碳/碳和钛合金钎缝吸能复合结构的材料本构及多维界面动态冶金行为研究

C/C与钛合金钎焊技术在超音速和高超音速飞行器中有远大前景，减缓高残余热应力是大面积接头制备的技术瓶颈。本项目基于泡沫金属结构功能一体化特性，采用其作为吸能中间层钎焊C/C和钛合金。测试钎缝吸能复合结构的力学响应，结合材料本构理论，探索其材料本构关系；在此基础上，采用数值仿真技术模拟接头钎焊过程中的应力演变，并提出吸能中间层设计原则和优选准则。采用高分辨高速摄影观测、显微分析与热力学、扩散和冶金反应推导相结合，探索接头各反应界面和泡沫金属胞孔内部宏-细观、多维度、动态冶金反应过程和界面组织演变；损伤电测法和显微观测相结合，探索高低温热循环或疲劳载荷-裂纹萌生扩展-电阻应变的量化关系，研究接头在疲劳载荷下的损伤机理。发展大面积、高性能C/C与钛合金的钎焊技术，为推动C/C在航空航天产业中应用提供技术支持。

The brazing technology of C/C and titanium alloy has a bright prospect in the field of supersonic and hypersonic aircraft. The residual stress relieving is a main difficulty during brazing with large bonding area. In this project, based on the functional and structural properties of metal foam, C/C and titanium alloy is brazed with metal foam as an energy absorbing interlayer. Combining mechanical response of the absorbing composite structure and the constitutive theories of materials, the constitutive relation of the absorbing composite structure will be studied. The stress evolution of the joint in the brazing process is simulated, and the optimal design and selection principles of the energy absorption interlayer are proposed. High speed photographical observation, microscopic analysis, thermodynamic calculation, diffusion and metallurgical reaction deduction are used to study the macro-meso, multi-dimension, dynamic metallurgical reaction inside the foam cell and the interfaces, consequently, the interfacial microstructure evolution mechanism of the joint will be proposed. The damage electrometric method with microscopic observation is adopted to study the quantitative relationship between fatigue load- crack initiation and propagation-resistance strain and conclude the damage mechanism of the joint. Large area, high performance C/C and titanium alloy brazing technology will promote and support the application of C/C in the aerospace industry.