2007 Volume 48 Issue 3 Pages 538-543
The electromagnetic vibrations are applied to grain refinement of pure aluminum (99.7 mass%) and the effects of electromagnetic vibration frequency and temperature gradient on grain refinement are investigated. As the pure aluminum melt has been subjected to electromagnetic vibrations with a frequency range from 150 to 500 Hz, crystal grain has become small with increase of vibration frequency. To the contrary, the effect of refinement has become weak at the vibration frequency more than 1 kHz and this microstructure is similar to one of nonvibrated state. When the longitudinal temperature gradient in the specimen becomes gradual, refined area is remarkably extends. It is assumed that refinement by the electromagnetic vibrations is significantly affected by the temperature gradient.