High Modulus and High Strength C/C-SiC Ceramic Matrix Composites by Fiber-Matrix Interface Tailoring via Modification of Fiber Surface and Matrix Precursor - Kerafam 2

通过纤维表面和基体前驱体改性实现纤维基体界面定制的高模量和高强度 C/C-SiC 陶瓷基复合材料 - Kerafam 2

• 批准号: 277680365
• 负责人: Professor Dr. Michael R. Buchmeiser
• 金额: --
• 依托单位: Lehrstuhl für Makromolekulare Stoffe und Faserchemie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2015
• 资助国家: 德国
• 起止时间: 2014-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/277680365?language=en
• 关键词: Modulus; Strength; SiC; Ceramic; Matrix

Based on the knowledge gained in the previous KeraFaM project, KeraFaM 2 aims to bring the mechanical properties of C/C-SiC materials closer to the theoretical limits expected from standard and high performance fibers.So far, the following insights were obtained:•Protection of the fibers against conversion during the siliconisation can be achieved by precise tailoring of the fiber-matrix-bonding (FMB). This prevents fiber-matrix-delamination (FMD) and favors segmentation cracks (SC) between fiber bundles, resulting in dense C/C-blocks separated by SiC matrix. Mechanical properties of the resulting C/C-SiC composites are below the theoretical limits. The low utilization rate of fiber properties is attributed to the C/C block structure favoring a fiber bundle pullout.•The formation of the crack structure of the samples observed after carbonization does already start during curing of the resin.•The choice of matrix resin influences the microstructure. The essential difference between the resins are the phenolic and solvent content.•The Ultra High Modulus (UHM) fibers used during the project could not be processed after desizing due to their brittleness.•The micro crack formation for different FMBs during pyrolysis can be modeled employing the Finite Element Method (FEM).The collaboration between the team ceramic composites and structures at the DLR in Stuttgart, the DITF in Denkendorf and the chair of experimental physics 2 at the University of Augsburg has proven to be complementery and effective during KeraFaM. Based on this successful collaboration, the following goals will be pursued in KeraFaM 2:•To raise the fiber utilization rate substructuring of the C/C blocks is intended. This could be achieved by a multilayer sizing. This sizing is used to obtain a more defined tailoring of the FMB and to protect the fibers from conversion. In a second approach a microporous C-matrix will be produced. Both concepts are expected to favor single fiber pullout over fiber bundle pullout.•Analysis of cross-linking reactions, in situ acoustic emissions analysis and nano-CT examination starting at the curing stage of the resin addresses understanding of the microstructure formation. This will ultimately lead to better control of the microstructure and the resulting C/C-SiC composite properties.•The FE-Model will be refined by taking into account experimentally obtained material parameters in order to realistically represent microstructure development for different FMB values. The resulting model will be validated by acoustic emissions analysis and SEM measurements.•The impact of phenolic content of the matrix resins on residual carbon mass, shrinkage and microstructure after carbonization will be evaluated varying the proportion of aromatic compounds of the matrix resin.•To allow further processing and to protect fibers from conversion to SiC, UHM fibers will be modified by applying an additional sizing on top of the as-received sizing.

基于之前 KeraFaM 项目中获得的知识，KeraFaM 2 旨在使 C/C-SiC 材料的机械性能更接近标准和高性能纤维预期的理论极限。到目前为止，获得了以下见解：•保护通过精确定制纤维基体粘合 (FMB)，可以防止硅化过程中纤维发生转变，从而防止纤维基体分层 (FMD) 并有利于分段裂纹 (SC)。 C/C-SiC 复合材料的机械性能低于理论极限，这归因于 C/C 块结构。有利于纤维束拔出。•碳化后观察到的样品裂纹结构的形成在树脂固化过程中已经开始。•基体树脂的选择影响微观结构。树脂之间的本质区别在于酚醛和溶剂含量。•这该项目中使用的超高模量（UHM）纤维由于其脆性而无法在退浆后进行加工。•不同FMB在热解过程中微裂纹的形成可以采用有限元法（FEM）进行建模。陶瓷团队之间的合作斯图加特德国航天中心 (DLR)、登肯多夫 (Denkendorf) 的 DITF 和奥格斯堡大学实验物理 2 系主任的复合材料和结构研究已被证明是互补且有效的KeraFaM。基于这次成功的合作，KeraFaM 2 将实现以下目标：•提高C/C 块的光纤利用率。这可以通过多层上浆来实现。第二种方法是对 FMB 进行更明确的定制，以防止纤维发生转换，这两种概念预计都将有利于单纤维拉拔。•分析。从树脂固化阶段开始进行交联反应、原位声发射分析和纳米 CT 检查，以了解微观结构的形成，这最终将有助于更好地控制微观结构和所得的 C/C-SiC 复合材料。性能。•将通过考虑实验获得的材料参数来完善有限元模型，以便真实地表示不同 FMB 值的微观结构发展。所得模型将通过声发射分析和 SEM 测量进行验证。•酚类含量的影响。矩阵的将通过改变基体树脂中芳香族化合物的比例来评估树脂的残余碳质量、碳化后的收缩率和微观结构。为了允许进一步加工并防止纤维转化为 SiC，将通过在顶部施加额外的上浆剂来对 UHM 纤维进行改性收到时的尺寸。