Investigation On The Microstructure Of Rheo Turbulent Flow Shearing For AlSi9Mg Alloy

The greatest advantage of semi-solid rheological forming process is process flow short, low production costs and high production efficiency, which is in line with the requirements of Energy-saving and emission reduction and Green casting. In recent years it has become a major trend of semi-solid forming technology. In the semi-solid forming technology, the preparation of semi-solid alloy has been a hot research field at domestic and abroad.In this paper, water quenched samples of AlSi9Mg are prepared by using the self-designed Tilt rheological device with the Turbulence column. Pouring length, Angle of inclination, Shape of the pin fins, Forms of pin fins arrangement and Pin fins arrangement spacing are studied to find how they affect the microstructure of AlSi9Mg semi-solid alloy. Different vibration frequency and vibration dimension are studied to find the effect of the microstructure of semi-solid AlSi9Mg alloy. The results showed that:When pouring temperature is 615℃, Pouring length is 400mm,and angle of inclination is 45°, the obtained of semi-solid AlSi9Mg alloy melt is nearly ideal.Pin Fins parameters have great effect on the microstructure of semi-solid AlSi9Mg alloy. In this experiment, when the shape of Pin Fins is Droplets form, the form of Pin fins is arrange staggered, Row spacing S2 is 15mm, and column spacing L2 is 40mm, we can get good microstructure. Its solid fraction is 53.54%, grain size 5.59μm, and shape factor is 0.61.Vibration dimensions have great influence on the microstructure of semi-solid AlSi9Mg alloy, and we discover that two-dimensional vibration was better than one-dimensional vibration. In this experiment, when vibration is XZ direction with the vibration frequency of40Hz,we can get good microstructure. Its solid fraction is 37.56%, grain size is 5.53μm, and shape factor is 0.57.Vibration frequency has great influence on the microstructure of semi-solid AlSi9Mg alloy. When the three-dimensional vibration with the frequency of 30Hz, we can get good microstructure. Its solid fraction is 56.32%, grain size is 4.07μm, and shape factor is 0.51.