预制体纤维束缺失对于 SiC_f/SiC 复合材料 弯曲性能的影响

Effect of fiber-bundle-missing in fiber performs on flexural properties of SiC_f/SiC composites

摘要

通过主动引入缺陷，在 2.5D 编织 SiC 纤维预制体中精确构建 4 种不同严重程度的纤维束缺失缺陷（无缺失、缺失 1/3 束、缺失 2/3 束、缺失整束），并采用化学气相渗透结合聚合物浸渍裂解工艺制备成 SiC_f/SiC 复合材料。采用 XRD、SEM、CT 等表征方法与三点弯曲力学测试研究纤维束缺失缺陷对材料弯曲性能与失效机理的影响。结果表明，制备的 SiC_f/SiC 材料具有 BN 界面结合良好、基体致密的微观结构。纤维束缺失程度与材料弯曲性能呈显著负相关。无缺陷试样性能最优且最稳定，平均弯曲强度为 349.2 MPa，离散系数为 1.98%。随着纤维束缺失程度增加，强度逐步下降，整束缺失时强度降至最低值 246.6 MPa。失效模式由无缺陷条件下的统计性纤维控制失效，过渡为纤维局部缺失诱发的不确定性失效，最终转变为纤维整束缺失时由缺陷主导的确定性失效。微观分析表明，纤维束缺失不仅直接减少承载截面，更通过引发局部应力集中、改变裂纹扩展路径，降低了材料的承载能力。

Abstract

Fiber-bundle-missing defects of four severity levels (no missing bundle，1/3 bundle missing，2/3 bundle missing，and an entire bundle missing) are precisely introduced into 2.5D braided SiC fiber preforms by deliberate defect engineering，and the corresponding SiC_f/SiC composites are fabricated via a combined chemical vapor infiltration (CVI) and polymer infiltration and pyrolysis (PIP) process. The effects of fiber bundle missing defects on the flexural properties and failure mechanisms of the composites are investigated using XRD，SEM，and CT characterization together with three-point bending tests. The results show that the as-fabricated SiC_f/SiC composites possess a well-bonded BN interphase and a dense matrix microstructure. The severity of fiber bundle missing exhibits a significant negative correlation with the flexural performance of the material. The defect-free specimens exhibit the highest and most stable flexural properties，with an average flexural strength of 349.2 MPa and a coefficient of variation of 1.98%. As the severity of bundle missing increases，the flexural strength decreases progressively，reaching a minimum of 246.6 MPa for the specimens with an entire bundle missing. Specifically，the failure mode evolves from a stochastic，fiber-dominated failure in the defect-free condition，through an uncertainty-driven failure induced by local fiber absence，to a deterministic，defect-dominated failure when an entire bundle is missing. Microstructural analysis reveals that fiber bundle missing not only directly reduces the load-bearing cross-section，but also degrades the load-carrying capacity of the material by inducing local stress concentration and altering the crack propagation path.

关键词

SiC_f/SiC 复合材料 / 纤维束缺失 / 预制体缺陷 / 弯曲性能 / 微观结构

Key words

SiC_f/SiC composites / fiber-bundle-missing / preform defect / flexural property / microstructure

参考文献

[1] Yan W D，Feng Y J，Shen L L，et al. Multiscale investigation of PyC interphase—driven toughening mechanisms in SiC_f/SiC ceramic matrix composites[J].Composites Part A，2026，204：109624.

[2] Katoh Y，Snead L L，Henager C H，et al. Current status and recent research achievements in SiC/SiC composites[J].Journal of Nuclear Materials，2014，455（1/2/3）：387-397.

[3] Ding J H，Wen S F，Fu L，et al. Effect of carbon fiber preform structures on the mechanical properties of C_f@PyC/SiC composites[J].Journal of Alloys and Compounds，2023，930：167400.

[4] Yu H，Zhang J，Gao Y T，et al. 3D woven preforms and composites：current developments，material properties，and application potential[J].Polymer Composites，2026，47（5）：3897-3916.

[5] Zhang M Y，Gao X Z，Gao S X，et al. Braiding—process—induced damage and deformation of three—dimensional braided preform：a numerical investigation[J].Composite Structures，2025，367：119223.

[6] Li Q H，Gao Y T，Hu W F. Folding endurance and damage mechanisms of SiC fiber braided fabrics[J].Ceramics International，2023，49（23）：38339-38350.

[7] 许志远，谭志勇，徐培飞，等. 含缺陷 C/C—SiC 缎纹编织复合材料的压缩损伤及失效机制[J].材料工程，2024，52（9）：169-179.

[8] Xu Z Y，Tan Z Y，Xu P F，et al. Compression damage and failure mechanism of C/C—SiC satin woven composites with void defects[J].Journal of Materials Engineering，2024，52（9）：169-179.

[9] Katnic S P，Abdul Latheef M A，Sharp K，et al. Addressing processing limitations in SiC—based ceramic composites：a review of hybrid approaches and perspectives[J].Ceramics International，2025，51（30）：63501-63518.

[10] 过超强，赵毅，罗潇，等. 开孔 SiC_f/SiC 复合材料高温拉伸性能与失效破坏分析[J].失效分析与预防，2025，20（3）：199-207.

[11] Guo C Q，Zhao Y，Luo X，et al. High—temperature tensile properties and failure analysis of open—hole SiC_f/SiC composites[J].Failure Analysis and Prevention，2025，20（3）：199-207.

[12] Liu T L，Xiong L J，Chen Z F，et al. Pore defects repair of CCF/SiC composites fabricated by additive manufacturing[J].Ceramics International，2024，50（13）：24358-24367.

[13] Liang C Y，Gao X J，Fu L，et al. Pore evolution and mechanical response under locally varying density defects in ceramic matrix composites[J].Composites Part B，2024，279：111459.

[14] Mattoni M A，Yang J Y，Levi C G，et al. Effects of matrix porosity on the mechanical properties of a porous—matrix，all—oxide ceramic composite[J].Journal of the American Ceramic Society，2001，84（11）：2594-2602.

[15] Krishna R，Wilson P，Williams M A，et al. Effect of CVI—induced porosity on elastic properties and mechanical behaviour of 2.5D and 3D C_f/SiC composites with multi—layered interphase[J].Journal of the European Ceramic Society，2024，44（8）：4930-4948.

[16] Li S Y，Jiang Z H，Zhao G C，et al. X—ray tomography—assisted modeling of unidirectional mini SiC_f/SiC composites considering microstructure defects[J].Ceramics International，2025，51（6）：8178-8191.

[17] Talreja R. Multi—scale modeling in damage mechanics of composite materials[J].Journal of Materials Science，2006，41（20）：6800-6812.

[18] Lee K，Moorthy S，Ghosh S. Multiple scale computational model for damage in composite materials[J].Computer Methods in Applied Mechanics and Engineering，1999，172（1/2/3/4）：175-201.

[19] Wang B，Wang J L，Lyu Q H，et al. Multiscale damage and failure behavior of SiC_f/SiC composites with initial defects[J].Ceramics International，2025，51（14）：19366-19381.

[20] Li L B. Micromechanical modeling tensile and fatigue behavior of fiber—reinforced ceramic—matrix composites considering matrix fragmentation and closure[J].Journal of Composites Science，2021，5（7）：187.

[21] Han S L，Li Q Z，Cui Z，et al. Non—destructive testing and structural health monitoring technologies for carbon fiber reinforced polymers：a review[J].Nondestructive Testing and Evaluation，2024，39（4）：725-761.

[22] Ashebir D A，Hendlmeier A，Dunn M，et al. Detecting multi—scale defects in material extrusion additive manufacturing of fiber—reinforced thermoplastic composites：a review of challenges and advanced non—destructive testing techniques[J].Polymers，2024，16（21）：2986.

[23] Guo W N，Gao Y T，Sun L J. In—situ CT characterization of 2D woven SiC_f/SiC composite loading under compression[J].Science and Engineering of Composite Materials，2022，29（1）：394-402.

[24] Gowayed Y，Ojard G，Prevost E，et al. Defects in ceramic matrix composites and their impact on elastic properties[J].Composites Part B，2013，55：167-175.

[25] Shen L L，Zhu T Q，Shi S L，et al. Cross—scale static/dynamic shear damage evolution mechanism of 2D C/SiC ceramic matrix composite with transient hysteresis effect[J].Ceramics International，2024，50（10）：17898-17912.

[26] Qian W J，Zhang W N，Wu S C，et al. In situ X—ray imaging and numerical modeling of damage accumulation in C/SiC composites at temperatures up to 1200 ℃[J].Journal of Materials Science & Technology，2024，197：65-77.

[27] Li J，Wang X，Guo S，et al. Recent progress in the fabrication strategies and toughening mechanism of flexible ceramics and their applications[J].Journal of Materials Chemistry C，2024，12（44）：17742-17788.

[28] Bumgardner C H，Heim F M，Roache D C，et al. Analysis of SiC/SiC composites for energy applications at ambient conditions[J].Journal of the American Ceramic Society，2021，104（1）：481-491.

[29] Swolfs Y，McMeeking R M，Verpoest I，et al. Matrix cracks around fibre breaks and their effect on stress redistribution and failure development in unidirectional composites[J].Composites Science and Technology，2015，108：16-22.

[30] Jones R H，Henager C H. Subcritical crack growth processes in SiC/SiC ceramic matrix composites[J].Journal of the European Ceramic Society，2005，25（10）：1717-1722.

[31] Zhan C T，Liu Y Q，Chen J P，et al. Hoop tensile properties of SiC fiber—reinforced SiC matrix composite tubes with/without CVD—SiC coating[J].Journal of the European Ceramic Society，2024，44（14）：116707.