基于SLS技术成型SiCf/SiC点阵复合材料结构高温力学性能及损伤机理研究

针对近空间用高超声速飞行器热防护材料结构功能一体化的迫切要求，本项目重点突破3D打印制备高性能结构陶瓷的关键技术，采用选择性激光烧结技术和前驱体浸渍裂解技术相结合的方法研究轻质、承载和防隔热结构功能一体化的新型SiCf/SiC点阵复合材料结构。研究获得该点阵复合材料结构的制备工艺与微观组织结构，实验测试该复合材料的力学、热学参数及高温力学性能。基于细观力学、热弹性理论、热传导理论建立高温环境下SiCf/SiC点阵复合材料结构的热力耦合模型。通过数值模拟、实验研究、理论分析计算相结合的方法获得SiCf/SiC点阵复合材料结构强度设计准则与失效判据，揭示其高温环境下的失效机理。本项目属于前沿性的基础研究，其成果有望将为我国高超声速飞行器轻质多功能热防护材料的应用及安全评估提供理论支持与实验依据。

In order to fulfill the urgent requirement of structural and functional integration of thermal protective materials used in hypersonic aircrafts, this project aims to break through the key technology of 3D printing to fabricate high-performance structural ceramics. A new type of SiCf/SiC lattice composite structure with light weight, load-bearing and thermal insulation functions will be developed by combining selective laser sintering with precursor impregnation cracking. The fabrication process and microstructures of the lattice composites will be studied and established. The mechanical and thermal parameters as well as high temperature mechanical performance of the composites will be experimental tested. Besides, based on meso-mechanics, thermoelasticity and heat conduction theory, the thermo-mechanical coupling model of SiCf/SiC lattice composite structure under high temperature will be established. The strength criteria and failure criteria will be obtained by numerical simulation, experimental characterization and theoretical analysis, and the failure mechanism under high temperature will be revealed. This project focuses on the frontier basic research, and the development of this project will provide theoretical support and experimental basis to the application and safety assessment of light multi-functional thermal protective materials for hypersonic vehicles in China.