Abstract
To study the effect of alternating electromagnetic force on the refinement of as-cast aluminum grain structures, both direct magnetic flux and alternating electric current of 0 to 45 kHz were acted on the solidifing aluminum melts. The grain structures were significantly refined under the very low frequency range below 10 Hz in which it was expected that the fluid flow occured in the melt. A little grain refinement effect, however, was observed within the frequency range above 10 Hz in which the vibration was generated in the melt. Further, it was found that the grain refinement effect by the vibration was achieved by nonstationary wave, not by the action of stationary ones.
