Fabrication Processing and Evaluation on Thermal Shock Damage of C/SiC Composite

Carbon fiber reinforced SiC matrix composites (C/SiC) is one of attractive candidates in the ultrahigh temperature components such as turbine rotor and internal combustion part. The objective of this paper is to investigate the characterization of C/SiC composite containing nano scale SiC powder. Especially, the effects of thermal characteristics and thermal shock damage on the C/SiC composite using nondestructive technique were evaluated in detail because the composite is expected to be used in the conditions of high temperature. The C/SiC composite was fabricated by a liquid phase sintering (LPS) process with commercial SiC powder of about 30 nm. The matrix region for C/SiC composites prior to the sintering were prepared by a slurry infiltration technique. The composite material was consolidated at the temperature of 1820°C, pressure of 20 MPa and 2 hours holding time in hot press, respectively. The fractured surfaces of C/SiC composites were also observed to examine the fracture profile of fiber bundle region and the adhesion between carbon fabric and matrix. The parameters such as velocity and attenuation ratio of ultrasonic wave were used to evaluate nondestructively the degree of damage of the composite underwent cyclic thermal shock.