UKAEA Papers

"An empirical potential to simulate helium and hydrogen in irradiated tungsten, with a mechanistic model for hydrogen retention in gas-filled voids"

• Samanyu Tirumala
• Daniel Mason
• Oliver Shattock
• Duc Nguyen-Manh
• Felix Hofmann
• Max Boleininger

Materials used in commercial D-T fusion reactors will be exposed to irradiation and a mixture of helium and hydrogen plasma. Modeling the microstructural evolution of such materials requires the use of large-scale molecular dynamics simulations. The focus of this study is to develop a fast EAM potential for the interactions among the three elements…

"Simulated TEM imaging of a heavily irradiated metal"

• Daniel R. Mason
• Max Boleininger
• Jack Haley
• Eric Prestat
• Guanze He
• Felix Hofmann
• Sergei L. Dudarev

We recast the Howie-Whelan equations for generating simulated transmission electron microscope (TEM) images, replacing the dependence on local atomic displacements with atomic positions only. This allows very rapid computation of simulated TEM images for arbitrarily complex atomistic configurations of lattice defects and dislocations in the dyna…

"Simulations of Nanocrystalline Iron Formation under High Shear Strain"

• Ivan Tolkachev
• Felix Hofmann
• Pui-Wai Ma

High-shear methods have long been used in experiments to refine grain structures in metals, yet the underlying mechanisms remain elusive. We demonstrate a refinement process using molecular dynamic simulations, wherein nanocrystalline structures are generated from initially perfect lattices under high-shear strain. The simulation cells undergo a hi…

"An estimate for thermal diffusivity in highly irradiated tungsten using Molecular Dynamics simulation"

• Daniel R. Mason
• Abdallah Reza
• Fredric Granberg
• Felix Hofmann

The changing thermal conductivity of an irradiated material is among the principal design considerations for any nuclear reactor, but at present few models are capable of predicting these changes starting from an arbitrary atomistic model. Here we present a simple model for computing the thermal diffusivity of tungsten, based on the conductivity…

"Observation of transient and asymptotic driven structural states of tungsten exposed to irradiation"

• 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 ~…

"Origin of Early Continental Crust by Reworking Silicified Metabasalts"

• Luc Andre
• Kathrin Abraham
• Axel Hofmann
• Laurence Monin
• Ilka C. Kleinhanns
• Stephen Foley

How the Archean felsic crust grew from its mafic precursors between 3.8 and 2.5 billion years ago remains elusive and the subject of great debate. Here, we present silicon isotopic constraints on Tonalite-Trondhjemite-Granodiorite (TTG) and Granite-Monzonite-Syenite (GMS) plutons from the Kaapvaal craton, which range in age from 3.55 to 2.69 Ga.…

"Lattice Swelling and Modulus Change in a Helium- Implanted Tungsten Alloy: X-ray Micro-Diffraction, Surface Acoustic Wave Measurements, and Multiscale modelling"

• F. Hofmann
• D. Nguyen-Manh
• C.E. Beck
• J.K.Eliason
• M.R. Gilbert
• A.A. Maznev
• W. Liu
• D.E.J. Armstrong
• K.A. Nelson
• S.L. Dudarev