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 lattice dislocations

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updated Wed. May 2, 2018

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Further investigation revealed that these nanoprecipitates were coherent with the host, meaning that the crystal lattice planes were continuous as they passed through the ... Failure of brittle materials, such as calcite, occurs via a different mechanism than in metals, as dislocation mobility is limited.
Dislocation-slip (where lattice dislocations are generated and move) and twinning (where sub-grains form with a mirror-image lattice) are the basic mechanisms of plastic deformation. Despite their fundamental importance to plasticity, diagnosing the active mechanism in-situ (during the shock) has been ...

... problems arising from threading dislocations in lattice-mismatched crystal ... A 500°C superlattice dislocation filter in the form of 10 layers of ...
This snapshot depicts a dense network of lattice defects developing in the flowing ... dislocations in the crystal lattice whose motion results in material ... has focused on dislocation interactions and their role in metal hardening, ...
Strength and plasticity properties of a metal are defined by dislocations, line defects in the crystal lattice whose motion causes material slippage along crystal planes. The theory of crystal dislocation was first advanced in the 1930s, and much research since then has focused on dislocation interactions and ...
... the crystal lattice away from body centered cubic and resulting in a high density of dislocations, the main cause of strengthening of the steel.

This snapshot depicts a dense network of lattice defects developing in the ... of a metal are defined by dislocations, line defects in the crystal lattice whose ... The theory of crystal dislocation was first advanced in the 1930s, and ...
Then further GaAs was grown including 15 periods of Al0.3Ga0.7As∕GaAs (5/5nm) superlattice for annihilating the threading dislocations.
Dislocations in crystals are places where the orderly three-dimensional structure of a crystal lattice—whose arrangement of atoms repeats ... to explaining phonon-dislocation interactions, Li explains, and a few other questions ...
For metal-containing materials, the governing defects are generally present as linear dislocations in the lattice- a primary carrier of shear.
Dislocation mobility in uranium dioxide at high temperatures and under ... viz., point defects, line defects (dislocations), planar defects and bulk defects. ... Uranium atoms on lattice points of the perfect uranium sublattice within ...
Dislocations are atomic-scale lattice defects that play a central role in determining the properties of crystalline materials. For example, they ...
X-rays can penetrate crystals and the lattice structures of metals and ... and often nano-precipitates that pin dislocations in the lattice, which ...
Lattice mismatches between high-Al-content AlGaN and the substrate are smaller on AlN, compared with GaN. Growing nanocolumns can ...
"In some years you will get a dislocation around costs maybe and we ... an acquisition of Lattice, which has a book value of about $1.3 billion.
Yet somehow, they've turned this dislocation into uncanny brilliance. ... from their lattice-like arrangements, and free to steer proceedings.
The dislocations move through the crystal lattice, creating more dislocations as they go and tangling up on each other. The motion of these ...

These defects create imperfections in the lattice of atoms inside a ... to see the network of dislocations, this is an exciting technique," added ...
These defects create imperfections in the lattice of atoms inside a grain ... to examine deformations and dislocations that affect their properties.
The atoms tend to arrange themselves in a perfect cubic symmetry, and strain builds up within the lattice when this arrangement is disturbed.
Metal contains defects called dislocations, places where the planes of the metal's atomic lattice become irregular, rather than repeating perfectly. ... depends on the conditions on the surface, including the dislocation density.
Even though the nanocrystals have dislocations, compressing these crystals ... dislocations out of the material, reducing the dislocation density by fifteen ... of the cracking and slipping the organized lattices within the atoms3.
New research offers insights into how crystal dislocations -- a common type of ... These defects have a strong effect on phonons, the modes of lattice ... But a precise understanding of the mechanism of the dislocation-phonon ...
Dislocations in crystals are places where the orderly three-dimensional structure of a crystal lattice—whose arrangement of atoms repeats ... to explaining phonon-dislocation interactions, Li explains, and a few other questions ...
For metal-containing materials, the governing defects are generally present as linear dislocations in the lattice- a primary carrier of shear.
Dislocation mobility in uranium dioxide at high temperatures and under ... viz., point defects, line defects (dislocations), planar defects and bulk defects. ... Uranium atoms on lattice points of the perfect uranium sublattice within ...
This maintains lattice coherency without large stresses that may otherwise produce misfit dislocations or form unintended secondary phases.
Dislocations are atomic-scale lattice defects that play a central role in determining the properties of crystalline materials. For example, they ...
Relative orientation of crystalline lattice and incident electron beam influence ... useful for imaging crystallographic defects such as dislocations, ...
Then further GaAs was grown including 15 periods of Al0.3Ga0.7As∕GaAs (5/5nm) superlattice for annihilating the threading dislocations.
For metal-containing materials, the governing defects are generally present as linear dislocations in the lattice- a primary carrier of shear.
The starting point for Aalto University's researchers Jori Lemettinen and Sami Suihkonen was that the use of SOI substrate had been suggested as having the ability to alleviate the detrimental effects of lattice and thermal mismatches and to absorb ...
If a silicon epitaxial layer is grown on a SiGe substrate, then the lattice mismatch creates biaxial tensile stress in the layer, and the greater the Ge content, the greater the stress.
For many integrated circuit and high speed transistor applications the strain in the epitaxial layers of a semiconductor is relieved by introducing misfit dislocations that has inherent strain in their lattice structure. Therefore, controlling the ...
Specifically, these defects - holes or threading dislocations where atoms should be - destroy the properties of the 2D electron gas channel in the device.
"When you grow the GaN on top, there's a lot of strain between the layers, so we grew buffer layers [between the silicon and GaN] to help change the lattice constant into the proper size," explained ECE undergraduate lead researcher Josh Perozek, lead ...
When crystals are deformed, defects called dislocations form and move through the lattice to shuttle the atoms around.
Direct integration of III-V materials on silicon should reduce process complexity and cost, but lattice mismatching reduces material quality and reduces the possibilities for efficient light emission, particularly for lasers.
In addition, germanium (Ge) buffers are often used to accommodate lattice mismatching of III-V heterostructures with Si, but Ge on offcut Si is generally of low quality.
... aluminium gallium nitride (AlGaN) and aluminium nitride buffer interlayers to manage the differences in lattice parameter (~17%) and coefficient of thermal expansion (CTE ~ 54%) between Si and GaN that lead to threading dislocations (TDs) and cracking.
Or did the strong binding of gallium and nitrogen atoms to their lattice sites render the atoms more difficult to displace?
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Top: Aspartic acid molecules embedded in a crystalline lattice. Middle: A dislocation in the crystal, represented by the black line, gets hung up on the molecules.
As the atoms of the different elements are distributed along the positions in the crystal lattices of these materials without any identifiable order and the entropy is, to a certain extent, a measure for the disorder, the materials are called high ...
Figure 17 - Rogers' hypothetical crystal of metal containing no dislocations. ... The lattice spacing on the surface of such NaCl crystals is about 6% smaller than the spacing in the solid crystal, resulting in a tendency for the surface to contract ...
... attracted much attention because of their low fabrication cost. These GaN-based LEDs, however, tend to include high densities of dislocations and cracks because of the large mismatch of lattice constants and thermal expansion coefficients between ...
... attracted much attention because of their low fabrication cost. These GaN-based LEDs, however, tend to include high densities of dislocations and cracks because of the large mismatch of lattice constants and thermal expansion coefficients between ...
In this study we question this assumption by showing that fast processes (including many sub-excitations possibly due to lattice distortions or dislocations) involved in the structure of fast-moving crack tips induce a "frozen" regime where - for a ...
This concept is known to gradually fail with increasing complexity of the micro-structure and macroscopic plastic deformation (giving rise to increasing values of intragranular orientation spread and lattice strain) and eventually results in non ...
In his work, Li has developed a new quantum theory of dislocation to allow the study of dislocations on materials' non-mechanical properties from a fundamental Hamiltonian level.


 

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