Characterization of tensile behavior of a two-dimensional woven carbon/silicon carbide composite fabricated by chemical vapor infiltration

The tensile behavior of a two-dimensional woven carbon/silicon carbide composite has been characterized both by monotonic and loading/unloading tests. The composite shows markedly non-linear behavior with evident hysteresis loops, appreciable residual strains and continuously decreasing moduli. Both the loop width and residual strain have a continuous acceleration with applied stress, implying the composite failure precedes matrix cracking saturation. The shape of hysteresis loops is characterized by an initial parabolic region followed by a linear region. The preexisting matrix microcracks in as-processed specimens and multiple microcracks accompanied by extensive fiber pull-out in the failed specimens were observed, indicating large thermal residual stresses and relatively weak interfacial bonding exist in the present composite, respectively. Then the interfacial sliding stress and residual stress were quantitatively derived from the hysteresis analysis, and further used to predict matrix cracking stress and stress-strain behavior. Excellent agreement between predictions and experimental results was obtained.