Formation of two edge dislocations in a grain due to interface disclination dipoles

2021 ◽  
pp. 1-8
Author(s):  
Jerome M. Colin
Keyword(s):  
Activation Energy ◽  
Inclination Angle ◽  
Edge Dislocation ◽  
Dislocation Dipole ◽  
Characteristic Parameters ◽  
Grain Sizes ◽  
Energy Variation ◽  
Edge Dislocations

Abstract The formation of a dipole of edge dislocations inside one grain separated from the adjacent grains by two interfaces in which are lying disclination dipoles (one in each interface) has been theoretically investigated from an energy variation calculation. Critical grain sizes associated with the formation of the edge dislocation dipole have been determined as well as an activation energy. The effects of the inclination angle of the gliding plane of the dislocations and the characteristic parameters of the disclination dipoles have been finally analyzed.

Computer Simulation of Creation and Motion of Edge Dislocations in Face Centered Crystals

1994 ◽  
Vol 356 ◽  
Author(s):  
N. Tajima ◽  
T. Nozaki ◽  
T. Hirade ◽  
Y. Kogure ◽  
Masao Doyama
Keyword(s):  
Molecular Dynamics ◽  
Computer Simulation ◽  
Edge Dislocation ◽  
Embedded Atom ◽  
Small Crystals ◽  
Face Centered ◽  
Edge Dislocations

AbstractComplete and dissociated edge dislocations were created near the center of the surface (101) of aluminum small crystals whose surfaces are (111), (111), (101), (101). (121) and (121). Molecular dynamics with N-body embedded atom potentials were used. Higher stress is needed to create a complete edge dislocation than to create a dissociated dislocation.

Basal Plane Dislocation Multiplication via the Hopping Frank-Read Source Mechanism and Observations of Prismatic Glide in 4H-SiC

2012 ◽  
Vol 717-720 ◽  
pp. 327-330 ◽  
Author(s):  
Huan Huan Wang ◽  
Sha Yan Byrapa ◽  
F. Wu ◽  
Balaji Raghothamachar ◽  
Michael Dudley ◽  
...  
Keyword(s):  
Shear Stress ◽  
Slip Plane ◽  
Opposite Direction ◽  
Edge Dislocation ◽  
Basal Plane ◽  
Detailed Mechanism ◽  
Slip Planes ◽  
Basal Plane Dislocation ◽  
Edge Dislocations ◽  
Dislocation Multiplication

In this paper, we report on the synchrotron white beam topographic (SWBXT) observation of “hopping” Frank-Read sources in 4H-SiC. A detailed mechanism for this process is presented which involves threading edge dislocations experiencing a double deflection process involving overgrowth by a macrostep (MP) followed by impingement of that macrostep against a step moving in the opposite direction. These processes enable the single-ended Frank-Read sources created by the pinning of the deflected basal plane dislocation segments at the less mobile threading edge dislocation segments to “hop” from one slip plane to other parallel slip planes. We also report on the nucleation of 1/3< >{ } prismatic dislocation half-loops at the hollow cores of micropipes and their glide under thermal shear stress.

On the formation of vacancies by edge dislocation dipole annihilation in fatigued copper

2011 ◽  
Vol 33 (10) ◽  
pp. 1369-1375 ◽  
Author(s):  
Steffen Brinckmann ◽  
Rakulan Sivanesapillai ◽  
Alexander Hartmaier
Keyword(s):  
Edge Dislocation ◽  
Dislocation Dipole

Atomistic Modeling and Simulation of Impurity Atmosphere in Silicon and Edge Dislocation Locking Effects

2004 ◽  
Vol 810 ◽  
Author(s):  
A. Karoui
Keyword(s):  
Edge Dislocation ◽  
Theoretical Study ◽  
Dislocation Core ◽  
Atomic Fraction ◽  
Atomistic Modeling ◽  
Self Energy ◽  
Occupancy Probability ◽  
Effect Model ◽  
Dopant Atoms ◽  
Edge Dislocations

ABSTRACTA theoretical study of edge dislocation locking by impurities in silicon is presented. Three groups of impurities are considered: (i) light atoms O, N, and C., (ii) large atoms Ga, and Ge, and (iii) small dopant atoms B, P, and Al. Based on impurity size effect model, these three groups produce distinct different dislocation locking effects. Atoms from the first group strongly bind with edge dislocations. The O, N, and C atmospheres are similar, with a slightly stronger occupancy probability for O and N in the vicinity of the dislocation core. For the second group, Ge loosely binds to dislocation and resists at most 1/3 of the separation shear stress that the first group can withstand. Germanium has only a small chance to reach the dislocation core. The third impurity group does not resist shear any separation stress from edge dislocations. Moreover, B and P atoms can not be trapped at all by edge dislocations. At a local atomic fraction of 10−4, edge dislocation-impurity binding energy varies from 0.008 eV/Å for P to 1.7 eV/Å for N and 1. 8 eV/Å for O. In addition, using molecular mechanics on system of 34552 atoms the self-energy of an edge dislocation was calculated and found equal to 156 meV/Å.

Study of Dislocation Densities of Thick GaN Films

2014 ◽  
Vol 989-994 ◽  
pp. 387-390
Author(s):  
Yon Gan Li ◽  
Xiang Qian Xiu ◽  
Xue Mei Hua ◽  
Shi Ying Zhang ◽  
Shi Pu Gu ◽  
...  
Keyword(s):  
High Resolution ◽  
Dislocation Density ◽  
Screw Dislocation ◽  
Edge Dislocation ◽  
Thick Films ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dislocation Densities ◽  
Edge Dislocations

The dislocation density of GaN thick films has been measured by high-resolution X-ray diffraction. The results show that both the edge dislocations and the screw dislocation reduce with increasing the GaN thickness. And the edge dislocations have a larger fraction of the total dislocation densities, and the densities for the edge dislocation with increasing thickness reduce less in contrast with those for the screw dislocation.

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