陶瓷纤维长度对复合精铸型壳抗弯强度与透气性的影响及增强行为

为了分析纤维长度对陶瓷纤维增强硅溶胶型壳抗弯强度与透气性的影响及增强行为,采用1~6mm六种不同长度陶瓷纤维制备硅溶胶型壳试样。研究结果表明,陶瓷纤维长度对硅溶胶型壳强度和透气性的影响显著,随着陶瓷纤维长度的增加,型壳的抗弯强度先增大后减少,型壳的透气率先增大后减小再增大。当陶瓷纤维长度为4mm时,型壳的常温及焙烧后抗弯强度达到最大值,分别为2.97 MPa和6.84 MPa;型壳的透气率达到最大值2.90。当陶瓷纤维长度大于4mm时,纤维在型壳中分散性变差,纤维的桥联作用得不到有效发挥,型壳孔隙率减少,导致型壳强度和透气性变小。

Effects and enhanced behavior of ceramic fiber length on bending strength and breathability of composite shell for investment casting

In order to analyze the influence of fiber length on the bending strength and breathability of the ceramic fiber reinforced silica sol shell,the ceramic fibers with six different lengths from 1 mm to 6 mm were added to the silica sol slurry to reinforce shell.The results show that the length of the ceramic fiber has a significant effect on the strength and breathability of silica sol shell.With the increase of the ceramic fiber length,the bending strength of the shell increases first and then decreases,and the breathability of the shell increases first,then decreases and increases again.When the fiber length is 4 mm,the green strength and fired strength of the shell reach the maximum about 2.97 MPa and 6.84 MPa,respectively,and the breathability of the shell also reaches the maximum about 2.90.When the fiber length is more than 4 mm,the dispersion of fiber in shell gets worse,and the influence of fiber bridging is not obviously effective.The porosity of the shell reduces,which leads to the decrease of the strength and breathability of the shell.