金属基复合材料网状构型设计与优化

在传统的增强体均匀分布复合材料中，不可避免的出现强韧性倒置的问题。本项目通过引入增强相网状构型设计强韧化复合材料。旨在探索一种数值模拟指导金属基复合材料构型设计及优化的研究方法。本项目采用全新的建模技术，构建颗粒/晶须按类晶界结构排列的多元胞网状构型复合材料几何模型，对其在拉伸和弯曲载荷作用下的变形和断裂行为进行仿真。阐明构型化复合材料变形过程中应力-应变分配和能量耗散的跨尺度力学原理，解决网状构型结构参数对复合材料变形、断裂行为和力学性能影响的问题。采用数值模拟结合原位拉伸试验、断口分析、同步辐射观察微裂纹形貌的办法，揭示铝基/钛基复合材料塑性变形、裂纹萌生扩展行为与材料强韧化机制。总结网状构型设计与优化准则。为网状构型金属基复合材料的设计、制备及应用提供理论基础与试验依据。

In the homogeneous composites, the inversion between strength and toughness is inevitable. A viable solution of strengthening and toughening metal matrix composites (MMCs) is reinforcement network architecture design. The project aims to explore a novel numerical simulation method, in order to guide the network architecture design and optimization of metal matrix composites. A new modeling technique will be adopted to construct geometry model of the composite, in which particles/whiskers align with grain-liked multi-cell network architecture. The crystal plasticity theory will be introduce to describe deformation behavior of matrix grain. Then the deformation and fracture behavior of network composites can be simulated with tensile and bending loads. The cross-scale mechanics principle of stress/strain distribution and energy dissipation will be expounded. The effect of structural parameters on the deformation, fracture behavior and mechanical properties of composites will be investigated. Numerical simulation combined with in-situ tensile test, fracture surface analysis and synchrotron radiation observation on microcrack morphology will be applied to reveal the mechanisms of plastic deformation, crack initiation/propagation and mechanism of strengthening and toughening in aluminum/titanium matrix composites with network architecture. The design and optimization of network architecture will be summarized, to provide useful insight into the design, fabrication and engineering application of this new class of MMCs.