Molecular dynamics study of the point defects in bcc uranium
نویسندگان
چکیده
Thermodynamic properties of bcc uranium with point defects are studied using ab initio molecular dynamics (MD) simulations at 1100 K. The were performed canonical ensembles ${\mathrm{U}}_{127}{\mathrm{M}}_{1}$, ${\mathrm{U}}_{128}{\mathrm{M}}_{1}$, and ${\mathrm{U}}_{126}{\mathrm{M}}_{1}{\ensuremath{\square}}_{1}$ for M = $\ensuremath{\square}$, He, Ne, Ar, Kr, Xe, Sr, Zr, I, Cs, Pu disposed on a lattice lying within $4\ifmmode\times\else\texttimes\fi{}4\ifmmode\times\else\texttimes\fi{}4$ cubic supercell. This work provides formation energies substitutional, self, solute interstitial atom as well binding M-$\ensuremath{\square}$ pair defects. demonstrates that our computational scheme based MD gives reliable atomic in compared to conventional density functional theory calculations. equilibrium volume, bulk modulus, thermal expansion coefficient pure obtained from compare very corresponding experimental results. vacancy energy is predicted be 0.88 eV. remains uncertain. Experimental study the other modulus coefficients these also not found literature. shows tend decrease increase uranium. noble gas atoms show bearing their size. A large (Xe) has high energy, vice versa. size effect quite evident chemically reactive solutes, namely, Pu. Our further vacancies favorable rather than both self interstitials by earlier lower those atoms, each calculated six different basic dumbbell configurations. That is, U accommodates more easily decay or fission (He, Xe). Further, He have comparable substitutional locations. product Kr Xe prefer occupy vacant sites sites. Binding divacancy solute-vacancy pairs (0.31 vs $\ensuremath{-}0.69$ eV Xe-$\ensuremath{\square}$ pair, instance) simulation nucleation growth bubbles supported thermodynamic driving force, whereas stay apart. agreement literature reporting softens swells mainly agglomeration bubbles.
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ژورنال
عنوان ژورنال: Physical Review Materials
سال: 2021
ISSN: ['2476-0455', '2475-9953']
DOI: https://doi.org/10.1103/physrevmaterials.5.053604