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Title: Non-coherent Cu grain boundaries driven by continuous vacancy loading

Publication Date:
Research Org.:
Energy Frontier Research Centers (EFRC) (United States). Center for Materials at Irradiation and Mechanical Extremes (CMIME)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
DOE Contract Number:
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Materials Science; Journal Volume: 50; Journal Issue: 11; Related Information: CMIME partners with Los Alamos National Laboratory (lead); Carnegie Mellon University; University of Illinois, Urbana Champaign; Massachusetts Institute of Technology; University of Nebraska
Country of Publication:
United States

Citation Formats

Yu, W. S., and Demkowicz, M. J. Non-coherent Cu grain boundaries driven by continuous vacancy loading. United States: N. p., 2015. Web. doi:10.1007/s10853-015-8961-9.
Yu, W. S., & Demkowicz, M. J. Non-coherent Cu grain boundaries driven by continuous vacancy loading. United States. doi:10.1007/s10853-015-8961-9.
Yu, W. S., and Demkowicz, M. J. 2015. "Non-coherent Cu grain boundaries driven by continuous vacancy loading". United States. doi:10.1007/s10853-015-8961-9.
title = {Non-coherent Cu grain boundaries driven by continuous vacancy loading},
author = {Yu, W. S. and Demkowicz, M. J.},
abstractNote = {},
doi = {10.1007/s10853-015-8961-9},
journal = {Journal of Materials Science},
number = 11,
volume = 50,
place = {United States},
year = 2015,
month = 3
  • The energetics and length scales associated with the interaction between point defects (vacancies and self-interstitial atoms) and grain boundaries in bcc Fe was explored. Molecular statics simulations were used to generate a grain boundary structure database that contained {approx}170 grain boundaries with varying tilt and twist character. Then, vacancy and self-interstitial atom formation energies were calculated at all potential grain boundary sites within 15 {angstrom} of the boundary. The present results provide detailed information about the interaction energies of vacancies and self-interstitial atoms with symmetric tilt grain boundaries in iron and the length scales involved with absorption of these pointmore » defects by grain boundaries. Both low- and high-angle grain boundaries were effective sinks for point defects, with a few low-{Sigma} grain boundaries (e.g., the {Sigma}3{l_brace}112{r_brace} twin boundary) that have properties different from the rest. The formation energies depend on both the local atomic structure and the distance from the boundary center. Additionally, the effect of grain boundary energy, disorientation angle, and {Sigma} designation on the boundary sink strength was explored; the strongest correlation occurred between the grain boundary energy and the mean point defect formation energies. Based on point defect binding energies, interstitials have {approx}80% more grain boundary sites per area and {approx}300% greater site strength than vacancies. Last, the absorption length scale of point defects by grain boundaries is over a full lattice unit larger for interstitials than for vacancies (mean of 6-7 {angstrom} versus 10-11 {angstrom} for vacancies and interstitials, respectively).« less
  • Vacancy loss at a variety of grain boundaries in 99.999 wt.% pure polycrystalline gold quenched from 930/sup 0/C and aged at 60/sup 0/C was studied by transmission electron microscopy. The vacancy precipitate (stacking-fault tetrahedra) free zones, which formed in the regions adjacent to grain boundaries due to vacancy loss at these sinks during quenching, were analyzed. The vacancy sink efficiency of both small-angle and non-special large-angle grain boundaries was found to be high in the presence of the large chemical potential of the quenched-in vacancies. While there is some evidence that the sink efficiency at small angles is somewhat smallermore » than at large angles, the results are not inconsistent with a constant vacancy sink efficiency for all of the small-angle and non-special large-angle boundaries observed. On the other hand, the sink efficiency of the special ..sigma.. = 3 coherent twin boundary is significantly lower than for the non-special boundaries. The results are discussed relative to other work in the field, and it is concluded that both small-angle and non-special large-angle boundaries operate as highly effective sinks at high vacancy chemical potentials; and the sink efficiency tends to fall off as the chemical potential decreases or the boundary becomes more special, i.e., more ordered.« less
  • Atomic resolution {ital Z}-contrast scanning transmission electron microscopy reveals preferential nucleation of electron-beam-induced damage in select atomic columns of a Si tilt grain boundary. Atomic scale simulations find that the region of initial damage nucleation corresponds to columns where the formation energies of vacancies and vacancy complexes are very low. The calculations further predict that vacancy accumulation in certain pairs of columns can induce a structural transformation to low-density dislocation {open_quotes}pipes{close_quotes} with all atoms fourfold coordinated. {copyright} {ital 1999 American Institute of Physics.}
  • he dimer method for searching transition states has been used to systematically study possible migration paths of vacancies, He interstitials and He-vacancy (He/V) clusters at sigma11<110> {323} and sigma3<110> {111} grain boundaries (GBs) in alpha-Fe. Vacancies trapped at the GBs diffuse along the GBs with migration energies much less than that within the perfect crystal. Long-time dynamics simulations of diffusion pathways reveal that vacancies migrate one-dimensionally along specific directions in both GBs: directly along close-packed rows in the sigma3 GB, and in zigzag paths within the sigma11 GB. Also, dimer saddle point searches show that He interstitials can diffuse alongmore » the GBs with migration energies of 0.4-0.5 eV, similar to those of individual vacancies at the GBs, and the corresponding mechanisms are determined. The rate-controlling activation energy for migration of a He-divacancy cluster in the GBs determined using the dimer method is about 0.9 eV. This is comparable to the migration energy for a He-divacancy cluster in bulk alpha-Fe.« less