Structural refinement of hypoeutectic Al-Si alloys by electromagnetic vibrations

Simultaneous imposition of alternating electric and stationary magnetic fields on a conducting liquid will induce a vibrating motion in the liquid which can lead into the formation and collapse of cavities in the liquid and affect the solidification structure. This phenomenon and the effects of the two main parameters of frequency and intensity of vibrations have been studied in an Al-7 wt pet Si alloy. An experimental apparatus which is based on a superconducting magnet and enables the simultaneous application of an alternating electric field with a frequency of up to 50 kHz and a magnetic field of up to 10 T has been designed and assembled. The thorough investigation, which has been carried out over wide ranges of intensity and frequency, clarified the effects of the two main parameters on the microstructural refinement brought about by electromagnetic vibration.