|About this Abstract
||2016 TMS Annual Meeting & Exhibition
||Computational Thermodynamics and Kinetics
||Molecular Dynamics Study of Unexpected, Anisotropic Diffusion through Nickel-based Alloys and Oxides
||Penghui Cao, Michael Short, Daniel Wells
|On-Site Speaker (Planned)
The degradation and oxidation of nickel-based alloys are known problems for light water nuclear reactors (LWRs). A better understanding of the rates and mechanisms of oxide ingress and metal ion release would help to better predict corrosion and fouling rates in LWR cores. We have performed atomistic simulations to study cation and oxygen anion diffusion mechanisms in chromium oxides known to form in LWR conditions. We found that the concentration-dependent diffusivity is significant enough not to be neglected. In chromium oxide Cr2O3, four different point defects were investigated, and their corresponding temperature- and concentration-dependent diffusion coefficients were also computed Metal cations diffusion was found to be strong anisotropic at lower temperatures, which disappeared above 1800K. Migration energy barriers of point defects evaluated by Nudged Elastic Band (NEB) method show the origin of this anisotropic diffusion, and explain why it disappears at higher temperatures.
||Planned: A print-only volume