First-principles investigation of intrinsic defects and self-diffusion in ordered phases of V₂C
The self-diffusion behavior of vanadium subcarbide (V2C) is investigated using density functional theory calculations, owing to its potential application as a diffusion barrier in nuclear applications. Three ordered V2C structures, two of which correspond to experimentally observed phases, are characterized in terms of their equilibrium structural, electronic and elastic properties. Our model for self-diffusion in V2C considers diffusion of carbon and vanadium to occur separately on each sublattice. Two sets of self-diffusion coefficients are calculated for each structure: one for vacancy-mediated diffusion of vanadium and the other for interstitial diffusion of carbon. Calculated activation energies and diffusion prefactors are compared to experimental data for the cubic transition metal carbides as there is no experimental self-diffusion data for any of the hexagonal subcarbides.
B. J. Demaske et al., "First-principles investigation of intrinsic defects and self-diffusion in ordered phases of V₂C," Journal of Physics Condensed Matter, vol. 29, no. 24, Institute of Physics - IOP Publishing, May 2017.
The definitive version is available at https://doi.org/10.1088/1361-648X/aa7031
Center for High Performance Computing Research
Keywords and Phrases
Density Functional Theory; Phonons; Point Defects; Self-diffusion; Vanadium Carbide
International Standard Serial Number (ISSN)
Article - Journal
© 2017 Institute of Physics - IOP Publishing, All rights reserved.
01 May 2017
This work was supported by a DOE NEUP Award (DE-NE0000731). BJD was also supported by the Department of Defense (DoD) through the National Defense Science and Engineering Graduate Fellowship (NDSEG) Program.