Dislocation Pinning by Small Interstitial Loops: A Molecular Dynamics Study

Molecular dynamics simulations show that, in an embedded atom method nickel crystal, interstitial loops with appropriate geometries, made of four $〈110〉$ dumbbells, are absorbed by the Shockley partials of both static and gliding edge dislocations. Depending on the applied stress, the loops may be either dragged and undergo atomic-level rearrangements or unpin from the dislocation. Such loops induce an additional friction for the dislocation glide which is evaluated from the simulations. Similar effects are also observed when loops with different geometries stabilize a few lattice planes away from the dislocation glide plane.