原位自生TiB2/Al复合材料微观结构及强化机理跨尺度量化分析研究

The in-situ grown particles renforced composites have great potential in the fields of military defense, aerospace and microelectronic industry due to its outstanding properties. Unlike the ex-situ particles renforced composites, the characteristics, size and volume distribution functions of these in-situ grown particles are unknown and very difficult to be characterized. However, these properties and distribution functions have great influences on the mechanical properties of composites and its mechanism is still unknown. At macroscopic scale, the small angle neutron scattering (SANS) will be carried out to characterize the in-situ grown particles properties and distribution functions in the composites.The in-situ neutron diffraction analysis will be taken, at mesoscopic scale, on the composites under uniaxial tension load, in order to measure stress-strain relationships relative to each phase, to study the intergranular and interphase stress development. The interaction mechanism of different grains and phases will be discussed. At microscopic scale, the high resolution transmission electron microscope (HRTEM) analysis will be carried out to study the particles/matrix interface characters (such as the crytalline orientation relationship, the local chemical composition, the local internal stresses et al). The effects of interface characteristics on the mechanical properties will be studied. The strenthen mechanism of the in-situ grown particles renforced composites will be proposed with the use of a multi-scale model (from microscale to macroscale ). Thus, our research will improve the design and synthesis of the new in-situ grown particles renforced composites with excellent properties.

原位自生铝基复合材料是一种具备巨大应用前景的复合材料，但由于原位自生铝基复合材料内部增强相特征和分布函数难以定量表征；并且其增强相特征、增强相分布函数及基体/颗粒界面对复合材料的宏观性能的作用机理目前并不清楚，这些因素严重制约了原位自生铝基复合材料的研究与应用。本项目通过中子小角度散射（SANS）技术从宏观上表征上述体系第二相分布函数并研究其与宏观力学性能的关系，通过动态单向拉伸状态下实时中子衍射应力测试技术选择性地从亚宏观尺度上实测颗粒相与基体相各自的应力-应变本构关系、研究两相内部相互作用关系、及颗粒对基体强化机理。微观上通过HRTEM研究上述体系颗粒在凝固结晶中的分布规律和与合金元素的关系，以及两相界面的组合模式、位相关系、共格关系、微区成分、界面微区内应力等与宏观性能的关系。通过从宏观到亚宏观到微观的跨尺度研究认识增强相强化机理，指导新型复合材料的设计与制备。

原位自生铝基复合材料是一种具备巨大应用前景的复合材料，但由于原位自生铝基复合材料内部增强相特征和分布函数难以定量表征；并且其增强相特征、增强相分布函数及基体/颗粒界面对复合材料的宏观性能的作用机理目前并不清楚，这些因素严重制约了原位自生铝基复合材料的研究与应用。本项目通过中子小角散射，中子/同步辐射线性分析技术从宏观上研究了上述体系第二相分布函数以及其与宏观力学性能的关系，通过中子衍射织构分析技术结合电子背散射技术定量研究了第二相陶瓷颗粒对复合材料塑性变形材料微结构演化的影响规律，已经这种微结构演化对材料宏观力学性能的影响。 微观上通过HRTEM研究上述体系颗粒在凝固结晶中的分布规律和与合金元素的关系，以及两相界面的组合模式、位相关系、共格关系等与宏观性能的关系。结合动态拉伸状态下中子衍射应力分析技术选择性地从亚宏观尺度上实测颗粒相与基体相各自的应力-应变本构关系、研究了两相内部相互作用关系、及颗粒对基体强化机理。通过从宏观到亚宏观到微观的跨尺度研究了增强相强化机理，为新型复合材料的进一步提升性能提供了理论支持。