An approach for describing crack growth in non-oxide ceramic matrix composites

A dynamic crack-growth model using discrete, two-dimensional fiber bridges has been developed to predict slow crack growth in ceramic composites containing nonlinear, creeping fibers in an elastic matrix and for the case where fiber/matrix interphase removal occurs by volatile oxidation. Mechanics for frictional bridging, nonlinear fiber-creep equations, and appropriate fiber compliance expressions are used to compute crack extension dynamically. Predictions for crack lengths, crack-velocity, and kinetic data for Nicalon-CG and Hi-Nicalon composites in bending at 1173K to 1473K in inert and oxidative environments are in good agreement with experimental data.