Journals

Showing 1 - 7 of 7 Journals Results
2020
UKAEA-CCFE-PR(20)79

Point defects in body-centred cubic Fe, Cr and concentrated random magnetic Fe-Cr are investigated

using density functional theory and theory of elasticity. The volume of a substitutional

Cr atom in ferromagnetic bcc Fe is approximately 18% larger than the…

Preprint
2019
UKAEA-CCFE-PR(19)56

Linear elasticity theory predicts a divergent strain field at the dislocation core, resulting from the continuum approximation breaking down at the atomic scale. We introduce a minimum model that includes elastic interactions and discrete lattice periodicity, and derive a set of equations that treat the core of an edge dislocation from a solely geo…

Preprint Published
2019
UKAEA-CCFE-PR(19)44

The low energy structures of irradiation-induced defects have been studied in detail, as these determine the available modes by which a defect can diffuse or relax. As a result, there are many studies concerning the relative energies of possible defect structures, and empirical potentials are commonly fitted to or evaluated with respect to these en…

Preprint Published
2019
UKAEA-CCFE-PR(19)43

Body-centered cubic metals and alloys irradiated by energetic particles form highly mobile prismatic dislocation loops with a/2 {111} -type Burgers vectors. We show how to simulate thermal diffusion of prismatic loops using a discrete dislocation dynamics approach that explicitly includes the stochastic forces associated with ambient thermal fluctu…

Preprint Published
2019
UKAEA-CCFE-PR(19)17

We describe the development of a new object kinetic Monte Carlo code where the elementary defect objects are off-lattice atomistic configurations. Atomic-level transitions are used to transform and translate objects, to split objects and to merge them together. This gradually constructs a database of atomic configurations- a set of relevant defect …

Preprint Published
2019
UKAEA-CCFE-PR(19)15

Vacancy formation and migration control self-diffusion in pure crystalline materials, whereas irradiation produces high concentrations of vacancy and self-interstitial atom defects, exceeding by many orders of magnitude the thermal equilibrium concentrations. The defects themselves, and the extended dislocation microstructure formed under irradiati…

Preprint Published
2016
CCFE-PR(16)39

Vacancy-mediated climb models cannot account for the fast, direct coalescence of dislocation loops seen experimentally. An alternative mechanism, self climb, allows prismatic dislocation loops to move away from their glide surface via pipe diffusion around the loop perimeter, independent of any vacancy atmosphere. Despite the known importance of se…

Preprint Published