Creation of Dislocations in a Shall Copper Single Crystal

1992 ◽  
Vol 278 ◽  
Author(s):  
Masao Doyama
Keyword(s):  
Single Crystal ◽  
Yield Stress ◽  
Partial Dislocation ◽  
Stacking Fault ◽  
Copper Single Crystal ◽  
Shockley Partial ◽  
Partial Dislocations ◽  
Edge Dislocations

AbstractEdge dislocations were created on a surface of a small copper single crystal. Very sharp yield stress was observed when a partial dislocation was created. Edge dislocations in copper were split into Heidenreich–Shockley partial dislocations connected with the stacking fault.

Plastic Deformation of Thin Films – Bending

2001 ◽  
Vol 695 ◽  
Author(s):  
T. Nozaki ◽  
Y. Kogure ◽  
Masao Doyama
Keyword(s):  
Thin Films ◽  
Molecular Dynamics ◽  
Plastic Deformation ◽  
Single Crystal ◽  
Atomic Potential ◽  
Shockley Partial ◽  
Partial Dislocations ◽  
Extended Surface ◽  
Edge Dislocations

ABSTRACTWidely accepted model of bending of a single crystal suggests that edge dislocations are introduced from both the compressed surface and extended surface. The present study examined this model by molecular dynamics using an embedded potential. Shockley partial dislocations are created on the compressed surface. Due to the characteristics of inter atomic potential, the stress on the compression surface is higher than that on the extended surface.

Creation and Motion of Edge Dislocations in Copper Single Crystals

1997 ◽  
Vol 505 ◽  
Author(s):  
Masaodoyama ◽  
Yoshiaki Kogure ◽  
Tadatoshi Nozaki
Keyword(s):  
Molecular Dynamics ◽  
Single Crystals ◽  
Partial Dislocation ◽  
Stacking Fault ◽  
Shockley Partial Dislocation ◽  
Shockley Partial ◽  
Small Crystals ◽  
The Creation ◽  
Copper Single Crystals ◽  
Edge Dislocations

ABSTRACTDislocations were created near the center of the surface (110) of copper small crystals whose surfaces are (111), (111), (110), (110), (112), and (112) by use of n-body atom potentials and molecular dynamics. At first, a Heidenreich-Shockley partial dislocation was created. As the partial dislocation proceeds, the partial dislocation and the surface was connected with a stacking fault until the next Heidenreich-Shockley partial dislocation was created at the surface.Just before the creation of a partial dislocation the stress was the highest. For larger crystals, forming a step on (110) plane was not enough and a shear was necessary to move dislocations.

scholarly journals Shrinking stacking fault through glide of the Shockley partial dislocation in hard-sphere crystal under gravity

2007 ◽  
Vol 105 (10) ◽  
pp. 1377-1383 ◽  
Author(s):  
Atsushi Mori ◽  
Yoshihisa Suzuki ◽  
Shin-Ichiro Yanagiya ◽  
Tsutomu Sawada ◽  
Kensaku Ito
Keyword(s):  
Hard Sphere ◽  
Partial Dislocation ◽  
Stacking Fault ◽  
Shockley Partial Dislocation ◽  
Shockley Partial

Effect of Ta on the Structure and Dynamics of γ/α2 Interfaces in Tial

1990 ◽  
Vol 213 ◽  
Author(s):  
S. R. Singh ◽  
J. M. Howe
Keyword(s):  
Partial Dislocation ◽  
Growth Mechanisms ◽  
Tial Alloys ◽  
Shockley Partial ◽  
Structure And Dynamics ◽  
Partial Dislocations ◽  
Α2 Phase ◽  
Atomically Flat ◽  
Ledge Mechanism ◽  
Image Simulations

ABSTRACTThe structure of γ/α interfaces in binary and Ta-containing TiAl alloys were analyzed by HRTEM and image simulations. Growth of α2 was found to be due to a ledge mechanism, consisting of Shockley partial dislocations on alternate (111)γ planes. The interface is atomically flat between the ledges and addition of Ta was found to transform arrays of growth ledges in the binary alloy into islands on the plate faces in the Ta-containing alloy. These islands of α2 on the γ/α2 interfaces were 4–7nm wide and increased in size with decreasing ageing temperature. The height of the ledges and islands were always a multiple of the c-parameter (0.46nm) of the α2 phase. The islands were bounded by 90°(edge) and 30° screw) Shockley partial dislocations. The 30° partial dislocation cores were localized whereas the 90° partial dislocation cores appeared to be highly delocalized due to presence of a high density of kinks, which in one case was found to be about 0.65nm−1.These results are interpreted in terms of the growth mechanisms and morphology of the α2 phase.

Dislocation Structure Analysis of Low Angle Tilt Grain Boundaries in Alumina by Elastic Theory

2007 ◽  
Vol 561-565 ◽  
pp. 2465-2468
Author(s):  
Atsutomo Nakamura ◽  
E. Tochigi ◽  
Naoya Shibata ◽  
Takahisa Yamamoto ◽  
Yuichi Ikuhara
Keyword(s):  
Grain Boundaries ◽  
Structure Analysis ◽  
Dislocation Structure ◽  
Stacking Fault ◽  
Elastic Theory ◽  
Partial Dislocations ◽  
Edge Dislocations ◽  
Fault Region

Structure and configuration of boundary dislocations on the low angle tilt grain boundaries in alumina were considered based on the ideas that the boundary is composed of regularly arrayed edge dislocations and that the dislocations could dissociate into partial dislocations as well as glide dislocations in bulk. Moreover, the structure of the dissociated boundary dislocations were evaluated by the calculations based on an elastic theory. The calculations indicated that the largeness of the stacking fault region between partial dislocations formed by the dissociation will decrease with increasing tilt angles. It can be said that the idea and calculations used here will be powerful in considering the dislocation structure of low angle tilt grain boundaries that are not or are difficult to be identified.

Observation of dislocation reactions in CDTE at lattice resolution

1983 ◽  
Vol 41 ◽  
pp. 112-113
Author(s):  
T. Yamashita ◽  
R. Sinclair
Keyword(s):  
Partial Dislocation ◽  
Video Recording ◽  
Dislocation Motion ◽  
Video Tape ◽  
Exposure Rate ◽  
Shockley Partial Dislocation ◽  
Shockley Partial ◽  
Partial Dislocations ◽  
Lattice Resolution ◽  
Obvious Extension

Recently, lattice resolution video-recording of dislocation motion in CdTe has been reported by Sinclair et al, using the Cambridge 500 keV microscope equipped with a TV camera. Phenomena such as the motion of Shockley partial dislocations and climb of Frank dislocations were recorded onto a video tape which has an exposure rate of 50 half-frames per second. An obvious extension of this work is to study the dislocation reactions. An example of such a reaction which was detected in CdTe is shown in Fig. 1. The micrographs were taken several seconds apart in a JEOL 200CX microscope, and they show dissociation of a Frank dislocation into a Shockley partial dislocation and a Lomer dislocation (ie., a sessile lock).

Localized Influence of Solute on the Stacking Fault Energy of Dilute Al-Based Solid Solutions

1993 ◽  
Vol 319 ◽  
Author(s):  
C. Lane Rohrer
Keyword(s):  
Solid Solutions ◽  
Partial Dislocation ◽  
Binary Systems ◽  
Stacking Fault ◽  
Stacking Fault Energy ◽  
Dislocation Dipole ◽  
Partial Dislocations ◽  
Pure Metals ◽  
Small Clusters ◽  
Dislocation Spacing

AbstractThe stacking fault energy (SFE) is widely used to classify the mechanical behavior of pure metals. In alloys, however, the experimentally observed SFE is strongly influenced by localized solute effects. To further understand these effects on dislocation structure and on the observed SFE, solute segregation to an extended edge dislocation dipole, delineating two stacking faults, was studied in dilute Al:Cu, Al:Ag, and Al:Cu, Ag solid solutions. Cu and Ag were chosen to isolate solute size and modulus effects, Cu being smaller than Al, while Ag and Al are essentially the same size. Atomistic Monte Carlo results showed little change in the partial dislocation spacing in the binary systems as compared to the spacing in pure Al, even though Cu was observed to segregate to the compressive regions of the dislocation dipoles, forming widespread atmospheres, while Ag formed randomly distributed Ag-rich zones. However, in ternary Al:Cu,Ag simulations, the Ag apparently inhibited the Cu from distributing across the width of the extended dislocations, both Ag and Cu forming small clusters near or on the partial dislocations which increased the partial dislocation spacing. Results will be discussed in light of interpretations of experimental SFE determinations, emphasizing the importance of the localized solute distribution on the SFE.

Yield stress of a copper single crystal containing B2O3 particles

1990 ◽  
Vol 25 (1) ◽  
pp. 220-222 ◽  
Author(s):  
Susumu Onaka ◽  
Satoshi Soeta ◽  
Masaharu Kato
Keyword(s):  
Single Crystal ◽  
Yield Stress ◽  
Copper Single Crystal
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