Showing 1 - 10 of 93 Journals Results
2020
UKAEA-CCFE-PR(20)141
Pui-Wai Ma S L Dudarev
Using textit{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 $langle 100rangle$ dumbbells whereas octahedral SIA configurations have the lowest ene…
Preprint2020
UKAEA-CCFE-PR(20)128
P M Derlet S L Dudarev
It has been long hypothesized that the structure of a material bombarded by energetic particles might approach a certain asymptotic steady state in the limit of high exposure to irradiation. There is still no de nitive verdict regarding the validity of this hypothesis or the conditions where it applies. To clarify this, we explore a highly simpl…
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 fluctuat…
Preprint2020
UKAEA-CCFE-PR(20)108
Pui-Wai Ma D. R. Mason S. L. Dudarev
We performed textit{ab initio} density functional theory simulations of $frac{1}{2}langle 111 rangle$ interstitial dislocation loops, closed and open vacancy loops, $langle 100rangle$ 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…
Preprint2020
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/emissi…
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…
Preprint2020
UKAEA-CCFE-PR(20)74
A. De Backer C. Domain C.S. Becquart L. Luneville D. Simeone A. E. S K. Nordlund
The impacts of ions and neutrons in metals causes cascades of atomic collisions that expand and shrink, leaving microstructure defect debris, i.e. interstitial or vacancy clusters or loops of different sizes. In [A. De Backer, A. E. Sand, K. Nordlund, L. Lun´eville, D. Simeone, and S. L. Dudarev. EPL, 115(2):26001, 2016.], we described a method…
Preprint Published2020
UKAEA-CCFE-PR(20)73
I. Rovelli S.L. Dudarev A.P. Sutton
The evolution of the defect microstructure in materials at high temperature is dominated by diffusion-mediated interactions between dislocations, vacancy clusters and surfaces. This gives rise to complex non-linear couplings between interstitial and vacancy-type dislocation loops, cavities and the field of diffusing vacancies t…
Preprint Published2020
UKAEA-CCFE-PR(20)72
A. Hollingsworth M.-F. Barthe Z. Hu P. Desgardin M.Yu. Lavrentiev S.L. Dudarev P. Derlet D. Mason J. Hess S. Davies B. Thomas H. Salter E.F.J. Shelton K. Heinola K. Mizohata A. De Backer A. Baron-Wiechec I. Jepu E. Zayachuk A. Widdowson E. Meslin A. Morellec
Self-ion bombardment of pure tungsten with ion energies of 2 MeV is used to mimic the defects created by neutrons in a fusion reactor. Electron microscopy is used to characterize the microstructure of samples. Thermal Desorption Spectrometry (TDS) is performed on deuterium implanted samples in order to estimate deuterium inventory as function of da…
Preprint2020
UKAEA-CCFE-PR(19)15