Periodic grain boundary structures in aluminium. II. A geometrical method for analysing periodic grain boundary structure and some related transmission electron microscope observations

A crystallographic treatment is developed which clarifies the relation between the structure of a grain boundary and its location between relatively translated crystals. Characterization of line defects which can exist in grain boundaries is also facilitated by using this treatment, and the following topics are considered: (1) the computed structures in part I of this work; (2) steps at the cores of perfect grain boundary dislocations; (3) boundary structures related by c.s.l. symmetry; (4) partial grain boundary dislocations. Transmission electron microscope observations of topic 4 are presented.

Download Full-text

Observations and implications of grain boundary dislocation networks in high-angle YBa2Cu3O7−δ grain boundaries

Journal of Materials Research ◽

10.1557/jmr.1990.0919 ◽

1990 ◽

Vol 5 (5) ◽

pp. 919-928 ◽

Cited By ~ 66

Author(s):

S. E. Babcock ◽

D. C. Larbalestier

Keyword(s):

Grain Boundary ◽

Grain Boundaries ◽

Weak Link ◽

Coincidence Site Lattice ◽

Boundary Structure ◽

High Angle ◽

Grain Boundary Structure ◽

Transmission Electron ◽

Means Of Transmission ◽

Regular Networks

Regular networks of localized grain boundary dislocations (GBDs) have been imaged by means of transmission electron microscopy in three different types of high-angle grain boundaries in YBa2Cu3O7-δ, implying that these boundaries possess ordered structures upon which a significant periodic strain field is superimposed. The occurrence of these GBD networks is shown to be consistent with the GBD/Structural Unit and Coincidence Site Lattice (CSL)/Near CSL descriptions for grain boundary structure. Thus, these dislocations appear to be intrinsic features of the boundary structure. The spacing of the observed GBDs ranged from ∼10 nm to ∼100 nm. These GBDs make the grain boundaries heterogeneous on a scale that approaches the coherence length and may contribute to their weak-link character by producing the “superconducting micro-bridge” microstructure which has been suggested on the basis of detailed electromagnetic measurements on similar samples.

Download Full-text

Grain Boundary Responses to Local and Applied Stress: An In Situ TEM Deformation Study

MRS Proceedings ◽

10.1557/proc-976-0976-ee02-01 ◽

2006 ◽

Vol 976 ◽

Author(s):

Bryan Miller ◽

Jamey Fenske ◽

Dong Su ◽

Chung-Ming Li ◽

Lisa Dougherty ◽

...

Keyword(s):

Electron Microscope ◽

Grain Boundary ◽

Grain Boundaries ◽

Grain Growth ◽

Transmission Electron Microscope ◽

In Situ Tem ◽

Deformation Twins ◽

Transmission Electron ◽

Dislocation Interactions

AbstractDeformation experiments at temperatures between 300 and 750 K have been performed in situ in the transmission electron microscope to investigate dislocation interactions and reactions with grain boundaries and other obstacles. Dislocations, both partial and perfect, as well as deformation twins have been observed being emitted from grain boundaries and, in some cases, even the same grain boundary. The ejection of dislocations from the grain boundary can result in its partial or total annihilation. In the latter case, the disintegration of the grain boundary was accompanied by grain growth and a change in misorientation.

Download Full-text

Grain Boundary Characterization of Nanocrystalline Cu from the Stereological Analysis of Transmission Electron Microscope Orientation Maps

Microscopy and Microanalysis ◽

10.1017/s1431927611007951 ◽

2011 ◽

Vol 17 (S2) ◽

pp. 1416-1417 ◽

Cited By ~ 1

Author(s):

A Darbal ◽

K Ganesh ◽

K Barmak ◽

G Rohrer ◽

P Ferreira ◽

...

Keyword(s):

Electron Microscope ◽

Grain Boundary ◽

Transmission Electron Microscope ◽

Stereological Analysis ◽

Transmission Electron ◽

Orientation Maps

Extended abstract of a paper presented at Microscopy and Microanalysis 2011 in Nashville, Tennessee, USA, August 7–August 11, 2011.

Download Full-text

Grain Boundary Characterization of Nanocrystalline Cu from the Stereological Analysis of Transmission Electron Microscope Orientation Maps

Microscopy and Microanalysis ◽

10.1017/s1431927611008002 ◽

2011 ◽

Vol 17 (S2) ◽

pp. 1426-1427

Author(s):

A Darbal ◽

K Ganesh ◽

K Barmak ◽

G Rohrer ◽

P Ferreira ◽

...

Keyword(s):

Electron Microscope ◽

Grain Boundary ◽

Transmission Electron Microscope ◽

Stereological Analysis ◽

Transmission Electron ◽

Orientation Maps

Extended abstract of a paper presented at Microscopy and Microanalysis 2011 in Nashville, Tennessee, USA, August 7–August 11, 2011.

Download Full-text

First-Principles Studies on Grain Boundary Energies of [110] Tilt Grain Boundaries in Aluminum

Materials Science Forum ◽

10.4028/www.scientific.net/msf.561-565.1837 ◽

2007 ◽

Vol 561-565 ◽

pp. 1837-1840 ◽

Cited By ~ 9

Author(s):

Y. Inoue ◽

Tokuteru Uesugi ◽

Yorinobu Takigawa ◽

Kenji Higashi

Keyword(s):

Grain Boundary ◽

Grain Boundaries ◽

Atomic Structure ◽

First Principles ◽

Boundary Structure ◽

First Principles Calculations ◽

Atomic Structures ◽

Grain Boundary Structure ◽

Transmission Electron ◽

Tilt Grain Boundary

The grain boundary structure and its energy are necessary for the fundamental understanding of the physical properties of materials. In aluminum, three distinct atomic structures of a Σ9(221)[110] tilt grain boundary have been reported in previous studies using atomistic simulations and a high-resolution transmission electron microscopy (HRTEM). In this work, we studied the atomic structure and energy of the Σ9 tilt grain boundary in aluminum using first-principles calculations. A comparison of the grain boundary energies among the three distinct Σ9 tilt grain boundaries determined through first-principles calculations allowed us to identify the most stable atomic structure of Σ9 tilt grain boundary in aluminum.

Download Full-text

Quantitative Analysis of Interface Structure by HRTEM

Microscopy and Microanalysis ◽

10.1017/s1431927600027276 ◽

2001 ◽

Vol 7 (S2) ◽

pp. 240-241

Author(s):

Frank Ernst

Keyword(s):

Grain Boundary ◽

Grain Boundaries ◽

Point Defects ◽

Experimental Studies ◽

Boundary Structure ◽

Atomistic Modeling ◽

Active Point ◽

Grain Boundary Structure ◽

Transmission Electron ◽

Atomistic Structure

The development of ‘quantitative’ high-resolution transmission electron microscopy (QHRTEM) has led to considerable progress in analyzing and understanding the atomistic structure of grain boundaries and heterointerfaces, which often control relevant macroscopic properties of materials. The following results of recent experimental studies and the comparison of these results with atomistic modeling demonstrate the strength of QHRTEM:1.Grain Boundaries in SrTiO3. Some technical applications of SrTiO3 ceramics rely on special electric properties of this material, which originate from segregation of electrically active point defects to grain boundaries. QHRTEM can substantially contribute to understanding the correlation between the atomistic structure of grain boundaries and the segregation of point defects to these interfaces. As an example for a grain boundary structure solved by QHRTEM, FIGs. la and b present an experimental HRTEM image of the Σ= 3, (111) grain boundary in SrTiO3 and the corresponding atomistic structure as obtained by QHRTEM.

Download Full-text

Grain Boundary Structure in ARB Processed Copper

Materials Science Forum ◽

10.4028/www.scientific.net/msf.503-504.925 ◽

2006 ◽

Vol 503-504 ◽

pp. 925-930 ◽

Cited By ~ 1

Author(s):

Kenichi Ikeda ◽

Naoki Takata ◽

Kousuke Yamada ◽

Fuyuki Yoshida ◽

Hideharu Nakashima ◽

...

Keyword(s):

Grain Boundary ◽

Grain Boundaries ◽

Structural Unit ◽

Md Simulation ◽

Boundary Structure ◽

Dislocation Model ◽

Grain Boundary Structure ◽

Transmission Electron ◽

Symmetric Tilt ◽

The Difference

Grain boundary structures in the Accumulative roll-bonding (ARB) processed copper (ARB-Cu) have been studied. The grain boundary structures were observed by high-resolution transmission electron microscopy (HRTEM). In order to clarify the difference between the grain boundaries in ARB-Cu and equilibrium boundaries, calculated atomic structure of symmetric tilt grain boundaries with <110> common axis (<110> symmetric tilt grain boundary; <110> STGB) in Cu were used. The near 14° boundary in the ARB-Cu could be described by the dislocation model, but the dense dislocation region existed near the grain boundary. The high angle boundaries in ARB-Cu could be described by the structural units which were obtained by molecular dynamics (MD) simulation. Furthermore, in the 2 cycles and 6 cycles ARB-Cu (2cARB-Cu and 6cARB-Cu), the deformation twin boundaries could be observed and described by the structural unit. Therefore, it was concluded that the grain boundary structure in the ARB-Cu was not much different from the normal equilibrium grain boundary and explained by conventional dislocation and structural unit models.

Download Full-text