Light ion irradiation produces vacancies and interstitials that may migrate to grain boundaries (GBs), generally in unequal amounts. We use atomistic modeling to study the response of mixed tilt/twist Σ9 and Σ11 GBs and an asymmetric Σ3 GB in copper (Cu) to continuous vacancy fluxes. We find that GB ground states cannot be reached through annealing alone, but require removal of excess atoms from the GBs. GB energies vary periodically as function of number of vacancies created. Although GB ground states recur, they may exhibit distinct GB structures, some of which are faceted. We describe how GB properties, such as vacancy formation energies and volumes, depend on the number of vacancies created in the GB. Furthermore, we find that continuous vacancy fluxes to GBs drive GB migration and shearing.
This material is based upon work supported as part of the Center for Materials at Irradiation and Mechanical Extremes, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award Number 2008LANL1026.
Massachusetts of Institute of Technology
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