scholarly journals Continuous description of grain boundaries using crystal defectfields: the example of a {3 1 0}/[0 0 1] tilt boundary in MgO

2017 ◽  
Vol 29 (2) ◽  
pp. 155-165 ◽  
Author(s):  
Xiao-Yu Sun ◽  
Patrick Cordier ◽  
Vincent Taupin ◽  
Claude Fressengeas ◽  
Bijaya B. Karki
Keyword(s):  
Grain Boundaries ◽  
Tilt Boundary ◽  
Continuous Description

Energies and Atomic Structures of Grain Boundaries in Diamond: Comparison With Grain Boundaries in Silicon

1994 ◽  
Vol 339 ◽  
Author(s):  
M. Kohyama ◽  
H. Ichinose ◽  
Y. Ishida ◽  
M. Nakanose
Keyword(s):  
Thin Films ◽  
Grain Boundaries ◽  
Interfacial Energy ◽  
Atomic Structure ◽  
Tight Binding ◽  
Tilt Boundary ◽  
Atomic Structures ◽  
Fundamental Properties ◽  
Diamond Thin Films ◽  
First Time

ABSTRACTFairly different features of grain boundaries in diamond from those in Si were experimentally observed in diamond thin films. As the first step in order to understand the fundamental properties of grain boundaries in diamond, the energy and atomic structure of the {122} σ=9 tilt boundary have been calculated for the first time by using the tight-binding electronic theory. The results have been compared with the calculations of the same boundary and the {111} σ=3 boundary in Si. It has been shown that the σ=9 boundary in diamond has a very large interfacial energy caused by the large bond rigidity as compared with the boundaries in Si and the {111}σ=3 boundary in diamond. This point should be related to the observation that the {122}σ =9 boundary is rarely found in diamond thin films.

Structural multiplicity in a tilt boundary in germanium

1988 ◽  
Vol 46 ◽  
pp. 592-593
Author(s):  
D.A. Smith ◽  
Z. Elgat ◽  
W. Krakow ◽  
A.A. Levi ◽  
C.B. Carter
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Twin Boundary ◽  
Atomic Structure ◽  
Czochralski Method ◽  
Tilt Boundary ◽  
Considerable Progress ◽  
Related Structure ◽  
First Order ◽  
Impurity Segregation

There has been considerable progress made recently in understanding the atomic structure of grain boundaries in metals, semiconductors and ceramics. There is still, however, some dispute over whether a given grain boundary can exist with more than one non-symmetry-related structure. This has been shown experimentally to be the case in Ge for the first-order twin boundary lying parallel to the lateral {112} plane. In the present paper, it will be shown that a similar result holds for a more general grain boundary (actually Σ=137) lying close to the Σ=19 orientation; the Σ=19 boundary is formed by a rotation of 26.5° about a common <110> direction and lies along a common {31} plane. It is thus likely that a similar result will hold for other grain boundaries.Since it is essential to know that the different structures are not due to impurity segregation effects, bicrystals were grown from the melt with pre-oriented seeds using the Czochralski method following the approach of Bacmann as modified at Cornell by Skrotzki et al.

High Resolution Analysis of Structure and Chemistry of Grain Boundaries in Silicon

1991 ◽  
Vol 238 ◽  
Author(s):  
M. J. Kim ◽  
R. W. Carpenter
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Grain Boundaries ◽  
Analytical Electron Microscopy ◽  
Coincident Site Lattice ◽  
Dislocation Core ◽  
Tilt Boundary ◽  
Second Phase ◽  
Twin Boundaries ◽  
Precipitate Morphology

ABSTRACTHigh resolution electron microscopy and high spatial resolution analytical electron microscopy were used to analyze the structure and chemistry of a Σ3 {111} twin boundary in cast polysilicon and a Σ13 (510), [001] tilt boundary in a Si bicrystal. Twin boundaries in cast polysilicon were associated with lattice defects and discrete second phase precipitates. The precipitate was single phase amorphous and faceted on the Si {111} planes. Nanospectroscopy showed mem to be substoichiometric oxide. Similar oxide precipitates, but with different morphology, were also observed on the Σ13 tilt boundary in Si bicrystal, indicating that tilt grain boundaries and steps on twin boundaries were effective heterogeneous sites for nucleation of oxygen containing precipitates. The observed Σ13 tilt boundary exhibited a coincident site lattice periodicity but had an aperiodic interface dislocation core structure. Oxygen that diffused into the boundary in regions where precipitation did not occur may have played a role in modifying the GB core structures, resulting in aperiodicity. For both cases, a detailed analysis of grain boundary atomic structure and precipitate morphology is presented.

Structure of an asymmetrical tilt boundary in gold

1988 ◽  
Vol 46 ◽  
pp. 604-605
Author(s):  
Hans Norden ◽  
David A. Smith
Keyword(s):  
Grain Boundaries ◽  
Periodic Boundary ◽  
Direct Evidence ◽  
Tilt Boundary ◽  
Physical Significance ◽  
Dislocation Model ◽  
Short Period ◽  
Single Crystal Films ◽  
Crystal Films ◽  
Oriented Single Crystal

Balluffi and coworkers developed a technique for making grain boundaries, with chosen misorientations, by welding together appropriately oriented single crystal films. This technique has been used to make gold bicrystals with a misorientation which does not correspond to any short period structure of the kind which is usually thought to have low energy. The procedure followed was to join {100} and {111} single films with <110> directions in each film approximately parallel. With [110](001) and [110](111) exactly parallel an asymmetrical tilt boundary with misorientation 54.73°/[110] is produced. For Σ, the reciprocal fraction of coincidence sites <50, the periodic boundary structures nearest in misorientation are 50.48°/[l10], Σ=11; 55.88°/[110], Σ = 33. Analysis of the present boundaries can therefore give direct evidence relating to the controversial question of the extent of the physical significance of the dislocation model for grain boundaries.Fig. 1 shows a typical region of the interface. Patches of grain boundary are surrounded by regions where the two films are not in contact.

Low-Σ twist and tilt grain boundaries in cubic materials

2011 ◽  
Vol 44 (6) ◽  
pp. 1152-1156 ◽  
Author(s):  
A. Morawiec
Keyword(s):  
Grain Boundaries ◽  
Tilt Boundary ◽  
Polycrystalline Materials ◽  
Two Dimensional ◽  
Special Boundary ◽  
Cubic Symmetry ◽  
Cubic Materials ◽  
Boundary Properties ◽  
Tilt Boundaries ◽  
Twist Boundaries

Knowledge of the geometry of grain boundaries in polycrystalline materials is essential for predicting boundary properties. The issue of cataloging the geometrically characterized groups of twist and tilt boundaries is addressed. All distinct types of pure-twist and pure-tilt boundaries are determined for misorientations corresponding to highly coincident (3 ≤ Σ ≤ 13) lattices of cubic symmetry. For these particular misorientations, the number of distinct twist boundaries and zones of tilt boundaries ranges from 5 (Σ = 3) to 11 (Σ = 9 or 11). Maps displaying the locations of twist and tilt boundary planes indicate boundaries having particular geometries with two-dimensional periodicities. This is of significance for identification of special boundary structures. Moreover, the maps allow for relating peaks on experimentally determined grain boundary distributions to particular types of twist or tilt boundaries.

The Structure of Grain Boundaries and Phase Boundaries in Ceramics

1983 ◽  
Vol 31 ◽  
Author(s):  
C. B. Carter
Keyword(s):  
Grain Boundaries ◽  
Twin Boundary ◽  
Tilt Boundary ◽  
Twist Boundary ◽  
Phase Boundaries ◽  
Large Unit ◽  
First Order ◽  
Unit Cells ◽  
Ionic Nature

ABSTRACTThe structure of different grain boundaries and phase boundaries are discussed by reference to a series of specific examples. The chosen examples of grain boundaries include the <l10>{l10} tilt boundary, the (001) twist boundary and the first-order twin boundary in spinel and the basal twin and the (1123) twin in Al2O3 . The phase boundaries discussed are the β'''-alumina/spinel interface, the wustite/spinel interface and the spinel/alumina interface. It is shown that these interfaces do have properties which result specifically from the ionic nature of the material and the large unit cells involved in each case.

Excess Free Volume of High Angle Grain Boundaries in Aluminium

2006 ◽  
Vol 519-521 ◽  
pp. 1557-1562 ◽  
Author(s):  
V.A. Ivanov ◽  
Dmitri A. Molodov ◽  
Lasar S. Shvindlerman ◽  
Günter Gottstein ◽  
D. Kolesnikov ◽  
...  
Keyword(s):  
Grain Boundaries ◽  
Free Volume ◽  
Pressure Range ◽  
Boundary Energy ◽  
Tilt Boundary ◽  
Triple Junctions ◽  
High Angle ◽  
Absolute Value ◽  
Excess Free Volume ◽  
Tilt Boundaries

A new method is introduced to determine the absolute value of the boundary excess free volume. Along with the boundary energy the excess free volume belongs to the major thermodynamic properties of grain boundaries. The method utilizes the dependence of the contact angle at triple junctions of grain boundaries in Al-tricrystals on hydrostatic pressure. We investigated <111> tilt boundaries in the pressure range up to 14 kbar. In particular, for a 40° <111> tilt boundary with 2° twist component the boundary free volume was found to be equal to 5.03×10-11 m3/m2.

Structure imaging of grain boundaries in F.C.C. metals

1990 ◽  
Vol 48 (4) ◽  
pp. 334-335
Author(s):  
William Krakow
Keyword(s):  
Grain Boundaries ◽  
Computer Modelling ◽  
Image Interpretation ◽  
Tilt Boundary ◽  
Open Structures ◽  
Microscopic Studies ◽  
Resolution Level ◽  
Symmetrical Tilt ◽  
Au Thin Films ◽  
Lattice Planes

One can now extract information about the projected atomic structure of tilt grain boundaries in metals from zone axes orientations which are not the most open structures as in previous lower voltage microscopic studies of a few years ago. This has been made possible in part by the development of intermediate voltage microscopes capable of a point resolution exceeding 2Å level For these studies it was also necessary to develop techniques for fabricating tilt boundary structures from epitaxially grown Au thin films placed in contact. Analysis of grain boundary micrographs further required that Fourier image filtering and enhancement be applied to the original micrographs. Subsequent computer modelling of the dynamical diffraction processes and images was also necessary to insure the proper image interpretation.An example of a ∼80Å thick thin film containing a symmetrical tilt boundary corresponding to a Σ = 17/[001]28.1° (410) is displayed in Fig. 1. There is a [100] tilt axis common to both grains and the {200} crossed sets lattice planes on each side of the interface require a resolution level of 2.03Å which is well beyond the {111} planar spacings of 2.3Å of the most open [110] orientation in Au. Here the atom columns are designated by either open circles or crosses corresponding to a two layer repeat. The boundary dislocation cores are designated by structural units of capped trigonal prisms or the same with one cap modifying to contain a rhombohedron unit.

Impact of Boundary Orientation on the Motion of Curved Grain Boundaries in Aluminum Bicrystals

2004 ◽  
Vol 467-470 ◽  
pp. 751-756 ◽  
Author(s):  
V.A. Ivanov ◽  
Dmitri A. Molodov ◽  
Lasar S. Shvindlerman ◽  
Günter Gottstein
Keyword(s):  
Steady State ◽  
Grain Boundaries ◽  
Misorientation Angle ◽  
Mixed Boundary ◽  
Tilt Boundary ◽  
Twist Boundary ◽  
Geometrical Configuration ◽  
Boundary Orientation ◽  
Tilt Boundaries ◽  
Misorientation Angles

The motion of <111> tilt and mixed tilt-twist grain boundaries with misorientation angles in the range between 34° and 42° in pure Al bicrystals was measured over the temperature range between 310 and 610°C. The experiments revealed that the change of the set of boundary planes in the curved moving tilt boundary does not affect its motion. The shape of the curved moving part of the mixed tilt-twist boundary was measured and compared with analytically calculated boundary shape. The results have shown that an increase of the twist component along the curved mixed boundary in studied geometrical configuration does not affect its steady-state motion. Similar to the behaviour of <111> pure tilt boundaries, the mobility of <111> mixed tilt-twist grain boundaries in the vicinity of special misorientation å7 depends on the misorientation angle in a non-monotonic fashion.

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