三维针刺C/SiC复合材料的结构特征和力学性能

采用化学气相渗透法制备了在厚度方向上具有纤维增强的三维针刺碳纤维增强碳化硅(C/SiC)陶瓷基复合材料,复合材料的密度和气孔率分别为2.15 h/cm3和16%.三维针刺C/SiC复合材料中的针刺纤维将各层紧密结合在一起,其层间抗剪切强度显著提高,为95MPa,比二维碳布叠层C/SiC复合材料的剪切强度(35MPa)高171.4%.三维针刺C/SiC复合材料的拉伸强度和弯曲强度分别为159MPa和350MPa,断裂模式为非脆性断裂,包括:裂纹扩展、偏转,碳纤维的拉伸断裂和逐步拔出.

MICROSTRUCTURE AND MECHANICAL PROPERTIES OF THREE-DIMENSIONAL NEEDLED C/SiC COMPOSITE

A three-dimensional needled carbon fiber reinforced silicon carbide (3D needled C/SiC) ceramic matrix composite in the through-the-thickness direction was fabricated by the chemical vapor infiltration process. The resulting composite has a bulk density of 2.15 g/cm3 and an open porosity of 16%. The adjacent layers for thickness direction in the 3D needled C/SiC composite are interlinked perfectly together by needling fibers and this greatly improves the interlaminar shear strength of the composite. The interlaminar shear strength of the 3D needled C/SiC composite is 95 MPa (improved 171.4% compared with 2D C/SiC composite, 35 MPa),and the tensile strength and flexural strength of the 3D needled C/SiC composite are 159 MPa and 350 MPa, respectively. The composite exhibits a non-brittle failure behavior including propagation and deflection of cracks, fracture and pullout of fibers.