Molecular dynamics investigation of structure and high-temperature mechanical properties of SiBCO ceramics

NB Liao and W Xue and HM Zhou and M Zhang, JOURNAL OF ALLOYS AND COMPOUNDS, 610, 45-49 (2014).

DOI: 10.1016/j.jallcom.2014.04.189

SiCO ceramics present excellent properties at high temperatures, the addition of boron for SiCO leads to enhanced performance on thermal stability and creep temperature. Investigating atomic structure and its influence on material property are essential for further study. In this study, large-scale molecular dynamics simulations were used to study amorphous SiBCO structures with different carbon contents. Phase separation and free carbon structures were successfully reproduced by melt-quench simulation. The calculated pair distribution functions of SiBCO are comparable to those of SiCO in experiments, the C-C-C angular distribution indicates strong sp(2) carbon character together with a sp(3) character. Si-centered tetrahedrons present in amorphous SiBCO and the most popular case is Si-C/O tetrahedron. Si3BC7O3 presents the largest Young's modulus for all the temperatures due to the network structure of free carbon. A change in the slope of temperature-dependent Young's moduli at 1300 K-1700 K for Si3BC7O3 indicates the glass transition temperature. (C) 2014 Elsevier B.V. All rights reserved.

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