Showing 1 - 10 of 11 Journals Results
2021
UKAEA-CCFE-PR(21)60
Andrew R. Warwick Max Boleininger Sergei L. Dudarev
Using atomistic simulations based on the creation-relaxation algorithm, we explore the evolution of microstructure in irradiated zirconium over a broad range of radiation exposure. In agreement with experimental observations, we find that at relatively low temperatures, microstructure evolves towards an asymptotic dynamic steady state forming at…
Preprint2021
UKAEA-CCFE-PR(21)56
Daniel R. Mason Fredric Granberg Max Boleininger Thomas Schwarz-Selinger Kai Nordlund Sergei L. Dudarev
Hydrogen isotopes are retained in materials for fusion power applications, changing both hydrogen embrittlement and tritium inventory as the microstructure undergoes irradiation damage. But modelling of the highly damaged regime – over 0.1 displacements per atom (dpa) – where asymptotic saturation is observed, is difficult because a highly dama…
Preprint2021
UKAEA-CCFE-PR(21)54
Pui-Wai Ma Sergei L. Dudarev
The concept of elastic dipole tensor of a defect is generalised to enable the treatment of lattice distortions, produced by defects at elevated temperatures. Thermodynamic and statistical mechanics derivations show the feasibility of computing the formation free energy and finite-temperature elastic dipole tensor of a $frac{1}{2}langle 111 rangle$ …
Preprint Published2020
UKAEA-CCFE-PR(20)113
Suchandrima Das Daniel R. Mason Peter M. Derlet Sergei L. Dudarev Andrew London Hongbing Yu Nicholas Phillips David Yang Kenichiro Mizohata Ruqing Xu Felix Hofmann
Combining spatially resolved X-ray Laue diffraction with atomic-scale simulations, we observe how ion-irradiated tungsten undergoes a series of non-linear structural transformations with increasing irradiation exposure. Nanoscale defect-induced deformations accumulating above 0.02 displacements per atom (dpa) lead to highly fluctuating strains at ~…
Preprint Published2020
UKAEA-CCFE-PR(20)105
Cameron McElfresh Yinan Cui Sergei Dudarev Giacomo Po Jaime Marian
Dislocation climb is an important high temperature process of metals plasticity, responsible for phenomena such as creep, swelling, or hardening. Climb is defined by the ability of dislocations to leave their original glide plane by interaction with point defects. As such, dislocation climb is controlled by point defect diffusion/absorption/emis…
Preprint Purchase2020
UKAEA-CCFE-PR(20)79
Jan S. Wrobel Marcin R. Zemla Duc Nguyen-Manh Par Olsson Luca Messina Christophe Domain Tomasz Wejrzanowski Sergei L. Dudarev
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 volume of a host Fe atom, whereas the volume of a substitutional Fe atom in antiferromagnetic…
Preprint Published2019
UKAEA-CCFE-PR(19)56
Max Boleininger Sergei L. Dudarev
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 Published2019
UKAEA-CCFE-PR(19)44
Daniel R. Mason Duc Nguyen-Manh Mihai-Cosmin Marinica Rebecca Alexander Sergei L. Dudarev
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 Published2019
UKAEA-CCFE-PR(19)43
Yang Li Max Boleininger Christian Robertson Laurent Dupuy Sergei L Dudarev
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 Published2019
UKAEA-CCFE-PR(19)17
Daniel Mason Andrea Sand Sergei Dudarev
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- 1
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