The study of faulted dipoles in copper using weak-beam electron microscopy

Carter, C. B.; Holmes, S. M.

doi:10.1080/14786437508220883

Cited by 41 publications

(4 citation statements)

References 19 publications

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“…When vacancy diffusion is not favored by temperature, the transformed configurations with linear shapes, as shown in Al, require larger breaking force compared with the classical dislocation dipoles (see figure 9 in [15]). The 60 • faulted dipole has the lowest energy among all the orientations (figure 6) and thus is frequently observed [35][36][37], although such dipoles anneal out at high temperatures. At intermediate temperatures, as indicated in figure 12, the clustering process can take up to seconds forming point-defectlike debris, including various vacancy clusters, SFTs, etc, whose stability is indicated by the experimental observation of the profuse existence of point defect clusters in a number of fcc metals and alloys after quenching or deformation [38,39].…”

Section: Long-term Stability Of the Resulting Debrismentioning

confidence: 88%

Atomistic investigation of the annihilation of non-screw dislocation dipoles in Al, Cu, Ni andγ-TiAl

Wang

Rodney

et al. 2013

Modelling Simul. Mater. Sci. Eng.

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Annihilation of vacancy-type non-screw dipolar dislocations is studied with molecular dynamics in fcc metals Al, Cu and Ni, and intermetallic γ-TiAl. Contrary to common belief, dipoles do not simply disappear. Instead, they transform into a series of defects depending on their height, orientation and temperature. At low temperatures, hollow structures, reconstructed configurations and faulted dipoles are formed. At high temperatures, with the help of short-range diffusion, isolated or interconnected vacancy clusters and stacking-fault tetrahedra are formed within a simulation time of 1 ns. Employing saddle-point-search methods, the formation of the above by-products is explained by accelerated diffusion paths along the dipole cores.

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Section: Long-term Stability Of the Resulting Debrismentioning

confidence: 88%

Atomistic investigation of the annihilation of non-screw dislocation dipoles in Al, Cu, Ni andγ-TiAl

Wang

Rodney

et al. 2013

Modelling Simul. Mater. Sci. Eng.

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“…Dissociated faulted dipoles were studied in detail in silicon and germanium (Winter et al, 1977;Sato, 1983) and in f.c.c. metals (Antonopoulos & Winter, 1976;Carter &? Holmes, 1975, 1977Cockayne et al, 1971).…”

Section: T H E D E T E R M I N a T I O N Of T H E Parameters O F Dissmentioning

confidence: 99%

A review of the determination of dislocation parameters using strong‐ and weak‐beam electron microscopy

Nikolaichick

Khodos

1989

Journal of Microscopy

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SUMMARY This paper reviews the results of the investigation of dislocation image characteristics as formed using strong‐ and weak‐beam transmission electron microscopy as well as the application of these data for the determination of the basic dislocation parameters: the value, direction and sign of the Burgers vector, and the dissociation width of dislocations split into Shockley partials. The relative advantages and limitations of strong‐ and weak‐beam techniques in studies of dislocation parameters are discussed. This is exemplified by an examination of the possibility of revealing dislocation dissociation with separation Δ 10 nm using strong diffracted beams. The influence of the anisotropy of the elastic moduli on the strong‐beam images of dissociated dislocations is also discussed. The effects of the column approximation on the calculated weak‐beam images of dissociated dislocations are analysed using the results of non‐column calculations. The statistical analysis of the measured dissociation values is also described, allowing the enhancement of the precision of the weak‐beam measurements and their sensitivity in revealing small variations in dissociation width. Finally, the differences in the form of weak‐beam images of dissociated dislocations and of ordinary and faulted dipoles are discussed.

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“…Because of the relatively simple interpretation of multipole diffraction patterns that the above properties imply it seemed likely that a study of the diffraction patterns and images of dislocation multipoles could provide a critical test of the accuracy with which a periodic strain field can be characterized from the diffraction pattern fine structure. Wintner & Karnthaler (1978) have shown that in Cu-A1 alloys some or all of the dipoles in dislocation multipoles may exist as faulted dipoles (Hirsch, 1963;Seeger, 1964;Steeds, 1967;Carter & Holmes, 1975). When this occurs two of the partial dislocations are replaced by stairrod dislocations and a stacking fault on the inclined plane.…”

Section: Introductionmentioning

confidence: 99%

The characterization of periodic dislocation arrays from the fine structure of electron diffraction patterns

Morton¹

1981

Journal of Microscopy

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SUMMARY The accuracy of the technique of using the fine‐structure observed in electron diffraction patterns to determine the periodicity and characteristic direction associated with a periodic strain field is assessed. This is done by applying the technique to dislocation multipoles which have a strain field with only a single periodic component and which can be well characterized by other means. It is shown that, for such a single‐component strain field, precision measurement of the diffraction patterns combined with numerical analysis of the data allows the determination of the direction and spacing characterizing the strain field with an accuracy of about 0.25° to 1.0° in direction (depending upon periodicity) and ± 2% in spacing. This is better than can usually be achieved from measurements of corresponding features in the electron micrographs.

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The study of faulted dipoles in copper using weak-beam electron microscopy

Cited by 41 publications

References 19 publications

Atomistic investigation of the annihilation of non-screw dislocation dipoles in Al, Cu, Ni andγ-TiAl

Atomistic investigation of the annihilation of non-screw dislocation dipoles in Al, Cu, Ni andγ-TiAl

A review of the determination of dislocation parameters using strong‐ and weak‐beam electron microscopy

The characterization of periodic dislocation arrays from the fine structure of electron diffraction patterns

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