Stability of alumina- and mullite-based fibers by thermal exposure: experimental study and phase-field modeling

氧化铝和莫来石基纤维的热暴露稳定性：实验研究和相场建模

基本信息

批准号：
327298888
负责人：
Dr. Julia Kundin
金额：
--
依托单位：
Fachgebiet Keramische Werkstoffe und Bauteile
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2017
资助国家：
德国
起止时间：
2016-12-31 至 2020-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/327298888?language=en
关键词：
Stability alumina mullite based fibers

项目摘要

The efforts to achieve high strength and damage tolerant oxide-based ceramic matrix composites (Ox-CMCs) were, for a long time, focused on searching for new matrix systems and proceeding routes, as well as on the adjustment of the fiber-matrix-interface. Nowadays, such "conventional" methods seem to have reached the limits of their capacity.In the last decade, several studies on oxide fibers and composites revealed another way to enhance the performance of Ox-CMCs by optimal utilization of the oxide fibers. Being used as reinforcements, these fibers are responsible for the mechanical performance of the composites. As it is well-known, oxide fibers present an excellent strength and stiffness in as received conditions. However, commercially available polycrystalline fibers show strength loss when they are exposed to elevated temperatures due to grain growth. Thus, attention has been given to this subject, since such temperatures can be easily reached during processing and application of Ox-CMCs.The goal of the present proposal is to understand the mechanisms and to successively predict microstructural changes of alumina- and mullite-based fibers embedded in ceramic matrices depending on the matrix composition, the processing conditions, and additional heat treatments performed. This will be achieved by combining experiments and phase-field modeling as necessary to bridge the different effects that are involved. Furthermore, the effect of the microstructural changes on the quasi-static and long-term performance of the fibers at high temperatures should be evaluated.For that, minicomposites comprised of one fiber bundle are to be manufactured under different conditions. The grain size distribution and morphology of the fibers in dependency on the matrix composition will be experimentally investigated after exposure to elevated temperatures and mechanical load. The corresponding changes of the strength and the creep performance will be investigated by means of mechanical characterization techniques and correlated to the microstructure evolution. In parallel, the effective growth mechanisms will be studied through phase-field modeling combined with the feedback from the experimental results. The model will take into account the anisotropy of crystal growth, the grain boundary diffusion, the formation and evolution of impurities and pores. Special attention will be given to the abnormal grain size distribution and possible diffusion mechanisms between fiber and matrix.As a main result, it is expected that the enhanced predictability of the fiber properties (in composites) will show a way to determine the matrix composition used. By doing so, it will be possible to reduce the strength loss of the ceramic fibers during composites lifetime. Consequently, an adjusted matrix composition will provide flexibility in the tailoring of composite properties to the target application in terms of strength and durability.

长期以来，为实现高强度和耐受耐氧化物陶瓷基质复合材料（OX-CMC）所做的努力一直致力于寻找新的矩阵系统和程序途径，以及调整光纤 - 矩阵 - 界面。如今，这种“常规”方法似乎已经达到了其能力的限制。在过去的十年中，几项关于氧化物纤维和复合材料的研究揭示了另一种方法，可以通过最佳利用氧化物纤维来增强OX-CMC的性能。这些纤维被用作增援部队，负责复合材料的机械性能。众所周知，氧化物纤维在接收条件下具有出色的强度和刚度。但是，由于晶粒生长，市售的多晶纤维暴露于温度升高时，它们显示出强度损失。因此，由于可以在OX-CMC的处理和应用过程中很容易达到此类温度，因此已经对该主题进行了关注。本提案的目的是了解机制，并依次预测基于氧化铝和mullite的微观结构变化。根据基质组成，加工条件和进行其他热处理的纤维嵌入陶瓷基质中。这将通过将实验和相位模型结合起来，以弥合所涉及的不同效果的必要条件来实现。此外，应评估微观结构变化对纤维在高温下的准静态性能和长期性能的影响。对于在不同条件下由一个纤维束组成的微型复合材料。暴露于温度升高和机械负荷后，将对纤维的晶粒尺寸分布和依赖于基质组成的形态进行实验研究。强度和蠕变性能的相应变化将通过机械表征技术进行研究，并与微结构演化相关。同时，将通过相位模型结合实验结果的反馈来研究有效的生长机制。该模型将考虑晶体生长的各向异性，晶界扩散，杂质和毛孔的形成和演变。将特别注意纤维和基质之间的异常晶粒尺寸分布和可能的扩散机制。作为主要结果，预计纤维性能的增强性（在复合材料中）将显示出一种确定使用的基质组合物的方法。通过这样做，可以在复合材料寿命期间降低陶瓷纤维的强度损失。因此，根据强度和耐用性，调整后的矩阵组合物将在对目标应用程序的复合特性量身定制方面具有灵活性。

项目成果

期刊论文数量（7）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Phase-field modeling of grain growth in presence of grain boundary diffusion and segregation in ceramic matrix mini-composites

DOI：
10.1016/j.commatsci.2021.110295
发表时间：
2021-04
期刊：
Computational Materials Science
影响因子：
3.3
作者：
J. Kundin;Hedieh Farhandi;Kamatchi Priya Ganesan;Renato S. M. Almeida;K. Tushtev;K. Rezwan
通讯作者：
J. Kundin;Hedieh Farhandi;Kamatchi Priya Ganesan;Renato S. M. Almeida;K. Tushtev;K. Rezwan

Joining oxide ceramic matrix composites by ionotropic gelation

DOI：
10.1111/ijac.13507
发表时间：
2020-04
期刊：
International Journal of Applied Ceramic Technology
影响因子：
2.1
作者：
Renato S. M. Almeida;Hedieh Farhandi;K. Tushtev;K. Rezwan
通讯作者：
Renato S. M. Almeida;Hedieh Farhandi;K. Tushtev;K. Rezwan

Obtaining complex-shaped oxide ceramic composites via ionotropic gelation

通过离子凝胶化获得复杂形状的氧化物陶瓷复合材料

DOI：
10.1111/jace.15990
发表时间：
2019
期刊：
Journal of the American Ceramic Society
影响因子：
3.9
作者：
Almeida RSM;Pereira TFS;Tushtev K;Rezwan K
通讯作者：
Rezwan K

Phase-field simulation of abnormal anisotropic grain growth in polycrystalline ceramic fibers

DOI：
10.1016/j.commatsci.2020.109926
发表时间：
2020-12
期刊：
Computational Materials Science
影响因子：
3.3
作者：
J. Kundin;Renato S. M. Almeida;Hesham Salama;Hedieh Farhandi;K. Tushtev;K. Rezwan
通讯作者：
J. Kundin;Renato S. M. Almeida;Hesham Salama;Hedieh Farhandi;K. Tushtev;K. Rezwan

Numerical investigation of the recrystallization kinetics by means of the KWC phase-field model with special order parameters