Lattice strain and lattice misfit calculation using CBED technique in TEM - possibilities and limitations

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F26722445%3A_____%2F23%3AN0000123" target="_blank" >RIV/26722445:_____/23:N0000123 - isvavai.cz</a>

Result on the web

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DOI - Digital Object Identifier

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Result language

angličtina

Original language name

Lattice strain and lattice misfit calculation using CBED technique in TEM - possibilities and limitations

Original language description

Generally, lattice constants of crystalline materials are established by using X-rays, neutrons and electrons. Precise lattice constants are determined from X-ray and neuron diffraction techniques. However, to determine lattice constants changes in a local region in the material, then electron diffraction is a right choice. Determining lattice parameters is essential in some aspects of materials science, i.e., phase identification, phase diagram determinations and misfit strain measurement (which is an important parameter in modeling of mechanical behavior of the alloys). It is common to see peak/spot broadening in diffraction patterns. Which is associated with the presence of defects in the crystal and elastic strain. Therefore, it is important to realize that the presence of elastic strain or a population of defects associated with the strain, leads to the broadening of any diffraction maxima. Thus, electron diffractions techniques may be used (like X-rays and neutrons) to measure strain but in a more local sense. The elastic strain or strain caused by the presence of defects or second phase particles/precipitates in the lattice can be measured from convergent beam electron diffraction (CBED) technique in transmission electron microscopy. The major advantages of using a convergent probe are the small volume from which the diffraction pattern is excited. The diffraction pattern consisting of discs rather than the spots normally observed in conventional selected area diffraction pattern (SAED). The information contains in these disks are very precise and three dimensional. Within these zero-order Laue zone (ZOLZ) discs, under suitable circumstances, a fine structure resulting from diffraction of incident electrons from upper layers of the reciprocal lattice. This fine structure is due to elastically scattered electrons by planes not contained within the zone axis under observation and is therefore referred to as high-order Laue zone (HOLZ) lines. These are in fact defect lines because the incident electrons undergoing diffraction are directed away from ZOLZ disc. The HOLZ lines contain the most precise information on orientation and lattice parameter. Diffraction from high-order Laue zones involves large g-vectors, the fine structure formed by the HOLZ lines is extremely sensitive to the small changes in the lattice parameter. ztoku. Zpráva CVŘ-5103.

Czech name

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Czech description

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Type

O - Miscellaneous

CEP classification

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OECD FORD branch

20501 - Materials engineering

Project

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Continuities

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Publication year

2023

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů