强界面结合层状超高温陶瓷基复合材料温度相关性强韧性能及其表征方法研究

Compared to the monolithic ultra-high temperature ceramic matrix composites, the laminated ultra-high temperature ceramic matrix composites with strong interfaces have better obdurabilities and oxidation resistance, which would have broad application and development spaces in the high temperature fields. Considering the harsh demanding of the obdurabilities of laminated ultra-high temperature ceramic matrix composites with strong interfaces owing to the large temperature fluctuations during their causative processes and the current research status cannot meet the significant requirements for the acquirements of high temperature obdurabilities, this project will make researches on the laminated ultra-high temperature ceramic matrix composites with strong interfaces from the macro-microscopic view using the combination methods of theory, experimental analysis and numerical simulation. The systematic researches on the obdurabilities of laminated ultra-high temperature ceramic matrix composites with strong interfaces and their influencing mechanisms at different temperatures will be conducted, and a theoretical characterization model for the obdurabilities having the profound physical background and including the effects of causative temperatures will be developed. And then the main influencing parameters of the obdurabilities and their evolution laws with increase of temperature will be evaluated reasonably. The innovation in the basic theories of the high temperature obdurability and principle for strengthening and toughening design will be made. The research achievements of this project can provide the effective characterization methods for the temperature dependent obdurabilities of laminated ultra-high temperature ceramic matrix composites with strong interfaces, and can provide the theoretical basis and technical reserve for strengthening and toughening design of the composites under different causative temperatures.

相比于块体超高温陶瓷基复合材料，强界面结合层状超高温陶瓷基复合材料具备更好的强韧性能和抗氧化性能，在高温领域将有着广阔的应用和发展空间。鉴于强界面结合层状超高温陶瓷基复合材料在使役历程中所要经历的大幅度的温度变化对其强韧性能提出的苛刻要求以及目前研究现状难以满足对其高温强韧性能获取的重大需求，本项目采用理论、试验与数值模拟相结合的手段，从宏细观相结合的角度，对强界面结合层状超高温陶瓷基复合材料在不同温度下的强韧性能及其影响机制进行系统研究，建立具有深刻物理背景的可计及使役温度影响的强韧性能理论表征模型，合理评价控制材料强韧性能的主要机制及其随温度的演化规律，在强界面结合层状超高温陶瓷基复合材料高温强韧性能和强韧化设计原理等基础理论方面有所创新。本项目研究成果可为强界面结合层状超高温陶瓷基复合材料温度相关性强韧性能提供有效的表征方法，为材料在不同使役温度下的强韧化设计提供理论基础与技术贮备。

鉴于应用于高温领域的陶瓷材料在不同温度下使用时都必须达到的高精度设计要求以提高其应用可靠性，研究强界面结合层状超高温陶瓷基复合材料在不同温度下的强韧性能及其影响机制并建立相应的具有深刻物理背景的可计及使役温度影响的强韧性能与断裂行为的理论表征体系，具有十分重要的理论意义及工程应用背景。本项目首先研究了超高温陶瓷基复合材料在高温、高温氧化与热冲击等不同极端热环境下的温度相关性强韧性能及其影响因素，提出了一种可有效预测超高温陶瓷基复合材料体系的强韧性能与不同热环境、材料微结构及其演化之间的定量关系的表征方法，并进一步将该表征思想拓展应用到多孔陶瓷、混凝土等脆性材料的温度相关性断裂强度的研究。研究了强界面结合层状超高温陶瓷基复合材料温度相关性强韧性能及其影响因素，建立了可考虑使役温度、层内材料微结构及其演化以及不同层状结构共同影响的层间残余热应力与材料断裂强度理论表征模型，为强界面结合层状超高温陶瓷基复合材料温度相关性强韧性能提供了有效的评价表征方法。需要指出的是，本项目研究工作建立的材料温度相关性强韧性能系列理论表征模型所用到的材料基本参数如弹性模量、比热容等皆可很方便地通过实验或是材料手册直接获得，便于工程应用。基于建立的材料温度相关性强韧性能理论表征模型预测结果与实验研究结果，探索了不同温度下控制强界面结合层状超高温陶瓷基复合材料及其单层材料强韧性能的主要机制，揭示了材料在不同使役温度下的破坏形式及失效机理，进而基于微结构分析与控制、层状结构优化设计的思路提出了综合提高复合材料在不同温度下的力学性能的有效途径。在本项目的资助下，已在包括固体力学旗舰期刊Journal of the Mechanics and Physics of Solids、复合材料领域TOP期刊Composites Part B: Engineering、Composite Structures在内的国际期刊上发表SCI论文13篇，EI论文1篇，申请及授权发明专利4项。本项目研究成果可为进一步完善超高温结构材料体系以及优化高超声速飞行器热防护材料的设计提供理论指导与技术贮备。