SiCp/A357复合材料流动性数值模拟与实验研究

搅拌铸造方法易于成型大尺寸复杂的复合材料零件,但是碳化硅颗粒加入使得复合材料的流动行为变得更加复杂,开展复合材料流动性研究至关重要。本文建立了SiCp/A357复合材料的流动模型,采用数值模拟及实验研究相结合的方法,研究了浇注温度及碳化硅体积分数对SiCp/A357复合材料流动性及流动充型过程碳化硅分布的影响。结果表明,随着浇注温度的提高SiCp/A357复合材料的流动性升高,这一趋势在半固态区间更为明显；但是随着浇注温度的提高,试样前端的碳化硅体积分数较末端减少加剧,复合材料中碳化硅的整体分布均匀性降低；随着碳化硅体积分数的增加SiCp/A357复合材料的流动性降低,且随着碳化硅体积分数的增加,试样前端碳化硅的体积分数减少程度减弱,整体的均匀性提高。上述的模拟结果与实验结果具有较好的一致性。

Simulated and Experimental Study on Fluidity of SiC/A357 Composites

Stir casting process are well suited for large scale and complex composite components,but the flow behavior becomes complex due to the addition of SiC particles, therefore the mould filling process becomes the key factors of preparing high quality composite castings. In this study, the flow model of SiCp/A357 composites was built through numerical method, and the fluidity and SiC particle distribution were tested with fluidity test. The results showed that numerical simulation was roughly accord with fluidity test. The fluidity of SiCp/A357 composites increased with pouring temperature, which was more obvious in semi-solid state. The volume fraction of SiC particles at the flow-front was lower than the end, the whole homogeneity of SiC particles decreased, this tendency intensified with pouring temperature increasing. The fluidity of SiCp/A357 composites decreased with volume fraction. With volume fraction increasing, the tendency of SiCp reduce at flow front slowed, the homogeneity of SiCp inproved.