The effect of excess atomic volume on He bubble formation at fcc-bcc interfaces

Abstract

Atomistic modeling shows that Cu–Nb and Cu–V interfaces contain high excess atomic volume due to constitutional vacancy concentrations of ∼ 5 at. % and ∼ 0.8 at. %., respectively. This finding is supported by experiments demonstrating that an approximately fivefold higher He concentration is required to observe He bubbles via through-focus transmission electron microscopy at Cu–Nb interfaces than in Cu–V interfaces. Interfaces with structures tailored to minimize precipitation and growth of He bubbles may be used to design damage-resistant composites for fusion reactors.