SGER: Toughening Mechanisms of SiC/SiC Composites through SiC Nanowires

最近的实验表明，通过在基体中掺入极薄的陶瓷纤维或纳米线，可以大大提高某些高温陶瓷SiC/SiC复合材料的抗断裂性或韧性。纳米线-基体界面的特性控制了裂纹桥接和纤维拔出，这被认为是提高韧性的来源。为了描述和解释这种反应，该项目着重于内部核壳界面和纳米线与基体界面的变形机制的原子模拟。界面组成的优化有望为纳米线基陶瓷复合材料的强度、尺寸稳定性以及在核反应堆应用中的抗断裂和抗辐照性的设计提供指导。社会效益包括技术进步和研究生教育。研究结果将有助于开发适用于极端温度、强辐射和腐蚀的增韧复合材料。研究生的参与将有助于恢复核工业的人力需求。

Recent experiments have shown that fracture resistance or toughness of certain high-temperature ceramic SiC/SiC composites may be substantially elevated by incorporation of very thin ceramic fibers or nanowires into the matrix. Properties of the nanowire-matrix interface control crack bridging and fiber pullout, which are recognized as sources of the elevated toughness. To describe and explain this response, the project focuses on atomistic simulations of the deformation mechanisms at both internal core-shell interfaces and at interfaces of the nanowires with the matrix. Optimization of the interface composition is expected to provide guidelines for design of nanowire-based ceramic composites for strength, dimensional stability, and fracture and irradiation resistance in applications to nuclear reactors.Societal benefits include both technology advancement and graduate education. The results will enable the development of toughened composites for applications at extreme temperatures, intense radiation and corrosion. Involvement of a graduate student will contribute to manpower needs in the revival of the nuclear industry.