二维机织碳纤维/碳化硅陶瓷基复合材料损伤分析

利用声发射技术全程监测二维机织C／SiC复合材料拉伸实验，通过声发射多参数分析法和断口显微观察，结合材料拉伸应力-变曲线，分析了二维机织C／SiC复合材料拉伸损伤演化过程和损伤机理。结果表明：材料拉伸损伤演化经历3个阶段：第一阶段为无损伤阶段，材料无损伤发生；第二阶段为损伤初始阶段．损伤主要为微裂纹开裂．并且微裂纹开裂基本上均匀发生在样品工作段；第三阶段为损伤加速阶段，损伤主要为宏观基体、界面开裂和纤维束断裂．井且集中发生在断口区域。损伤第二阶段与第三阶段的转换点在拉伸强度的76％左右，转换点的确定对二维机织C／SiC复合材料工程应用有重要意义。

DAMAGE ANALYSIS OF PLAIN WEAVE CARBON FIBER/SILICON CARBIDE CERAMIC MATRIX COMPOSITES

The acoustic emission(AE) technique was used to monitor the tensile progress of plain weave C/SiC composites.The damage evolution and AE characteristics were revealed through multi-parameter analysis,along with the mechanical response and fractography of the material.The results indicate that there are three distinct damage stages in the tensile progress.The first stage is designated as the undamaged stage,in which no damage takes place.In the second stage,the damage initiates as micro-cracking and takes place equably at the working region of specimen.The third stage is the rapid damage stage.In this stage,the macro matrix cracks propagation and fiber breakage are the main damage mechanism,and are concentrated at the fracture region of specimen.The turning point of the second stage to the third stage lies in 76 percent of the tensile strength,and this is important for engineering application of plain weave C/SiC composites.