The Recombination of Tungsten Intrinsic Defects near the Surface Blocked by Hydrogen and Helium Atoms

Stable configurations of point radiation defects of tungsten near the surface were investigated within the density functional theory. The emergence of an self-interstitial atom leads to formation of a crowdion. The transformation of this configuration into a configuration with an adsorbed W atom is a thermally activated process with the energy barrier of 1.38 eV. When a single vacancy emerges near the crowdion close to the surface, a recombination occurs. Impurity atoms in the vacancy near the surface are capable of blocking the recombination process, acting as a factor that increases the radiation damage of tungsten.