机械搅拌对Al-Si合金凝固组织的影响及其模拟试验

Effect of Mechanical Stirring on Solidification Structure of Al-Si Alloys and Its Experimental Simulation

采用机械搅拌的工艺,以NH4Cl水溶液和Al-Si合金为研究对象,设计了两组机械搅拌实验,探讨了不同参数条件下搅拌对等轴晶形成的影响。试验结果表明:搅拌器最适宜的位置是液面处,搅拌使液面附近的游离晶增多。随着NH4Cl水溶液浓度或Al-Si合金中Si含量的增加以及搅拌转速的增加,晶粒细化程度提高,获得分散均匀、细小的等轴晶。同时,搅拌也易卷入气体,使铸件产生气孔、缩松。

By the mechanical stirring technology in this paper, regarded ammonium-chloride solution and Al-Si alloys as the research object, two series of experiments by mechanical stirring had designed, all these attempted to study the effect of formation of equiaxed grains by changing different parameters of mechanical stirring. The experimental results showed that free crystals near solution surface increased under stirring, the most optimal position for stirring was the solution surface. And the extent of refinement was improved as the concentration of ammonium-chloride solution or the silicon content in Al-Si alloy ingots is increasing, and homogeneous and finer equiaxed grains obtained. However, porosity and shrink were formed during stirring because of gas involved.