International audienceDeveloping predictive models for the microstructure evolution of materials requires an accurate description of the point defects fluxes to the different sinks, such as dislocations, grain boundaries and cavities. This work aims at improving the evaluation of sink strengths of dislocations and cavities using object kinetic Monte-Carlo simulations parametrized with density functional theory calculations. The present accurate description of point defects migration enables quantitative assessment of the influence of the point defects anisotropy at saddle point. The results in aluminum show that the anisotropy at saddle point has a large influence on sink strengths. In particular, this anisotropy leads to the cavity being a biased sink. These results are explained by the analysis of the point defect trajectories to the sinks, which are shown to be strongly affected by the saddle point anisotropy

Modification of materials using ion beams has become a widespread route to improve or design materials for advanced applications, from ion doping for microelectronic devices to emulation of nuclear reactor environments. Yet, despite decades of studies, major issues regarding ion/solid interactions are not solved, one of them being the lattice-strain development process in irradiated crystals. In this work, we address this question using a consistent approach that combines X-ray diffraction (XRD) measurements with both molecular dynamics (MD) and rate equation cluster dynamics (RECD) simulations. We investigate four distinct materials that differ notably in terms of crystalline structure and nature of the atomic bonding. We demonstrate that these materials exhibit a common behaviour with respect to the strain development process. In fact, a strain build-up followed by a strain relaxation is observed in the four investigated cases. The strain variation is unambiguously ascribed to a change in the defect configuration, as revealed by MD simulations. Strain development is due to the clustering of interstitial defects into dislocation loops, while the strain release is associated with the disappearance of these loops through their integration into a network of dislocation lines. RECD calculations of strain depth profiles, which are in agreement with experimental data, indicate that the driving force for the change in the defect nature is the defect clustering process. This study paves the way for quantitative predictions of the microstructure changes in irradiated materials.