Mechanical Behavior of Carbon/Phenolic Ablative Composites for Nozzle Application

Carbon/phenolic composites were fabricated by an infiltration of phenolic resin into eight harness satin woven fabric of PAN-based carbon fibers. The tensile and compressive behaviors of carbon /phenolic composites were observed in with-laminar/0-deg warp, with-laminar/45-deg warp, with-laminar/90-deg warp, and across-laminar directions. The tensile and compressive tests were performed at 200-700 C under N2 atmosphere to reduce the oxidation of phenolic resin. The tensile strengths of carbon/phenolic composites in with-laminar/0-deg warp and with-laminar/90-deg warp directions were about 7-10 times higher than those in with-laminar /45-deg warp direction, which was analyzed due to a change of fracture mode from fiber pull-out to tensile failure of fibers. The compressive strengths of carbon/phenolic in across-laminar direction were about 10 times higher than those in with-laminar /45-deg warp direction. The compressive failure occurred by tensile fracture of fibers in across-laminar direction, and was changed into delamination fracture by buckling of fibers in the with-laminar/45-deg warp direction. (Author)