非均匀分布SiC增强铝合金复合材料的增强与增韧机制研究

Taking an overview of the worldwide research in discontinuous metal matrix composites (DMMCs), despite many favourable attributes such as improved specific strength and superior wear resistance, DMMCs with a homogeneous microstructure tend to exhibit a very low room temperature damage tolerance and result inevitably in limited stiffness close to the lower bound of Hashin and Shtrikman model. In order to explore the potential properties of DMMCs, composites with inhomogeneous mesostructures attracts a lot of attention of worldwide scientists. However, due to the complicated mesostructure and multiple scale of inhomogeneous composites, so far most studies are focused on experimental preparation and test, without theoretical guidance or systematic numerical analysis on the relationship between the macromechanical properties and mesostructures. This research project aims to address these issues through both experimental and modeling efforts. A series of mesomechanical models will be developed for four types of inhomogeneous DMMCs according to 3D phase connectivity, i.e. Isolated reinforcement-rich phase (0D), Bar-like reinforcement-rich phase (1D), laminated reinforcement-rich phase (2D) and bi-continuous reinforcement-rich and reinforcement-lean phase(3D), to investigate the influences of different mesoscopic characteristic parameters on the mechanical properties and behaviors of DMMCs quantitatively. Moreover, systematic experiments will also be carried out to validate the simulation results. Through feedbacks between the simulations and experiments, the optimal mesoostructure of inmomogeneous SiC/Al composites will be made under different loads, which will have significant meanings for the development and application of light, strong and multifunctional advanced composites.

纵观世界范围在非连续金属基复合材料方面的研究现状，尽管展现了优良比强度及超好的耐磨性，但含均匀细观结构的复合材料显示出很差的室温损伤容限及刚度靠近Hashin-Shtrikman模型预测下限。为了开发非连续金属基复合材料的潜能，含非均匀细观结构的复合材料正吸引着全世界科学家的关注。由于非均匀复合材料细观结构的复杂性与多尺度性，目前的研究主要集中在材料制备方面的尝试，尚缺乏理论的指导和系统的实验研究。本项目从数值模拟与实验两个方面来研究非均匀复合材料的增强与增韧机制。针对离散型增强相(0D),线型增强相（1D）,层型增强相（2D）和双连续性结构（3D）四类非均匀复合材料，我们将采用计算细观力学和实验制备与测试相结合来研究细观非均匀结构对复合材料力学性能的影响。我们还将进行一系列实验来验证模拟结果。通过模拟和实验之间的不断反馈，实现该材料的微观结构优化，加速我国先进复合材料的研发进程。

纵观世界范围在非连续金属基复合材料方面的研究现状，尽管展现了优良比强度及超好的耐磨性，但含均匀细观结构的复合材料显示出很差的室温损伤容限及刚度靠近Hashin-Shtrikman模型预测下限。为了开发非连续金属基复合材料的潜能，含非均匀细观结构的复合材料正吸引着全世界科学家的关注。由于非均匀复合材料细观结构的复杂性与多尺度性，目前的研究主要集中在材料制备方面的尝试，尚缺乏理论的指导和系统的实验研究。本项目从数值模拟与实验两个方面来研究非均匀复合材料的增强与增韧机制。针对离散型增强相(0D),线型增强相（1D）,层型增强相（2D）和双连续性结构（3D）四类非均匀复合材料，我们采用计算细观力学和实验制备与测试相结合来研究细观非均匀结构对复合材料力学性能的影响。通过开发的一系列程序，由一系列随机数序列控制增强相颗粒形状、尺寸、位置及排列方向。通过控制随机数的种子来改变复合材料的细观结构，进而研究不同载荷条件下，考虑了增强相的脆性断裂，基体的延性失效行为及界面开裂行为，细观结构对复合材料力学性能的影响规律。为制备具有优良力学性能的复合材料提供理论指导。该项目中开发的系列程序不仅可以用于金属基复合材料，也可以用于生成其它各种复合材料的细观结构，为复合材料的计算细观力学提供有效工具。