Evolution of mechanical-acoustic-electrical properties on SiC filament underlaying an oxidation treatment

Abstract

Accurately obtaining the acoustic emission (AE) and electrical resistance (ER) responses of SiC filaments in the damage process is one of the keys to realizing the damage monitoring of SiC/SiC composite structures. A novel mechanical-electrical coupling specimen for fiber filament was designed based on the strength test strategy. During tensile failure, the difference in AE and ER responses between original and oxidation-treated SiC filaments was studied. The ER monitoring results show that the initial resistivity of SiC filaments is negatively correlated with their tensile strength. With increasing oxidation treatment temperature, the tensile strength of SiC filaments gradually decreases while the initial resistivity gradually increases. The AE monitoring results show that the AE signal of SiC fiber fracture has the characteristics of high amplitude, high energy, long duration, short rise time, and low peak frequency. A strong positive correlation is observed between the amplitude and energy of the AE signals of fiber fracture and the tensile strength of SiC filaments; the greater the tensile strength, the greater the amplitude, duration, and energy of the AE signals generated when the fiber fracture. In addition, the tensile modulus and resistance sensitivity coefficient of SiC filaments were measured.