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.
