Co-authors​ :

 Guoqiang YU (CHINA), Chuyang XIE , Xiguang GAO , Yingdong SONG  

Ceramic Matrix Composites (CMCs) have become preferred materials for the high thrust-weight ratio aero-engine hot section components. CMCs structures are subjected to complex mechanical loads and coupled with corrosion factors such as high temperature and water oxygen during service environment, which can easily lead to damage and degradation of structural mechanical properties. Therefore, it is important to carry out the damage monitoring of CMCs structure and discover the damage and destruction of CMCs structure in time to avoid the sudden damage of structure. The non-destructive testing (NDT) techniques such as Acoustic Emission (AE) and Electrical Resistivity (ER) detection technologies transform microstructural damage that is difficult to be directly measured into quantifiable acoustic-electrical signals through instrument detection, recording and analysis. With the technologies, the damage status of CMCs can be monitored in real time, thus realizing the "intelligent" perception of CMCs.
In this paper, the acoustic-electrical response of three basic component materials (SiC matrix, SiC fiber bundle and SiC fiber bundle with BN interface), was characterized in the tensile damage process. Based on the acoustic-electrical response, the damage evolution information of each component material during the tensile process was analyzed. The theoretical models of SiC fiber deformation and fiber fracture were derived based on the law of resistance.
A novel mechanical-electrical coupling specimen for fiber filaments was designed, and a fiber filament force-electrical-acoustic coupling test system was built, which overcome the difficulty of fiber filaments dynamic resistance measurement. The tensile strength and resistivity of SiC fiber filaments after oxidation at different temperatures were statistically analyzed. A strong negative correlation between tensile strength and resistivity was found.