缝合密度对缝合C/C-SiC-ZrC复合材料的力学性能的影响

Effects of Stitch Density on Mechanical Properties of Stitched C/C-SiC-ZrC Composites

采用碳纤维无纬布缝合预制体,经"CVI+PIP"混合工艺制备了缝合C/C-SiC-ZrC复合材料。比较不同缝合密度对C/C-SiC-ZrC复合材料力学性能的影响,并通过扫描电子显微镜(SEM)观察复合材料断口的微观形貌。结果表明,在一定范围内,随着缝合密度的提升,缝合C/C-SiC-ZrC复合材料的拉伸强度有所下降,然而剪切强度有明显提升,最大可达24.94MPa。从SEM结果可以看出,无纬布缝合C/C-SiC-ZrC复合材料的拉伸破坏有明显假塑性断裂特性,在剪切载荷作用下,Z向纤维可有效抑制材料层间分层损伤。

The stitched C/C-SiC-ZrC composites were prepared by the ＂CVI＋PIP＂ mixing process using the carbon fiber non-staple fabric suture preform. The effects of different stitching densities on the mechanical properties of C/C-SiC-ZrC composites were compared, and the microstructure of composite fractures was observed by scanning electron microscopy （SEM）. The results show that within a certAln range, the tensile strength of the stitched C/C-SiC-ZrC composites slightly decreased and the shear strength has significantly increased （up to 24.94MPa） as the increase of the stitching density. It can be seen from the SEM results that the tensile fAllure of the non-weft-stitched C/C-SiC-ZrC composites has obvious pseudoplastic fracture characteristics. Under the action of shear load, the Z-direction fiber effectively inhibits interlayer delamination damage.