Microstructural Engineering of SiC-Si3N4 Nanocomposites Using a Combination of Classical Molecular Dynamics and Cohesive Finite Element Methods

结合经典分子动力学和内聚有限元方法进行 SiC-Si3N4 纳米复合材料的微观结构工程

• 批准号: 0961433
• 负责人: Vikas Tomar
• 金额: $ 6.01万
• 依托单位: Purdue University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-08-17 至 2010-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0961433&HistoricalAwards=false
• 关键词: Microstructural; Engineering; SiC; Si3N4; Nanocomposites

Silicon Carbide (SiC)-Silicon Nitride (Si3N4) nanocomposite material system consisting of nano-sized SiC reinforcements in a Si3N4 matrix is an important material system with excellent promise for use in high temperature structural systems. A fundamental theoretical understanding of the effect of nano-sized SiC reinforcements on the behavior of the composites is required before further attempting to improve the properties of these composites by varied morphological alterations. In this research such computational and theoretical microstructural engineering analyses for improved fracture strength will be performed with an explicit account of the multiple length scales associated with the second phase (SiC particles), the primary phase (Si3N4 matrix) and the grain boundaries (GBs), using the cohesive finite element method (CFEM). Since the second phase and the GBs involve nanoscopic lengthscales, the analyses will also focus on combining available experimental information with the corresponding classical molecular dynamics (MD) simulations for exploring differences in the fracture resistance prediction of various SiC-Si3N4 morphologies when the experimentally derived cohesive traction-separation relations are replaced by the atomistically derived ones. In view of the significant demand for new materials in advanced civil and mechanical systems such as advanced fossil fuel energy conversion systems, the developed analysis tool and analyses outcomes will represent a significant scientific and engineering milestone. The research will be integrated with K-12, undergraduate, and graduate educational enhancements, RET and REU program development, minority and underrepresented group involvement, new course development, and in-classroom teaching experience enhancement. The results of the research will be incorporated in the graduate and undergraduate solid mechanics courses being taught and in the micro-/nano-mechanics courses being developed. Lecture notes of the new courses taught and the research computer codes will be posted on the World Wide Web with user-friendly interfaces. Rising junior and senior high school women and students from underrepresented communities will be provided opportunities to explore technology, math, and science concepts using hands-on learning during summer time University campus visits.

碳化硅（SiC）-氮化硅（Si_3N_4）纳米复合材料是一种具有良好应用前景的高温结构材料。在进一步尝试通过不同的形态改变来改善这些复合材料的性能之前，需要对纳米SiC增强体对复合材料的行为的影响的基本理论理解。在这项研究中，这样的计算和理论的微观结构工程分析，提高断裂强度将执行与第二相（SiC颗粒），主相（Si 3 N4矩阵）和晶界（GB），使用凝聚力有限元法（CFEM）相关的多个长度尺度的明确帐户。由于第二阶段和GB涉及纳米尺度，分析也将集中在结合现有的实验信息与相应的经典分子动力学（MD）模拟探索不同的抗断裂性能预测的各种SiC-Si 3 N4形态时，实验得出的凝聚力牵引分离关系取代原子衍生的。鉴于先进的民用和机械系统（如先进的化石燃料能源转换系统）对新材料的大量需求，开发的分析工具和分析结果将代表一个重要的科学和工程里程碑。该研究将与K-12，本科和研究生教育增强，RET和REU计划开发，少数民族和代表性不足的群体参与，新课程开发和课堂教学经验增强相结合。研究结果将纳入正在教授的研究生和本科生固体力学课程以及正在开发的微/纳米力学课程。新课程的讲义和研究用电脑编码将张贴在万维网上，界面方便使用。来自代表性不足社区的初高中女生和学生将有机会在夏季大学校园参观期间通过实践学习探索技术、数学和科学概念。