Development of Non-Dendritic Microstructure of Aluminum Alloy in Semi-Solid State under Ultrasonic Vibration

Abstract:

The effect of processing parameters on the semi-solid microstructure has been investigated in the course of semi-solid slurry preparation of A356 Al alloy by ultrasonic vibration method. The A356 melt in temperature of 630660°C was poured into a special metal cup, and exposed to ultrasonic vibration at 20 kHz or isothermal holding for a certain time after vibration. The results show that the semi-solid slurry with primary α-Al crystals smaller than 90 μm and an average shape coefficient F S (SF was defined as SF4 A/L2P) above 0.5 could be prepared by ultrasonic vibration for a time less than 144 s. In the isothermal holding period after a short time of ultrasonic vibration, the average particle diameter increased with the increase of holding time, but F S decreased at first, and then increased a little. It was discovered that ultrasonic vibration is a good method to prepare semi-solid slurry with fine and relatively round primary crystals due to cavitation and acoustic streaming effects.

• Periodical: Solid State Phenomena (Volumes 141-143)
• Pages: 451-456
• DOI: https://doi.org/10.4028/www.scientific.net/SSP.141-143.451
• Online since: July 2008
• Authors: Shu Sen Wu, Jun Wen Zhao, Li Ping Zhang, Ping An, You Wu Mao
• Keywords: Aluminium Alloy, Non-Dendritic Microstructure, Semi-Solid Slurry, Ultrasonic Vibration

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