Cracking Resistance of Silicon Carbide Composites by Single- and Double-Notched Specimen Techniques

摘要

This paper aims to evaluate fracture resistance of nanoinfiltration transient eutectic phase-sintered (NITE)-silicon carbide fiber-reinforced silicon carbide matrix (SiC/SiC) composites, using the single-edge notched bend (SENB) test and the double-notch tensile (DNT) test. Both SENB and DNT test results identified notch insensitivity of NITE-SiC/SiC composites. With the fact of notch insensitivity, unique proportional limit stress, and fracture strength were identified regardless of the presence of artificial notches. By applying the nonlinear fracture mechanics, micro- and macrocracking energies were separately estimated. Specifically, lower microcrack formation energy was identified compared with conventional low-stiffness composite system. Finally, superior crack resistance of NITE-SiC/SiC composites was clearly demonstrated.