English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

In this work, we combine Density Functional Theory data with a Thermodynamicand a kinetic model to determine the total concentration of hydrogen implantedin the sub-surface of tungsten exposed to a hydrogen flux. The sub-surfacehydrogen concentration is calculated given a flux of hydrogen, a temperature ofimplantation, and the energy of the incoming hydrogen ions as independentvariables. This global model is built step by step; an equilibrium betweenatomic hydrogen within bulk tungsten and a molecular hydrogen gas phase isfirst considered, and the calculated solubility is compared with experimentalresults. Subsequently, a kinetic model is used to determine the chemicalpotential for hydrogen in the sub-surface of tungsten. Combining both thesemodels, two regimes are established in which hydrogen is preferentially trappedat either interstitial sites or in vacancies. We deduce from our model that theexistence of these two regimes is driven by the temperature of the implantedtungsten sample; above a threshold or transition temperature is theinterstitial regime, below is the vacancy regime in which super-saturatedlayers form within tenths of angstrom below the surface. A simple analyticalexpression is derived for the coexistence of the two regimes depending on theimplantation temperature, the incident energy and the flux of the hydrogen ionswhich we use to plot the corresponding phase diagram.

Hydrogen supersaturated layers in H/D plasma-loaded tungsten: A global model based on thermodynamics, kinetics and density functional theory data