequnce response of the resonance of bulk melt and the absorbability of the solidification system to the external work. Rectangle wave pulse current involves rich harmonic waves ; the amplitudes of high order of harmonic waves are higher and reduce slowly, so it has a better effect on inoculation and modification.