Mobility of nano-sized 1⁄2⟨1 1 1⟩ vacancy and interstitial prismatic dislocation loops in tungsten
The vacancies and interstitials produced in high-energy collision cascades of irradiated tungsten can form prismatic dislocation loops with Burgers vectors 1⁄2⟨1 1 1⟩ and ⟨1 0 0⟩. The 1⁄2⟨1 1 1⟩ loops are very mobile, and their mobility is essential for the microstructure development of irradiated materials, It is a key parameter for predictive models such as kinetic Monte Carlo. We investigated the mobility of 1⁄2⟨1 1 1⟩ vacancy and interstitial hexagonal loops as a function of their size using the recent embedded-atom method tungsten potential. The phonon drag phenomenon occurs at high temperatures and can be separated during post-processing from the thermally activated motion. The magnitude of the phonon drag at 300K was evaluated and appeared to be critical for single interstitial atoms, with a nearly ten-fold increase of their diffusion, while dislocation loops are less influenced.