Electronically Temperature-Dependent Interplay between He and Trivacancy in Tungsten Plasma-Facing Materials.

Area of Science:

• Materials Science
• Nuclear Engineering
• Computational Physics

Background:

• Tungsten (W) is crucial for plasma-facing materials (PFMs) in fusion reactors.
• Microvoids and helium (He) impurities are common defects in W-PFMs.
• He-microvoid interactions influence material performance and longevity.

Purpose of the Study:

• Investigate the interaction between He atoms and trivacancy (V3) defects in W.
• Elucidate the mechanisms of He-induced microvoid evolution.
• Understand the role of electronic excitation in these processes.

Main Methods:

• Tight-binding theory simulations.
• Analysis of d-electron charge distribution.
• Modeling of electrostatic interactions.

Main Results:

• He atoms catalyze V3 decomposition and transformation.
• He induces charge redistribution in surrounding W atoms, creating cationic and anionic sites.
• Electronic excitation intensifies W atom ionization, altering interatomic interactions and potentially inhibiting V3 deformation.

Conclusions:

• He-V3 interactions are complex, involving charge redistribution and defect transformation.
• Electronic excitation plays a critical role in modulating He-V3 interactions.
• Understanding these mechanisms is vital for designing robust W-PFMs.