高压浸渍-碳化制备沥青基碳/碳复合材料的组织与性能

Microstructure and Mechanical Properties of Pitch-based C/ C Composites Fabricated by H pic Technology

以 1K PAN基高强纤维为增强体 ,以调制中温煤沥青为基体前驱体 ,采用高压浸渍 -碳化工艺制备出了不同碳化压力状诚下的沥青基碳 /碳复合材料。通过对所得碳 /碳复合材料制件的弯曲性能试验及显微组织结构分析表明 ,材料的力学性能与碳化压力、密度、显微组织结构及界面结合状况有比较密切的联系。材料的断裂形式有韧性断裂、脆性断裂或它们的混合断裂形式 ,其密度和显微结构不同 ,表现出的断裂形式也不同。在制件的断面形貌上则表现为以纤维拔出为主或断面较为平整的脆断为主 (纤维和基体同时断裂 )

With 1K PAN-based HT carbon fibers as reinforcing materials and with modulated coal tar pitch as matrix precursor,bi-directional pitch-based carbon-carbon composites were obtained by HPIC ( High-Pressure Impregnation Carbonization) technology under different carbonization pressure.Through flexural property test and microstructure analysis of carbon-carbon composites.it was indicated that there were close relations between mechanical properties of composites and carbonization pressures,composite buld densities,microstructures and interface bonding strength.There were three kinds of composite fracture behaviors,namely tough fracture,brittle fracture and their hybrid fracture ( including both tough fracture and brittle fracture) .With different bulk densities and microstructures,the composites exhibited different fracture behaviors.From the morphology of fractured surface,we can see that carbon fibers'pulling out from matrix was the major form when tough fracturing.However,the fractured surface was smooth when brittle fracturing occur( carbon fibers and matrix fracture at same time) .