Comparative modeling of the disregistry and Peierls stress for dissociated edge and screw dislocations in Al

The dislocation widths, Peierls barriers and Peierls stresses for shuffle screw dislocations in diamond structure crystals, Si and Ge, have been calculated by the improved P-N theory. The widths are about 0.6b, where b is the Burgers vector. The Peierls barrier for shuffle screw dislocation in Si and Ge, is about 3.61~4.61meV/Å and 5.31~13.32meV/Å, respectively. The Peierls stress is about 0.28~0.33GPa and 0.31~0.53GPa, respectively. The calculated Peierls barriers and stresses are likely the results of shuffle screw dislocation with metastable core which is centered on the bond between two atoms.

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Surface Effects on the Properties of Screw Dislocation in Nanofilms

Advances in Materials Science and Engineering ◽

10.1155/2017/6413495 ◽

2017 ◽

Vol 2017 ◽

pp. 1-9 ◽

Cited By ~ 1

Author(s):

Lili Liu ◽

Zhenya Meng ◽

Gang Xu ◽

Chenglin He ◽

Xiaozhi Wu ◽

...

Keyword(s):

Screw Dislocation ◽

Governing Equation ◽

Surface Effect ◽

Stacking Fault ◽

Peierls Stress ◽

First Principle ◽

Screw Dislocations ◽

The Core ◽

Core Width ◽

Stacking Fault Energies

The image dislocation method is used to construct the governing equation of dislocations in nanofilms. The classical Peierls-Nabarro equation can be recovered when the thickness of nanofilm is taken to be infinite. In order to determine the core width and Peierls stress of dislocations, the unstable stacking fault energies of Al and Cu nanofilms are calculated via the first-principle methods. It is found that surface effect can increase the Peierls stresses of screw dislocations in Al and Cu nanofilms.

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Influence of Shear Stress on Screw Dislocations in a Model Sodium Lattice

Canadian Journal of Physics ◽

10.1139/p71-262 ◽

1971 ◽

Vol 49 (16) ◽

pp. 2160-2180 ◽

Cited By ~ 192

Author(s):

Z. S. Basinski ◽

M. S. Duesbery ◽

Roger Taylor

Keyword(s):

Shear Stress ◽

First Principles ◽

Dislocation Core ◽

The Body ◽

Peierls Stress ◽

Screw Dislocations ◽

Hexagonal Close Packed ◽

Applied Shear Stress ◽

Dislocation Movement ◽

Twinning Direction

The behavior of the screw dislocation core in the presence of an external shear stress has been examined for the body-centered cubic and hexagonal close-packed phases of a model sodium lattice, using an effective ion–ion potential calculated from first principles. The Peierls stress for screw dislocations in the b.c.c. lattice at 0 °K is dependent on the orientation of the applied shear stress, and has a minimum value of 0.0105G, where G is the shear modulus, for slip in the twinning direction on {112} planes. The Peierls stress in the h.c.p. lattice is at least 25 times smaller. Dislocation movement in the model b.c.c. lattice takes place by unit translations on {110} planes, with the selection rule that no two consecutive translations can take place on the same slip plane.

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Peierls Stress for Screw Dislocations in Polyethylene

Journal of Applied Physics ◽

10.1063/1.1655887 ◽

1968 ◽

Vol 39 (11) ◽

pp. 4920-4928 ◽

Cited By ~ 28

Author(s):

James M. Peterson

Keyword(s):

Peierls Stress ◽

Screw Dislocations

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In situ Tensile Experiments at Low Temperatures on Niobium Single Crystals by H.V.E.M.

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100113913 ◽

1975 ◽

Vol 33 ◽

pp. 58-59

Author(s):

F. H. Louchet ◽

L. P. Kubin

Keyword(s):

Electron Microscope ◽

Transition Temperature ◽

Low Temperature ◽

Slip System ◽

Low Temperatures ◽

Tensile Axis ◽

Image Intensifier ◽

Screw Dislocations ◽

Source Operation

Experiments have been carried out on the 3 MeV electron microscope in Toulouse. The low temperature straining holder has been previously described Images given by an image intensifier are recorded on magnetic tape.The microtensile niobium samples are cut in a plane with the two operative slip directions [111] and lying in the foil plane. The tensile axis is near [011].Our results concern:- The transition temperature of niobium near 220 K: at this temperature and below an increasing difference appears between the mobilities of the screw and edge portions of dislocations loops. Source operation and interactions between screw dislocations of different slip system have been recorded.

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Observation of dislocations in dynamically loaded Cu-SiO2

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100143705 ◽

1986 ◽

Vol 44 ◽

pp. 424-425

Author(s):

D. S. Pritchard

Keyword(s):

Electron Microscope ◽

Strain Rate ◽

Single Crystal ◽

Transmission Electron Microscope ◽

Volume Fraction ◽

Screw Dislocations ◽

Spherical Inclusions ◽

Transmission Electron ◽

Crystal Dispersion ◽

Strain Rate Loading

The effect of varying the strain rate loading conditions in compression on a copper single crystal dispersion-hardened with SiO2 particles has been examined. These particles appear as small spherical inclusions in the copper lattice and have a volume fraction of 0.6%. The structure of representative crystals was examined prior to any testing on a transmission electron microscope (TEM) to determine the nature of the dislocations initially present in the tested crystals. Only a few scattered edge and screw dislocations were viewed in those specimens.

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