Al_2O_3-SiC_w复合陶瓷的组织结构

Micro structure of the A12O3 - SiCwComposite Ceramics

用扫描和透射电镜研究了Al_2O_3-SiC_W复合陶瓷的成分、组织形貌及结构。结果表明,Al_2O_3和SiC_W两种结构相互穿插,结合致密。晶须取向随机分布,其结构为15R型,基体为六方晶型的α-Al_2O_3。电镜观察指出,在晶须内存有位错、孪晶和层错。该陶瓷的维氏硬度值为23.5GPa。根据压痕法测得的压痕裂纹长度和硬度值参数,计算其K_(IC)值为7.91MPa·m^(1/2)。裂纹进展形态表明,存在晶须拔出及裂纹偏转增韧机制。

The compositions, morphologies and microstructures of the AI2O3-SiCw composite ceramic were studied by SEM and TEM. The results show that the ceramic material has framework structure, in which A12O3 and SiCw insert each other and combine compactly. The orientation of whisker distributes stochastically and its structure is 15R type. The matrix is a-Al2O3 with hexagonal structure. Dislocations, twins and stacking faults were observed in the whiskers. The Vicker hardness of the ceramic material is 23.5GPa, The fracture toughness K1c is 7.91MPa calculated by the crack length of impression and hardness. The morphology of crack propagation indicate that there is the toughening mechanism of whisker's pull -out and crack deflection.