Showing 1 - 10 of 97 Journals Results
2021
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 Published2021
UKAEA-CCFE-PR(21)33
K. Arakawa Z. Bergstrom M.J. Caturla S.L. Dudarev F. Gao M.R. Gilbert A.M. Goryaeva S.Y. Hu X. Hu R.J. Kurtz A. Litnovsky J. Marian M.-C. Marinica E. Martinez E.A. Marquis D.R. Mason B.N. Nguyen P. Olsson Y. Osetskiy D. Senor
Prediction of material performance in fusion reactor environments relies on computational modelling, and will continue to do so until the first generation of fusion power plants come on line and allow long-term behaviour to be observed. In the meantime, the modelling is supported by experiments that attempt to replicate some aspects of the eventua…
Preprint Published2021
UKAEA-CCFE-PR(21)01
M. Boleininger M. Gallauer S. L. Dudarev T. D. Swinburne D. R. Mason D. Perez
The ability of a body-centered cubic metal to deform plastically is limited by the thermally activated glide motion of screw dislocations, which are line defects with a mobility exhibiting complex dependence on temperature, stress, and dislocation segment length. We derive an analytical expression for the velocity of dislocation glide, based on a s…
Preprint2020
UKAEA-CCFE-PR(20)141
Pui-Wai Ma S L Dudarev
Using ab initio density function theory calculations, we have determined the structure of self-interstitial atom (SIA) defects in the most commonly occurring face-centred cubic (FCC) metals. The most stable SIA defects in Al, Ca, Ni, Cu, Pd and Ag are the {100} dumbbells whereas octahedral SIA configurations have the lowest energy in Pt, R…
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)108
Pui-Wai Ma D. R. Mason S. L. Dudarev
We performed ab initio density functional theory simulations of 1/2{111} interstitial dislocation loops, closed and open vacancy loops, {100} interstitial loops and voids in tungsten, using simulation cells involving from 2000 to 2700 atoms. The size of the loops transcends the microscopic scale and reaches the mesoscopic scale where as…
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 Published2020
UKAEA-CCFE-PR(20)74