Interstitial clusters on Σ = 11(113) grain boundary in copper: Geometric structure, stability, and ability to annihilate vacancies

• The interstitials on GB plane energetically prefer to accumulate into a cluster.
• Interstitial clusters tend to present in a linear structure along direction [11¯0].
• Interstitial clusters will be more stable with the increase of their lengths.
• The ability of interstitials healing vacancies is reduced when clusters formed.
• Interstitials in clusters still can be efficiently emitted to annihilate vacancies.

The properties of interstitial clusters on Σ=11(113)Σ=11(113) grain boundary (GB) in copper are studied by first-principle calculations. The results show that the interstitial atoms on GB plane energetically tend to accumulate into a cluster. The geometric structures of interstitial clusters prefer to present in a line along the direction [11¯0] on Σ=11 GBΣ=11 GB plane if the grain boundary and neighbor lattices remain undamaged, and the stability of clusters increases with their elongation. The ability of interstitials in clusters to annihilate vacancies is decreased compared with isolated interstitials, however, interstitial clusters still could efficiently heal vacancies within a certain distance from grain boundary.