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…
Preprint PurchaseDaniel 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…
Preprint PurchaseSuchandrima 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 PublishedJan Fikar Robin Schaeublin Daniel R. Mason Duc Nguyen-Manh
The vacancies produced in high energy collision cascades of irradiated tungsten can form vacancy clusters or prismatic vacancy dislocation loops. Moreover, vacancy loops can easily transform into planar vacancy clusters. We investigated the formation energies of these three types of vacancy defects as a function of the number of vacancies using thr…
PublishedDaniel R. Mason Andrew J. London
We present a morphological analysis of atom probe data of nanoscale microstructural features, using methods developed by the astrophysics community to describe the shape of superclusters of galaxies. We describe second-phase regions using Minkowski functionals, representing the regions’ volume, surface area, mean curvature and Euler characteristi…
Preprint PublishedDaniel 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 PublishedDaniel 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