Atomistic insight into the unique mechanism of helium management at FCC {111}//{111}FCC semi-coherent interfaces

Interfaces are effective traps for implanted helium (He), and research on the He interactions with interfaces contributes to our comprehension of the role of interface structure in controlling and mitigating the deleterious effects of He. In this study, we investigate He interactions with three types of face-centered cubic (FCC){111}// {111}FCC semi-coherent interfaces: Cu/Ni, Cu/Pd, and Cu/Ag {111} semi-coherent interfaces. Utilizing molecular dynamics simulations, we demonstrate that He atoms exhibit a tendency to segregate at these semicoherent interfaces. Notably, the presence of new dislocation loops, accompanied by extrinsic stacking faults, is observed at these semi-coherent interfaces as the concentration of He atoms increases continuously. Moreover, this unique structural evolution of interfaces leads to the dissociation of misfit dislocation intersections, thereby significantly augmenting the nucleation sites for He atoms and improving the He managements at these interfaces. These findings provide insights into the interaction between He atoms and FCC{111}//{111}FCC semicoherent interfaces, enriching our current understanding of He management at such interfaces.