Effect of the Intensity and Frequency of Electromagnetic Vibrations on Refinement of Primary Silicon in Al-17%Si Alloy

Abstract

Electromagnetic vibrations, which are the interaction between a static magnetic field and an alternating electric field, were applied to the structural refinement of Al-17%Si hyper-eutectic alloy. The relationship between the intensity and frequency of the electromagnetic vibrations and the refinement of primary silicon particles is quantitatively investigated. In the frequency range from 10 Hz to 30 kHz, the vibration frequency near 1 kHz was most effective for the refinement of silicon particles, and silicon particles of sizes up to approximately 5 mm were refined at that frequency. The level of refinement increased with increasing the intensity of electromagnetic vibrations. A primary silicon particle was sufficiently refined with a magnetic field intensity of only approximately 1.6 Tesla (T).

Effect of Electromagnetic Vibration Frequency and Temperature Gradient on Grain Refinement of Pure Aluminum

“…It was supposed that grain refinement by the electromagnetic vibrations is hardly effective at the frequencies over 1 kHz. This effect of vibration frequency on the grain size is similar in tendency to the previous results on several alloy systems [24][25][26][27][28][29][30] and pure metals, 31,32) although the optimum frequency for refinement is different.…”

“…The effective frequency range for structural refinement of metallic materials was almost below the frequency of 1 kHz. [24][25][26][27][28][29][30][31][32] On the other hand, it was also reported that apparent glass-forming ability was enhanced by imposition of the electromagnetic vibrations with frequency of 5 kHz.…”

“…In the casting process accompanied solidification phenomenon, rapid cooling, [3][4][5][6] addition of refiners, [7][8][9][10][11][12] application of vibrations, [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32] etc. are considered as a structural refinement method.…”

“…In contrast, the application of vibrations is able to refine microstructure even in bulk materials without a refiner. Mechanical vibration, such as mechanical mold vibration 13,14) or ultrasonic vibration, [15][16][17][18][19] and electromagnetic vibrations [20][21][22][23][24][25][26][27][28][29][30][31][32] are considered as an imposition method of vibrations. The application of mechanical vibrations such as ultrasonic ones enables not only refinement of the crystal grain, but also uniform dispersion of inclusion materials, degassing, improvement of metal feeding, etc.…”

Effect of Vibration Timing on the Microstructure and Microtexture Formation of AZ91D Magnesium Alloys during Electromagnetic Vibration

“…They [3][4][5][6][7][8][9][10][11] found that the microstructures could be substantially refined when vibration frequency fell into a suitable interval, more often than not, within the range from about 500 Hz to less than 2000 Hz.…”