【摘要】 以X-Y平面依次铺设炭纤维束、Z向穿插炭棒的4D软硬混编为预制体,采用沥青液相常压、高压浸渍/炭化-石墨化循环致密工艺制备4D-C/C复合材料。通过该材料Z向(炭棒方向)的拉伸实验,测定其拉伸性能和力学行为,并采用SEM分析试样表面及断口形貌。结果表明:宏观上拉伸试样以炭棒整体拔出的形式破坏;细观尺度上,试样表面形成了与载荷方向垂直的贯穿性裂纹,裂纹以2 mm左右的距离呈等间距分布;材料进一步的破坏过程中,基体裂纹在X-Y向纤维束中呈线性扩展,快速分割了基体材料,使4D-C/C复合材料的拉伸破坏演变为1D-C/C复合材料的破坏模式,由于炭棒与基体炭界面结合弱,炭棒以拔出方式失效和破坏。更多还原

【Abstract】 4D preforms woven with carbon fiber bundles and carbon rods were densified by repeated pitch impregnation,carbonization and high temperature treatment to obtain 4D-C/C composites.The tensile properties were investigated at room temperature when tension was applied in the carbon rod direction(Z direction).The strain and stress under tensile load were measured,and the surface morphologies of specimens after tensile failure were observed by scanning electron microscopy.Results indicate that the tensile strengths of the composite were controlled by interfacial shear strength between the carbon rod and the carbon matrix.The carbon rods were pulled out entirely from matrix after tensile failure,indicating that the material was not sufficiently reinforced by the carbon rods.Numerous micro-cracks were found on the surface of specimens after tensile failure.These were perpendicular to the load direction and equally spaced by a distance of about 2 mm.The damage model of 4D-C/C is similar to that of 1D-C/C.更多还原