Effect of Nanostructure on High Temperature Tensile Strength of Amorphous SiCN Ceramics: A Large-Scale Molecular Dynamics Study

In this study, atomistic simulations were applied to study the mechanical properties of SiCN at high temperature tensile strain. The atomistic structures obtained by large-scale molecular dynamics simulations agree with current experimental results, and provide more details on high temperature mechanical properties of SiCN. The interface of Si3N4 region and free carbon in SiCN is not the unique location of fracture, which means that the domain interfaces in SiCN are strong. Si3C7N4 presents the largest Young's modulus at all temperatures, which is attributed to the network structure of free carbon. The three-dimensional free carbon network results in stable Young's modulus at high temperatures, and it gives an explanation for excellent thermal stability of SiCN.