Abstract：In order to study the change rule of directional solidification microstructure of aluminum alloy, the directional solidification process of AlSiCu aluminum alloy was simulated with the finite element simulation software ProCAST. The effects of different pouring temperature and pulling rate on the temperature gradient, solidliquid interface front, the width of the mushy zone, dendritic growth rate and secondary dendritic arm spacing during directional solidification of castings were simulated and analyzed. The results showed that the higher the pouring temperature, the greater the temperature gradient, and the smaller the concave at the front of the solidliquid interface, the narrower the width of the mushy zone. Which was more favorable for sequential solidification. With the increase of pulling rate, the dendritic growth rate first increased and then decreased. When the pulling rate was 200 μm/s and the maximum dendritic growth rate was 0.093 mm/s, the solidification structure of the casting was the best. When the pulling rate was greater than 300 μm/s or less than 200 μm/s, the dendritic growth rate would be slow, the dendritic growth would not be stable, and the secondary dendritic arm would be coarse. The better process parameters obtained by simulation were verified by testing, which could be used to prepare castings with better mechanical properties.
2019, Vol. 29 
