TEMPERATURE-DEPENDENT PROPORTIONAL LIMIT STRESS OF CARBON FIBER-REINFORCED SILICON CARBIDE CERAMIC-MATRIX COMPOSITES

In this paper, the temperature-dependent proportional limit stress of carbon fiber-rein forced silicon carbide ceramic-matrix composites (C/SiC CMCs) is investigated using the energy balance approach. The temperature-dependent micromechanical parameters of fiber and matrix modulus, fiber/matrix interface shear stress and interface debonded energy, and matrix fracture energy are incorporated into the analysis of the micro stress analysis, fiber/matrix interface debonding criterion and energy balance approach. The relationships between the proportional limit stress, fiber/matrix interface debonding and temperature are established. The effects of fiber volume fraction, fiber/matrix interface shear stress, interface frictional coefficient, interface debonded energy and matrix fracture energy on the proportional limit stress and fiber/matrix interface debonding length versus temperature curves are discussed. The experimental proportional limit stress and fiber/matrix interface debonding length of 2D C/SiC composite at elevated temperatures of 973 K and 1273 K are predicted. For C/SiC composite, the proportional limit stress of C/SiC composite increases with temperature, due to the increasing offiber/matrix interface shear stress and decreasing of the thermal residual stress.