A novel ReaxFF multi-scale method for analyzing the fracture behavior of the CeO2

RZ Huang and Y Sun and ZQ Yang and YZ Liu and SF Yue, COMPUTATIONAL MATERIALS SCIENCE, 219, 112002 (2023).

DOI: 10.1016/j.commatsci.2022.112002

In this paper, a novel reactive force field (ReaxFF) multi-scale method is introduced to analyze the fracture behavior of cerium dioxide (CeO2) with a central crack. The ReaxFF multi-scale approach combining the ReaxFF molecular dynamics (MD) and the finite element method (FEM). The stress-strain curves of 11 1-oriented and 22 0-oriented models are calculated at room and medium-high temperature by the ReaxFF multi-scale method and the ReaxFF MD method. The results of the stress-strain curves of the two methods are in good agreement. Then, the diffusion of non- stoichiometric oxygen vacancy concentration in CeO2 under low oxygen partial pressure and uniaxial tensile loading is simulated. The non- stoichiometric oxygen vacancy concentration is higher at the crack tip than at other locations. A microscopic intermediate transition model is introduced to reduce the computational complexity when the ReaxFF multi- scale method is used to calculate the crack tip of macroscopic structure. In order to study the mechanism of generating non- stoichiometric oxygen vacancy con-centration at the surface of low oxygen partial pressure. The reaction between CeO2 and H2 is studied by the ReaxFF MD and the simulation results show that some of the oxygen atoms will escape from the CeO2, and hydroxyl groups form on the surface of CeO2.

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