Cf/ZrB2-SiC-Hf仿生复合微结构构筑及增韧机制研究

Ultra-high temperature ceramics are a kind of non-ablation type thermal protection materials with great potential in extreme thermal oxidation environments, but the intrinsic brittleness of ceramic materials severely limits their engineering applications. The project will take ZrB2 ultra-high temperature ceramics as the research object, and improve the damage tolerance of ZrB2 ceramics through the ceramic-metal "brick-mortar" and fiber helicoidal biomimetic composite microstructure. Refractory metal Hf will be used as the compliant phase of ceramic-metal "brick-mortar" structure, a heterogeneous precipitation and high temperature thermal reduction process will be used to coat ZrB2-SiC composite powder with Hf, and the technology and mechanism of adjusting and controlling surface metal morphology on the composite powder will be investigated. Hf-coated ZrB2-SiC composite powder and carbon fiber coated with carbon coating are used to construct fiber/ceramic-metal helicoidal structural materials through dual-channel coextrusion molding and low-temperature hot-pressing. The influence of the grain boundary on the fracture mode of the ceramic-metal "brick-mortar" microstructure and the effect of fiber helicoidal structure on the crack growth behavior of composite materials will be investigated, and revealing the toughening mechanism of biomimetic composite microstructures. A technological breakthrough will be made in the construction process of ultra-high temperature ceramic biomimetic composite microstructure, and a novel type of high-toughness ultra-high temperature ceramic composite material will be developed to provide a theoretical basis and lay a technical foundation for the engineering application of non-ablation thermal insulation materials in major national strategic needs.

超高温陶瓷是应用于极端热氧化环境中较具潜力的一种非烧蚀型防热材料，但陶瓷材料的本征脆性限制了其工程应用。项目以ZrB2超高温陶瓷为研究对象，通过陶瓷-金属“砖-泥”和纤维螺旋仿生复合微结构提升ZrB2陶瓷的抗损伤容限。采用难熔金属Hf作为陶瓷-金属“砖-泥”结构的屈服相，利用非均相沉淀-热还原工艺在纳米ZrB2-SiC复合粉体表面包覆金属Hf，研究复合粉体表面金属形貌调控技术及机理。采用Hf包覆的ZrB2-SiC复合粉体与碳涂层包覆的碳纤维通过双通道共挤出成型和低温热压烧结构筑纤维/陶瓷-金属螺旋结构材料。研究晶界相对陶瓷-金属“砖-泥”结构断裂模式的影响，研究纤维螺旋结构对复合材料裂纹扩展行为的影响，揭示仿生复合微结构增韧机制。在超高温陶瓷仿生复合微结构构筑工艺取得技术突破，开发出新型高韧性超高温陶瓷复合材料，为非烧蚀防热材料在国家重大战略需求中的工程化应用提供理论依据并奠定技术基础。

内容获取失败，请点击重试