Research On Filling Capacity Of Al-si Alloys In Rheological Die Casting Based On The Ultrasonic Vibration Slurry

Semi-solid rheoforming technology has advantages of short process flow and low production costs, and is catching many researchers'attention. Semi-solid alloys have good filling capacity is the precondition for rheoforming technology's extensive use. So, there is a need for researching semi-solid alloy's filling capability.In this paper, an experiment mold were designed for measuring Al-Si alloys'filling capacity in rheological rie casting process. Mold cavity is snake-shaped structure, and its size is 3×12×2250mm. The mold can reflect Al-Si alloys'filling capacity in the different parameters of rheological die casting process.In rheological die casting process, orthogonal experiment method and range method were used to research the influence of casting temperature, filling pressure and filling speed on the filling capacity of semi-solid ZL101 alloy and semi-solid AlSi20 alloy, which were prepared by ultrasonic vibration. The results shown that, in rheological die casting process, for ZL101 alloy, filing speed is the most effective parameter to filling capacity; for AlSi20 alloy, filing pressure is the most effective parameter to filling capacity. It is also found that alloy'filling capacity in liquid die-casting process is higher than in rheological die casting process; AlSi20 alloy'filling capacity is higher than ZL101 alloy'filling capacity both in liquid die-casting process and rheological die casting process.Filling samples'three different microstructure were studied to reveal the change rules of microstructure following filling length in the filling process. It is found that , for ZL101 alloy, grain size of primaryα(Al) phase andα(Al) were fined following filling length; for AlSi20 alloy, grain size of eutectic microstructure were fined following filling length, but grain size of primary Si phase had a little change. And in rheological die casting process, for different metallographic samples, though their location of microstructure is same, microstructure is following the rule that sample'filling length is longer, the grain size of microstructure is smaller.