M. Boleininger T. D. Swinburne S. L. Dudarev
Conventional linear elasticity theory predicts the strain fields of a dislocation core to diverge, whereas it is known from atomistic simulations that strains at dislocation cores remain finite. We present an analytical solution to a generalised, variational Peierls-Nabarro model of edge dislocation displacement fields that features a finite core w…
Preprint PublishedD.R. Mason X. Yi A.E. Sand S.L. Dudarev
We present a new analysis of nanoscale lattice defects observed after low-dose in situ self-ion irradiation of tungsten foils at cryogenic temperature. For decades, defect counts and size-frequency histograms have been the standard form of presenting a quantitative analysis of the nanoscale “black-dot” damage typical of such irradiations. Here …
Preprint PublishedI. 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 that adiabatically fol…
Preprint PublishedT. D. Swinburne S. Dudarev
The line tension model of obstacle hardening is modified to account for the thermally activated, kink-limited glide of 1=2h111i screw dislocations, allowing application to the plastic flow of bcc metals. Using atomistically-informed dislocation mobility laws, Frenkel-Kontorova simulations and a simplified dislocation obstacle model, we identify a …
Preprint PublishedS. L. Dudarev Pui-Wai Ma
Density functional theory (DFT) calculations show that self-interstitial atom defects in nonmagnetic body-centred cubic (bcc) metals adopt strongly anisotropic configurations, elongated in the h111i direction1–4. Elastic distortions, associated with such anisotropic defect configurations, appear similar to the distortions around small prismatic d…
Preprint PurchaseA. De Backer D.R. Mason C. Domain D. Nguyen-Manh M.-C. Marinica L. Ventelon C.S. Becquart S.L. Dudarev
In a fusion tokamak, the plasma of hydrogen isotopes is in contact with tungsten at the surface of a divertor. In the bulk of the material, the hydrogen concentration profile tends towards dynamic equilibrium between the flux of incident ions and their trapping and release from defects, either native or produced by ion and neutron irradiation. The …
Preprint PublishedD.R. Mason A.E. Sand X. Yi S.L. Dudarev
Recently we have presented direct experimental evidence for large defect clusters being formed in primary damage cascades in self-ion irradiated tungsten [Yi et al., EPL 110:36001 (2015)]. This large size is significant, as it implies th…
Preprint PurchaseM.Y. Lavrentiev D. Nguyen-Manh S.L. Dudarev
Using an ab initio approach, we explore the stability of small vacancy and vacancychromium clusters in dilute body-centred cubic Fe-Cr alloys. To explain experimental observations described in C.D. Hardie et al., J. Nucl. Mater. 439, 33 (2013) and showing the occurrence of Cr segregation in low-Cr alloys, we investigate if chromium can form stable …
Preprint PublishedT. D. Swinburne P. W. Ma S. L . Dudarev
The low temperature diffusivity of nanoscale crystal defects, where quantum mechanical fluctuations are known to play a crucial role, are essential to interpret measurements of irradiated microstructures conducted at cryogenic temperatures. Using density functional theory calculations, quantum heat bath molecular dynamics and open quantum systems t…
Preprint PublishedK. Arakawa M. Marinica S. Fitzgerald L. Proville D. Nguyen-Manh S.L Dudarev P. Wai Ma T.D Swinburne T. Yamada T. Amino S. Arai Y. Yamamoto K. Higuchi N. Tanaka H. Yasuda T. Yasuda H. Mori
Quantum dynamics within solids is usually restricted to low mass particles such as electrons and muons, or single atoms of light elements such as hydrogen. In this letter we report observation of the quantum-assisted motion of self-interstitial atom clusters in tungsten (each of mass 184 Da), travelling distances of several nanometres between trapp…
Preprint