SiC晶须增韧Al_2O_3陶瓷组成优化及其断裂行为的研究

Compositional Optimization and Fracture Characters of SiC Whisker Toughened Al_2O_3 Ceramic Materials

对ＳｉＣ晶须增韧Ａｌ_２Ｏ_３陶瓷刀具材料的晶须配比进行了理论分析，提出了最佳晶须配比的原则，导出了晶须含量与界面最大剪应力对基体最大正应力比值的关系。采用ＳＥＭ和有限元法分析了该材料的断裂模式。结果表明晶须含量为２０～３０Ｖｏｌ％时增韧效果最佳，在此配比范围内的ＳｉＣ晶须增韧Ａｌ２Ｏ３陶瓷材料的断裂过程为：晶须和基体界面拉伸开裂→晶须基体界面剪切分离→晶须或基体断裂。

The whisker content of SiCw toughened Al_2O_3 ceramic cutting tool material has been analyzed theoretically; the principle of obtaining optimized whisker content is presented. The relationship of the maximum shear stress in boundary and maximum tensile stress in matrix with whisker content has been investigated. The fracture charaeters of this material are studied by finite element methods. Results indicated that when containing 20-30 vol% SiCw, this ceramic material exhibited the best toughening results. Its fracture processes are: debonding of interface owing to the tensile stress in radial direction, debinding of interface owing to the shear stress, fracture of the whisker or matrix .