Incoherent Twin Boundary Migration Induced By Ion Irradiation In Cu

Grain boundaries can act as sinks for radiation-induced point defects. The sink capability is dependent on the atomic structures and varies with the type of point defects. Using high-resolution transmission electron microscopy, we observed that Sigma 3{112} incoherent twin boundary (ITB) in Cu films migrates under Cu3+ ion irradiation. Using atomistic modeling, we found that Sigma 3{112} ITB has the preferred sites for adsorbing interstitials and the preferential diffusion channels along the Shockley partial dislocations. Coupling with the high mobility of grain boundary Shockley dislocations within Sigma 3{112} ITB, we infer that Sigma 3{112} ITB migrates through the collective glide of grain boundary Shockley dislocations, driven by a concurrent reduction in the density of radiation-induced defects, which is demonstrated by the distribution of nearby radiation-induced defects. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4774242]