PREPARATION OF SEMISOLID 5052 ALUMINUM ALLOY SLURRY BY INDIRECT ULTRASONIC VIBRATION

Abstract

A new indirect ultrasonic vibration (IUV) apparatus was employed to prepare semisolid 5052 aluminum slurry. The effects of IUV temperature and time on the morphology of the semisolid slurry were studied. The results indicate that semisolid slurry with fine and globular primary grains can be obtained by applying IUV from the liquidus temperature (643 ) of this alloy or a higher temperature for about 50 s. When IUV is applied through the bottom of the metal cup at 643 ,a lot of nuclei form near the bottom of metal cup and these nuclei grow into globular grains. In this stage, the average diameter of primary grains decreases as IUV time increased up to 30 s and then it increases with further increasing of IUV time from 30 s to 60 s, and the average shape coefficient of primary grains increases as IUV time increased. When the IUV is applied at 640 , dendrites can be broke up and a mixture structure consisted of rosette and globular grains with a average diameter of 105 μm is obtained.