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Title: Thermal transport at (001) twist grain boundaries in UO 2

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Publication Date:
Research Org.:
Energy Frontier Research Centers (EFRC) (United States). Center for Materials Science of Nuclear Fuel (CMSNF)
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 Nuclear Materials; Journal Volume: 479; Related Information: CMSNF partners with Idaho National Laboratory (lead); Colorado School of Mines; University of Florida; Oak Ridge National Laboratory; Purdue University; University of Wisconsin at Madison
Country of Publication:
United States

Citation Formats

Deng, B., Chernatynskiy, A., Sinnott, S. B., and Phillpot, S. R.. Thermal transport at (001) twist grain boundaries in UO 2. United States: N. p., 2016. Web. doi:10.1016/j.jnucmat.2016.06.054.
Deng, B., Chernatynskiy, A., Sinnott, S. B., & Phillpot, S. R.. Thermal transport at (001) twist grain boundaries in UO 2. United States. doi:10.1016/j.jnucmat.2016.06.054.
Deng, B., Chernatynskiy, A., Sinnott, S. B., and Phillpot, S. R.. 2016. "Thermal transport at (001) twist grain boundaries in UO 2". United States. doi:10.1016/j.jnucmat.2016.06.054.
title = {Thermal transport at (001) twist grain boundaries in UO 2},
author = {Deng, B. and Chernatynskiy, A. and Sinnott, S. B. and Phillpot, S. R.},
abstractNote = {},
doi = {10.1016/j.jnucmat.2016.06.054},
journal = {Journal of Nuclear Materials},
number = ,
volume = 479,
place = {United States},
year = 2016,
month =
  • From a Cu-0.065mass%B solid solution alloy, bicrystals having [001]-twist grain boundaries with various misorientation angles were prepared by the Bridgman method. Cu bicrystals containing B{sub 2}O{sub 3} particles were made from the bicrystals by internal oxidation treatment. The Cu-B{sub 2}O{sub 3} bicrystals were tensile tested at high temperatures, where B{sub 2}O{sub 3} particles become liquid. The amount of grain-boundary sliding was measured from the amount of shear deformation of the liquid B{sub 2}O{sub 3} particles on a sliding grain boundary. Shear deformation of voids where the B{sub 2}O{sub 3} particles was embedded was also utilized to measure the amount ofmore » grain-boundary sliding. The temperature and misorientation-angle dependence of the grain-boundary sliding is discussed for the Cu-B{sub 2}O{sub 3} bicrystals. Since the liquid B{sub 2}O{sub 3} particles easily deform at high temperatures, the measured amount of grain-boundary sliding is considered to reflect the inherent nature of the Cu [001]-twist grain boundaries. Using the present method of measurements, up to 2 {micro}m grain-boundary sliding can be measured with an accuracy of about 0.1 {micro}m.« less
  • Earlier calculations on (100) high-angle twist boundaries in Al are extended to Cu, Ag and Au. Recent pseudopotentials of Dagens together with three empirical potentials for Cu are applied. Boundaries with values of sigma, the inverse density of coincidence sites, ranging between 5 and 73 are considered. In contrast to earlier results for the Al pseudopotential of Dagens et al, the relaxed grain-boundary energy, Esigma, is found to increase smoothly as function of the twist angle, theta, for all six potentials considered here; i.e. ''cusps'' in the Esigma (theta) curve are not observed. Rather, similar boundary structures are obtained formore » the noble-metals; these differ drastically from those derived by means of the pseudopotential for Al. From a comparison with (100) twist boundaries in ionic crystals with NaC1 structure it is concluded that also in the f.c.c. metals a volume expansion at the interface which increases smoothly with theta should be present. Interfacial structures determined without consideration of this expansion are hence concluded to be systematically in error. The article concludes with a summary of the properties of (100) twist boundaries in the f.c.c. and NaC1 structures which are thought to be valid independent of the detailed form of the interatomic potential chosen.« less
  • A new computer code is described which permits the investigation of the energy and structure of coincident-site lattice (CSL) grain boundaries in metals. As an improvement over computer programs used by other workers, the full second-derivative (force-constant) matrix associated with a given interatomic potential is applied for the iterative energy minimization. Using this extremely efficient and reliable procedure the effect of the form of the interatomic potential and its truncation radius on the predicted grain-boundary energy and structure is investigated. Six different potentials for aluminum, ranging from a Morse potential to a pseudopotential, are applied to the simulation of themore » energy and structure (100) CSL twist boundaries with values of ..sigma.., the inverse density of CSL sites, ranging between ..sigma.. = 5 and ..sigma.. = 73. It is found that not only do both the energy and structure of a given boundary vary greatly from one potential to another, but also that the relative energies of different boundaries, i.e. the boundary-energy vs misfit-angle curves, depend on the potential. In contrast to recent claims of Brokman and Balluffi, no cusps in these curves are found for potentials which ignore the charge-density oscillations. The two basic assumptions of the Brokman-Balluffi cusp model are found to be valid only for extremely simple potentials with very short cutoff radii. It is suggested that (1) charge-density oscillations may be important for predicting grain-boundary properties, and (2) no obvious relationship exists between grain-boundary geometry (..sigma..) and the energy. 39 references, 18 figures, 1 table.« less
  • Small gold crystallites ( about50-80 nm dia) were welded to thin film (001) single crystal gol substrates at a series of predetermined (001) twist angles in the range 0.45/sup 0/. A pure (001) twist boundary therefore existed in each welded neck region which could be observed directly by transmission electron microscopy at normal incidence. Upon annealing, the crystallites rotated around (001) when the boundary energy varied with theta. The crystallites rotated into three misorientations corresponding to the special ..sigma..1 and ..sigma..5 misorientations and a symmetry related misorientation at theta = 45/sup 0/. These results indicate the existence of grain boundarymore » dislocation (GBD) related cusps on the boundary energy vs theta curve a ..sigma..1 and ..sigma..5. The rotations occurred conservatively by the motion of screw GBDs which could be observed directly by the transmission microscopy in certain regimes of theta. The results are relevant to recent calculations of the energies of (001) twist boundaries and the applicability of the GBD/structural unit model for grain boundaries.« less