A unified theory of grain boundaries. I. Symmetrie tilt boundaries

1973 ◽  
Vol 17 (2) ◽  
pp. 423-433 ◽  
Author(s):  
M. J. Marcinkowski ◽  
K. Sadananda ◽  
Wen Feng Tseng
Keyword(s):  
Grain Boundaries ◽  
Unified Theory ◽  
Tilt Boundaries

A Unified Theory of Grain Boundaries I. Symmetric Tilt Boundaries

1973 ◽  
pp. 423-435
Author(s):  
M. J. Marcinkowski ◽  
K. Sadananda ◽  
Wen Feng Tseng
Keyword(s):  
Grain Boundaries ◽  
Unified Theory ◽  
Symmetric Tilt ◽  
Tilt Boundaries

A unified theory of grain boundaries. II. Asymmetric tilt boundaries

1973 ◽  
Vol 18 (1) ◽  
pp. 361-375 ◽  
Author(s):  
M. J. Marcinkowski ◽  
K. Sadananda
Keyword(s):  
Grain Boundaries ◽  
Unified Theory ◽  
Tilt Boundaries

High-resolution x-ray analysis of dislocation networks nn tilt boundaries

1988 ◽  
Vol 46 ◽  
pp. 612-613
Author(s):  
J. R. Michael ◽  
C. H. Lin ◽  
S. L. Sass
Keyword(s):  
Grain Boundaries ◽  
Analytical Electron Microscopy ◽  
Solute Segregation ◽  
X Ray ◽  
Periodic Arrays ◽  
Analytical Electron ◽  
Primary Dislocation ◽  
Tilt Boundaries ◽  
Polycrystalline Solids ◽  
Twist Boundaries

The segregation of solute atoms to grain boundaries in polycrystalline solids can be responsible for embrittlement of the grain boundaries. Although Auger electron spectroscopy (AES) and analytical electron microscopy (AEM) have verified the occurrence of solute segregation to grain boundaries, there has been little experimental evidence concerning the distribution of the solute within the plane of the interface. Sickafus and Sass showed that Au segregation causes a change in the primary dislocation structure of small angle [001] twist boundaries in Fe. The bicrystal specimens used in their work, which contain periodic arrays of dislocations to which Au is segregated, provide an excellent opportunity to study the distribution of Au within the boundary by AEM.The thin film Fe-0.8 at% Au bicrystals (composition determined by Rutherford backscattering spectroscopy), ∼60 nm thick, containing [001] twist boundaries were prepared as described previously. The bicrystals were analyzed in a Vacuum Generators HB-501 AEM with a field emission electron source and a Link Analytical windowless x-ray detector.

Atomic Structure and Property Correlation in Pulsed Laser Deposited High -Tc Films

1998 ◽  
Vol 526 ◽  
Author(s):  
R. Kalyanaraman ◽  
S. Oktyabrsky ◽  
K. Jagannadham ◽  
J. Narayan
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Grain Boundaries ◽  
Atomic Structure ◽  
Substrate Surface ◽  
Pulsed Laser ◽  
Structure And Property ◽  
Transmission Electron ◽  
Tilt Boundaries ◽  
Z Contrast

AbstractThe atomic structure of grain boundaries in pulsed laser deposited YBCO/MgO thin films have been studied using transmission electron microscopy. The films have perfect texturing with YBCO(001)//MgO(001), giving rise to low-angle [001] tilt boundaries from the grains with the c-axis normal to substrate surface. Low angle grain boundaries have been found to be aligned preferentially along (100) and (110) interface planes. The energy of (110) boundary planes described by an alternating array of [100] and [010] dislocation is found to be comparable to the energy of a (100) boundary. The existence of these split dislocations is shown to further reduce the theoretical current densities of these boundaries indicating that (110) boundaries carry less current as compared to (100) boundaries of the same misorientation angle. Further, Z-contrast transmission electron microscopy of a 42° asymmetric high-angle grain boundary of YBCO shows evidence for the existence of boundary fragments and a reduced atomic density along the boundary plane

Interaction Between Lattice Dislocations and Grain Boundaries In Ordered Compounds

1990 ◽  
Vol 213 ◽  
Author(s):  
B.J. Pestman ◽  
J. Th. M. De Hosson ◽  
V. Vitek ◽  
F.W. Schapink
Keyword(s):  
Shear Stress ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Partial Dislocation ◽  
Atomistic Simulations ◽  
Many Body ◽  
Shockley Partial Dislocation ◽  
Screw Dislocations ◽  
Applied Shear Stress ◽  
Tilt Boundaries

ABSTRACTThe interaction of 1/2<1 1 0> screw dislocations with symmetric [1 1 0] tilt boundaries was investigated by atomistic simulations using many-body potentials representing ordered compounds. The calculations were performed with and without an applied shear stress. The observations were: absorption into the grain boundary, attraction of a lattice Shockley partial dislocation towards the grain boundary and transmission through the grain boundary under the influence of a shear stress. It was found that the interaction in ordered compounds shows similarities to the interaction in fcc.

Unified Theory of Grain Boundaries. An Update

1982 ◽  
Vol 73 (2) ◽  
pp. 409-419 ◽  
Author(s):  
M. J. Marcinkowski
Keyword(s):  
Grain Boundaries ◽  
Unified Theory

Frequencies of Tilt and Twist Boundaries among Random Grain Boundaries

2010 ◽  
Vol 160 ◽  
pp. 95-99 ◽  
Author(s):  
Adam Morawiec
Keyword(s):  
Computer Program ◽  
Grain Boundaries ◽  
Random Boundary ◽  
Small Deviations ◽  
Tilt Boundaries ◽  
The Difference ◽  
Twist Boundaries

There are a number of classifications of homophase grain boundaries. It is quite common to divide them into twist, tilt and general boundaries. As in the case of the classification into coincident lattice (CSL) boundaries and non-CSL boundaries, one may ask about the possible frequencies of incidence of tilt and twist boundaries in a set of “random” boundaries. The proba¬bilities of occurrence of these particular boundary types are clearly defined if small deviations from pure twist and tilt conditions are allowed. We estimated the probabilities numerically for the cases of cubic and hexagonal holohedries. For a given randomly generated boundary, a computer program searched for the nearest pure-tilt and pure-twist boundaries. All symmetrically equivalent representations of the random boundary were processed, and the smallest distance was taken as the result. The distance was based on both the difference in misorientations and the deviation between boundary inclinations. The findings concerning tilt boundaries turned out to be striking. For instance, if the allowed deviation from pure-tilt conditions is only 1°, then as many as 39.0% and 21.2% of random boundaries have near-tilt character for the cubic and hexagonal cases, respectively. If the limiting deviation is raised to 5°, the frequencies of near-tilt boundaries reach 98.6% and 77.0%, respectively.

The Structure of Dislocations in Low-Angle Grain Boundaries in the Diamond Cubic Lattice

1981 ◽  
Vol 5 ◽  
Author(s):  
C.B. Carter
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Stacking Faults ◽  
Burgers Vector ◽  
Cubic Lattice ◽  
Partial Dislocations ◽  
Tilt Boundaries ◽  
P Type ◽  
Twist Boundaries

ABSTRACTDislocations in low-angle tilt boundaries exhibit a wide variety of Burgers vector including a/2<112> a<001> and a<111>. The dislocations are usually dissociated: Shohkley, stair-rod and Frank partial dislocations may each be formed together with associated intrinsic and extrinsic stackingfaults. Dislocations in low-angle {111} twist boundaries are usually assumed to dissociated by a glide mechanism to give two types of extended nodes, known as P–type and K–type, which contain intrinsic and extrinsic stacking-faults respectively. It is shown that dissociation by climb actually occurs for both types of grain boundary.

Characterization of Grain Boundaries and Interfaces by High Resolution Transmission Electron Microscopy

1989 ◽  
Vol 153 ◽  
Author(s):  
William Krakow
Keyword(s):  
High Resolution ◽  
Grain Boundaries ◽  
Ohmic Contacts ◽  
Dielectric Material ◽  
Medium Voltage ◽  
Voltage Electron ◽  
Resolution Electron ◽  
Interfacial Structures ◽  
Tilt Boundaries ◽  
Electron Microscopes

AbstractSeveral examples will be given of high resolution electron microscope images of both grain boundaries and interfaces and the methods which have been applied to understanding their atomic structure. Specific expitaxial interfacial structures considered are: Pd2Si/Si used for ohmic contacts, Al on Si overlayers and CaF2/Si where the CaF2, is an attractive possibility as a dielectric material. For the case of grain boundaries specific examples of both twist and tilt boundaries in Au will be given to show the imaging capability with the new generation of medium voltage electron microscopes.

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