复合纤维含量对精铸硅溶胶型壳强度及透气性的影响

摘要

采用陶瓷和尼龙复合纤维增强熔模精铸硅溶胶型壳，通过测试与分析复合纤维增强硅溶胶型壳的常温及焙烧后强度和透气性，研究复合纤维含量对硅溶胶型壳强度和透气性的影响规律，确定复合纤维含量与焙烧温度和型壳强度的关系，并通过 SEM 对型壳试样断口形貌进行观察和分析。结果表明：复合纤维对硅溶胶型壳强度和透气性的影响显著，当复合纤维含量小于0.6%(质量分数)时，硅溶胶型壳强度和透气性同时增大；当复合纤维含量大于0.6%时，型壳常温及焙烧后强度开始减小，焙烧后基体中孔隙率增加，型壳透气性继续增大；当复合纤维含量为0.6%、焙烧温度为1050℃时，型壳焙烧后强度达到最大值。%Ceramic and nylon composite fibers were used to enhance silica sol shell of investment casting. The effects of composite fiber content on the strength and breathability of silica sol shell were studied by testing and analyzing the green and fired strength and breathability. Meanwhile, the relationships among composite fiber content and firing temperature and fired strength of shell were established. The fracture appearances of shell specimens were observed by scanning electron microscopy (SEM). The results indicate that the effect of composite fibers on strength and breathability of silica sol shell is obvious. When composite fiber content is less than 0.6% (mass fraction), the strength and permeability of silica sol shell both increase. When composite fiber content is more than 0.6%, the green strength and fired strength of fiber-reinforced shell decrease firstly, and the matrix porosity increases, the shell breathability continues to increase; When the composite fiber content is 0.6% and firing temperature is 1050℃, the fired strength reaches maximum value.