High Temperature Strengths and Deformation of Ceramics

Abstract

Abstract : This project developed a computational modeling capability to study the theoretical strengths and deformation mechanisms of structural ceramics for high temperature applications. The approach adopted was molecular dynamics simulation based on appropriate interatomic potential models. The studies focused on ZrC that has excellent high-temperature properties, and to a lesser extent on SiC and SiO2. Strain-to-failure simulations were performed to observe the details of the structural instability and subsequent microstructural evolution. Besides single crystals, deformations in the amorphous and nanocrystalline phases were also investigated. In parallel elastic stiffness and other mechanical properties were calculated to correlate with and interpret the simulation results. The research performed in this project has demonstrated the feasibility of modeling the intrinsic mechanical and thermal properties of ceramics. The results obtained contribute to a database of structure-property correlation that provides a foundation for further computational studies of ceramics for high temperature applications. It appears that modeling and simulation at the atomistic level have reached a level of physical robustness that one can begin to develop detailed understanding of certain ceramics under conditions of practical interest.