Strength of metal impregnated C/C under tensile cyclic loading

An experimental investigation is conducted on the tensile cyclic behavior of metal impregnated composites based on a preformed yarn method such as Cu-C/C and Si-C/C together with C/C. Specimens are loaded cyclically in tension and tension. Their S-N curves and the fatigue strength of about 0.8UTS at around N = 10(4) were obtained. Macroscopic and microscopic characteristics are discussed to yield the cyclic failure mechanism as follows. In a low cycle region, the decrease of shear resistance caused by wear at the fiber/matrix interface increases the probability of fiber break, while after about 10(4) cycles the smoother interface and longer debonding area suppress the decrease of shear resistance. Thus, the probability of fiber break does not increase. (c) 2006 Elsevier Ltd. All rights reserved.