Molecular dynamics study of hydrogen isotopes at the Be/BeO interface

Abstract

Molecular dynamics simulations are used to investigate the behaviour of D atoms at two interfaces between Beryllium (Be) and Beryllium oxide (BeO). After relaxation of the simulation cell, there are (i) localised defects at the interface and (ii) a hexagonal misfit dislocation network creating a succession of compressed and expanded area from each side of the interface. The simulations between 750 K and 1500 K for tens to hundreds of nanoseconds show that both interfaces act as trapping sites for D atoms. The simulations also show that D atoms tend to migrate in the material where the H solubility is the highest as predicted by thermodynamics. However, the simulations also shows that there are additional kinetic barriers (D trapping sites, D2 formation/dissociation in BeO) that slow down the path to equilibrium. These additional kinetic barriers may influence the fuel retention and permeation in Be materials.

Molecular Dynamics Simulation of High Temperature Mechanical Properties of Nano-Polycrystalline Beryllium Oxide and Relevant Experimental Verification

“…The MD simulations are implemented using the open-source software LAMMPS [6,7]. J. Byggmästar and E. A. Hodille et al developed the interatomic potential for BeO [8][9][10][11], which is based on the Tersoff potential function [12,13]. The tensile test is performed along the X axis with a deformation rate of 1 nm/ps.…”