Y2O3与方石英对氧化硅陶瓷型芯性能的影响-材料加工工程专业论文.docxVIP

哈尔滨工业大学硕士学位论文 哈尔滨工业大学硕士学位论文 万方数据 万方数据 Abstract Silica-based ceramic cores are widely used in the field of aerospace at present. It has high flexural strength at room temperature and high efficient performance of leaching cores. Meantime, the price of the matrix materials is also the main advantage for silica-based ceramic cores. However, with the appearance of directional blades and single crystal blades, the silica-based ceramic cores’ properties have not met the casting requirements of new kind of blades. Considering the slight change of the particle size, composition and sintering temperature may lead to significant effects on the performance, the project study the three factors’ influences on ceramic cores’ properties. The program prepares the ceramic cores specimens which meet aviation criterion by the hot injection method and also test cores’ properties by conducting some relevant experiments, such as flexural strength, high temperature deflection at 1250℃and1550℃ etc. The results show that: With the particle size gradual decreasing, the high temperature deflections of ceramic cores present a decline trend, decreasing to 3.16mm. Furthermore, the decrease of particle size leads to the declining in the open porosity, descending from 0.296 to 0.260. At the meantime, this trend also causes the increase in shrinkages for silica-based ceramic cores. The addition of Y2O3 can enhance the flexural strength of the ceramic core and also maintain cores’ high temperature performance. At the meantime, it can improve the open porosity, which is helpful for leaching cores and strengthen technologies. Cristobalite can significantly reduce the ceramic cores’ thermal deformation at high temperature, with the addition increasing from 0% to 15%, the high temperature deflection at 1250℃ decreases 63.7% from 4.14mm to 1.50mm. moreover, the addition of cristobalite can decrease the shrinkages for ceramic cores, declining from 0.221% to 0.021%. When the sintering temperatur