The role of misfit dislocations in tilt boundary formation in heterosystems with nonsingular orientations

2014 ◽  
Vol 8 (4) ◽  
pp. 647-650 ◽  
Author(s):  
A. V. Kolesnikov ◽  
E. M. Trukhanov ◽  
A. S. Ilin ◽  
I. D. Loshkarev
Keyword(s):  
Tilt Boundary ◽  
Misfit Dislocations ◽  
Boundary Formation

Slip, twinning, and fracture at a grain boundary in the L12 ordered structure—AΣ = 9 tilt boundary

1988 ◽  
Vol 3 (5) ◽  
pp. 848-855 ◽  
Author(s):  
M. H. Yoo ◽  
A. H. King
Keyword(s):  
Intergranular Fracture ◽  
Local Stress ◽  
Boundary Region ◽  
Anisotropic Elasticity ◽  
Tilt Boundary ◽  
Microplastic Deformation ◽  
Ordered Structure ◽  
Local Stress Concentration ◽  
Boron Segregation

The role of interaction between slip dislocations and a Σ = 9 tilt boundary in localized microplastic deformation, cleavage, or intergranular fracture in the Li2 ordered structure has been analyzed by using the anisotropic elasticity theory of dislocations and fracture. Screw superpartials cross slip easily at the boundary onto the (1$\overline 1$1) and the (001) planes at low and high temperatures, respectively. Transmission of primary slip dislocations onto the conjugate slip system occurs with a certain degree of difficulty, which is eased by localized disordering. When the transmission is impeded, cleavage fracture on the ($\overline 1$11) plane is predicted to occur, not intergranular fracture, unless a symmetric double pileup occurs simultaneously. Absorption (or emission) of superpartials occurs only when the boundary region is disordered. Slip initiation from pre-existing sources near the boundary can occur under the local stress concentration. Implications of the present result on the inherent brittleness of grain boundaries in Ni3 Al and its improvement by boron segregation are discussed.

scholarly journals The Role of Current Sheet Scattering in the Proton Isotropic Boundary Formation During Geomagnetic Storms

2019 ◽  
Vol 124 (5) ◽  
pp. 3468-3486
Author(s):  
John D. Haiducek ◽  
Natalia Y. Ganushkina ◽  
Stepan Dubyagin ◽  
Daniel T. Welling
Keyword(s):  
Current Sheet ◽  
Geomagnetic Storms ◽  
Boundary Formation

The Role of Misfit Dislocation During Epitaxial Growth

1987 ◽  
Vol 94 ◽  
Author(s):  
D. Cherns
Keyword(s):  
Misfit Dislocation ◽  
Lattice Spacing ◽  
Minimum Energy ◽  
Energy Criterion ◽  
Misfit Dislocations ◽  
Metal Metal ◽  
Correct Account ◽  
Pseudomorphic Growth ◽  
Dislocation Sources

ABSTRACTThe theory of Frank and van der Merwe (FM) in 1949 showed that a minimum energy criterion could explain the pseudomorphic growth of a deposit on a substrate of different lattice spacing and the subsequent relief of strain by misfit dislocations as the deposit thickness increases. Although the “equilibrium” theory is qualitatively correct, account must be taken of actual dislocation sources, which may be complex, and which may be more or less efficient for misfit relief than predicted by the FM model. Moreover, misfit dislocation sources may determine the morphology of the growing film, the interface topology and even the atomic structure of the deposit/substrate interface. These various roles of misfit dislocations are reviewed here with examples from work on metal/metal, semiconductor/semiconductor and metal/semiconductor systems.

scholarly journals Role of radial glia in cytogenesis, patterning and boundary formation in the developing spinal cord

2005 ◽  
Vol 207 (3) ◽  
pp. 241-250 ◽  
Author(s):  
Kieran W. McDermott ◽  
Denis S. Barry ◽  
Siobhan S. McMahon
Keyword(s):  
Spinal Cord ◽  
Radial Glia ◽  
Boundary Formation ◽  
Developing Spinal Cord

scholarly journals Role of Cu film texture in grain growth correlated with twin boundary formation

2012 ◽  
Vol 60 (2) ◽  
pp. 588-595 ◽  
Author(s):  
Kazuyuki Kohama ◽  
Kazuhiro Ito ◽  
Takuya Matsumoto ◽  
Yasuharu Shirai ◽  
Masanori Murakami
Keyword(s):  
Grain Growth ◽  
Twin Boundary ◽  
Boundary Formation ◽  
Cu Film

Molecular Statics of a Ni/Zr Heterophase Interface

1993 ◽  
Vol 319 ◽  
Author(s):  
M. G. Fernandes ◽  
V. Pontikis ◽  
P.D. Bristowe
Keyword(s):  
Energy Minimization ◽  
Strain Field ◽  
Antisite Defect ◽  
Dislocation Network ◽  
Misfit Dislocations ◽  
Atomistic Model ◽  
Hexagonal Array ◽  
Strong Function ◽  
Defect Energies

AbstractAn atomistic model for a Ni/Zr hetero-interface formed between closed packed atomic planes is constructed and simulated using energy minimization techniques. The results show how misfit dislocations are introduced in the system and form an hexagonal array, and that the strain field in Ni can reach values two times larger than those in Zr. Calculated values for antisite defect energies are positive and are a strong function of position at the interface, reflecting the role of the dislocation network.

Role of the Surface Steps on the Growth of CrSi2 on {111} Silicon.

1995 ◽  
Vol 402 ◽  
Author(s):  
André M. Rocher ◽  
André Oustry ◽  
Marie José David ◽  
Michel Caumont
Keyword(s):  
Elastic Energy ◽  
Solid Phase ◽  
Misfit Dislocations ◽  
Solid Phase Epitaxy ◽  
Step Width ◽  
Orientation Relationships ◽  
Edge Type ◽  
Burgers Vector ◽  
Surface Steps

AbstractCrSi2 layers grown by solid phase epitaxy on a nominal (111) Si surface exhibit in the same proportion two different orientation relationships, named A and B. When CrSi2 is deposited on a 8° vicinal (111) Si surface, B-type orientation is favoured with respect to the A type. This result can be explained by the fact that both the step width introduced by the miscut and the planar coincidence between {1100}Crsi2 and {111}Si are nearly equal to 23Å. Edge type misfit dislocations are observed at the interface with the same spacing. Their Burgers vector component along [111] is almost compensated by the atomic steps along the <110> directions. The role of the steps is discussed in term of elastic energy. Steps introduce misfit dislocations which make possible coherent growth of the B type orientation.

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