准三维C/C复合材料的层间剪切性能及其断裂机理

Interlaminar shear strength and fracture mechanism of quasi-3D C/C composites

以炭纤维针刺毡为预制体,采用化学气相浸渗(CVI)法或结合液相法制备了热解炭、树脂炭和沥青炭基质的准三维C/C复合材料,研究了这些材料的层间剪切性能及其断裂机理。结果表明:CVI基质炭比沥青基质炭更有利于C/C复合材料的层间剪切性能的提高;剪切强度随密度增高而增大,致密度越高,基体支撑越强,同时微裂纹和孔隙度就越低,断裂裂纹不易形成或扩展,强度性能就越好;纯沥青基质炭试样为"突发"的脆性断裂方式,其他基质炭试样表现为韧性断裂方式。

The semi-3D C/C composites were fabricated by needled felt through chemical vapor infiltration (CVI) and impregnation with liquid pitch and resin. Their interlaminar shear strengths and fracture mechanism were studied. The experimental results show that the interlaminar shear strengths of C/C composites with pyrolytic carbon is higher than that of C/C composites with pitch carbon; the interlaminar shear strengths of C/C composites increase with the densities increasing, the higher the density is, the stronger support the matrix can provide, and the less crack and pore they have, so the fracture-crack is difficult to extend and thus ensure the high strength; C/C composites with pure pitch carbon show sudden brittle fracture mechanism, and the others show tough mechanism.