Near Atomic Scale Nanochemistry and Structure: Ceramic Grain Boundaries and Interfaces

1998 ◽  
pp. 95-106
Author(s):  
R. W. Carpenter ◽  
W. Braue
Keyword(s):  
Grain Boundaries ◽  
Atomic Scale

scholarly journals Atomic Scale Investigation of Orthopyroxene and Olivine Grain Boundaries by Atom Probe Tomography

2015 ◽  
Vol 21 (S3) ◽  
pp. 1315-1316 ◽  
Author(s):  
Mukesh Bachhav ◽  
Yan Dong ◽  
Philip Skemer ◽  
Emmanuelle A. Marquis
Keyword(s):  
Grain Boundaries ◽  
Atom Probe Tomography ◽  
Atom Probe ◽  
Atomic Scale

Atomic Scale Analysis of a YSZ Bicrystal Grain Boundary

2001 ◽  
Vol 7 (S2) ◽  
pp. 400-401
Author(s):  
Y. Lei ◽  
Y. Ito ◽  
N. D. Browning
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Bulk Material ◽  
Atomic Scale ◽  
Structure Property ◽  
Contrast Imaging ◽  
Structure Property Relationships ◽  
Commercial Applications ◽  
Z Contrast ◽  
Electron Energy Loss

Yttria-stabilized zirconia (YSZ) has been the subject of many experimental and theoretical studies, due to the commercial applications of zirconia-based ceramics in solid state oxide fuel cells. Since the grain boundaries usually dominate the overall macroscopic performance of the bulk material, it is essential to develop a fundamental understanding of their structure-property relationships. Previous research has been performed on the atomic structure of grain boundaries in YSZ, but no precise atomic scale compositional and chemistry characterization has been carried out. Here we report a detailed analytical study of an [001] symmetric 24° bicrystal tilt grain boundary in YSZ prepared with ∼10 mol % Y2O3 by Shinkosha Co., Ltd by the combination of Z-contrast imaging and electron energy loss spectroscopy (EELS).The experimental analysis of the YSZ sample was carried out on a 200kV Schottky field emission JEOL 201 OF STEM/TEM4.

scholarly journals Segregation of P and S Impurities to A Σ9 Grain Boundary in Cu

Metals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1362
Author(s):  
Cláudio M. Lousada ◽  
Pavel A. Korzhavyi
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Coordination Number ◽  
High Performance ◽  
Chemical Properties ◽  
Atomic Scale ◽  
Atomic Site ◽  
Segregation Energy ◽  
Physical Chemical ◽  
Symmetric Tilt

The segregation of P and S to grain boundaries (GBs) in fcc Cu has implications in diverse physical-chemical properties of the material and this can be of particular high relevance when the material is employed in high performance applications. Here, we studied the segregation of P and S to the symmetric tilt Σ9 (22¯1¯) [110], 38.9° GB of fcc Cu. This GB is characterized by a variety of segregation sites within and near the GB plane, with considerable differences in both atomic site volume and coordination number and geometry. We found that the segregation energies of P and S vary considerably both with distance from the GB plane and sites within the GB plane. The segregation energy is significantly large at the GB plane but drops to almost zero at a distance of only ≈3.5 Å from this. Additionally, for each impurity there are considerable variations in energy (up to 0.6 eV) between segregation sites in the GB plane. These variations have origins both in differences in coordination number and atomic site volume with the effect of coordination number dominating. For sites with the same coordination number, up to a certain atomic site volume, a larger atomic site volume leads to a stronger segregation. After that limit in volume has been reached, a larger volume leads to weaker segregation. The fact that the segregation energy varies with such magnitude within the Σ9 GB plane may have implications in the accumulation of these impurities at these GBs in the material. Because of this, atomic-scale variations of concentration of P and S are expected to occur at the Σ9 GB center and in other GBs with similar features.

Atomic-Scale Studies of Overlapping Grain Boundaries between Parallel and Quasi-Parallel Grains in Low-Symmetry Monolayer ReS2

Matter ◽  
2020 ◽  
Vol 3 (6) ◽  
pp. 2108-2123
Author(s):  
Shanshan Wang ◽  
Yue Yu ◽  
Shuqing Zhang ◽  
Shishu Zhang ◽  
Hua Xu ◽  
...  
Keyword(s):  
Grain Boundaries ◽  
Atomic Scale ◽  
Low Symmetry

scholarly journals New insights into microstructure of irradiated beryllium based on experiments and computer simulations

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
M. Klimenkov ◽  
P. Vladimirov ◽  
U. Jäntsch ◽  
V. Kuksenko ◽  
R. Rolli ◽  
...  
Keyword(s):  
Grain Boundaries ◽  
Gas Bubbles ◽  
Atomic Scale ◽  
Average Height ◽  
Secondary Phases ◽  
Atomistic Modelling ◽  
Transmission Electron ◽  
Intermetallic Precipitates ◽  
Diffusion Mechanisms ◽  
Small Bubbles

Abstract The microstructural response of beryllium after neutron irradiation at various temperatures (643–923 K) was systematically studied using analytical transmission electron microscope that together with outcomes from advanced atomistic modelling provides new insights in the mechanisms of microstructural changes in this material. The most prominent feature of microstructural modification is the formation of gas bubbles, which is revealed at all studied irradiation temperatures. Except for the lowest irradiation temperature, gas bubbles have the shape of thin hexagonal prisms with average height and diameter increasing with temperature. A high number density of small bubbles is observed within grains, while significantly larger bubbles are formed along high-angle grain boundaries (GB). Denuded zones (DZ) nearly free from bubbles are found along both high- and low-angle grain boundaries. Precipitations of secondary phases (mainly intermetallic Al-Fe-Be) were observed inside grains, along dislocation lines and at GBs. EDX analysis has revealed homogeneous segregation of chromium and iron along GBs. The observed features are discussed with respect to the available atomistic modelling results. In particular, we present a plausible reasoning for the abundant formation of gas bubbles on intermetallic precipitates, observation of various thickness of zones denuded in gas bubbles and precipitates, and their relation to the atomic scale diffusion mechanisms of solute-vacancy clusters.

Atomic-scale structural characterization of grain boundaries in epitaxial Ge/Si microcrystals by HAADF-STEM

2019 ◽  
Vol 167 ◽  
pp. 159-166
Author(s):  
Yadira Arroyo Rojas Dasilva ◽  
Rolf Erni ◽  
Fabio Isa ◽  
Giovanni Isella ◽  
Hans von Känel ◽  
...  
Keyword(s):  
Grain Boundaries ◽  
Structural Characterization ◽  
Atomic Scale

scholarly journals Hrem Of General And Twist Grain Boundaries

1999 ◽  
Vol 5 (S2) ◽  
pp. 108-109
Author(s):  
K. L. Merkle ◽  
L. J. Thompson
Keyword(s):  
Thin Film ◽  
Electron Beam ◽  
Phase Space ◽  
Grain Boundaries ◽  
Scale Structure ◽  
Zone Axis ◽  
Low Energy ◽  
Atomic Scale ◽  
Dimensional Phase Space ◽  
Scale Structures

The observation of atomic-scale structures of grain boundaries (GBs) via axial illumination HREM has been largely restricted to tilt GBs, due to the requirement that the electron beam be parallel to a low-index zone axis on both sides of the interface. This condition can be fulfilled for all tilt GBs with misorientation about a low-index direction. The information obtained through HREM studies in many materials has brought important insights concerning the atomic-scale structure of such boundaries. However, it is well known that tilt GBs occupy only an infinitesimally small fraction of the 5-dimensional phase space which describes the macroscopic geometry of all GBs. Therefore, although tilt GBs are very important due to their low energy, it would be usefulto also study twist GBs and general GBs that contain twist and tilt components.We have prepared thin-film Au samples by an epitaxy technique in which (01l) and (001) grains are grown side by side.

scholarly journals Atomic-scale Observation of Grains and Grain Boundaries in Monolayers of WS2

2014 ◽  
Vol 20 (S3) ◽  
pp. 1084-1085 ◽  
Author(s):  
Amin Azizi ◽  
Xiaolong Zou ◽  
Peter Ercuis ◽  
Zhuhua Zhang ◽  
Ana Laura Elias ◽  
...  
Keyword(s):  
Grain Boundaries ◽  
Atomic Scale

Survey of Grain Boundary Energies in Four Elemental Metals

2012 ◽  
Vol 715-716 ◽  
pp. 179-179
Author(s):  
David L. Olmsted ◽  
Elizabeth A. Holm ◽  
Stephen M. Foiles
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Energy Minimization ◽  
Boundary Energy ◽  
Atomic Scale ◽  
Energy Structure ◽  
Grain Boundary Energy ◽  
Fcc Metals ◽  
Composition And Structure ◽  
Boundary Properties

Grain boundary properties depend on both composition and structure. To test the relative contributions of composition and structure to the grain boundary energy, we calculated the energy of 388 grain boundaries in four elemental, fcc metals: Ni, Al, Au and Cu. We constructed atomic-scale bicrystals of each boundary and subjected them to a rigorous energy minimization process to determine the lowest energy structure. Typically, several thousand boundary configurations were examined for each boundary in each element.

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