scholarly journals Direct observation of dislocation structure evolution in SRF cavity niobium using electron channeling contrast imaging

2018 ◽  
Vol 124 (15) ◽  
pp. 155105
Author(s):  
M. Wang ◽  
D. Kang ◽  
T. R. Bieler
Keyword(s):  
Direct Observation ◽  
Dislocation Structure ◽  
Structure Evolution ◽  
Contrast Imaging ◽  
Electron Channeling ◽  
Srf Cavity

Rotational-Electron Channeling Contrast Imaging analysis of dislocation structure in fatigued copper single crystal

2019 ◽  
Vol 162 ◽  
pp. 103-107 ◽  
Author(s):  
G. L'hôte ◽  
C. Lafond ◽  
P. Steyer ◽  
S. Deschanel ◽  
T. Douillard ◽  
...  
Keyword(s):  
Single Crystal ◽  
Dislocation Structure ◽  
Copper Single Crystal ◽  
Imaging Analysis ◽  
Contrast Imaging ◽  
Electron Channeling

Rapid misfit dislocation characterization in heteroepitaxial III-V/Si thin films by electron channeling contrast imaging

2014 ◽  
Vol 104 (23) ◽  
pp. 232111 ◽  
Author(s):  
Santino D. Carnevale ◽  
Julia I. Deitz ◽  
John A. Carlin ◽  
Yoosuf N. Picard ◽  
Marc De Graef ◽  
...  
Keyword(s):  
Thin Films ◽  
Misfit Dislocation ◽  
Contrast Imaging ◽  
Electron Channeling

scholarly journals Quantitative misfit dislocation characterization with electron channeling contrast imaging

2021 ◽  
Vol 27 (S1) ◽  
pp. 912-914
Author(s):  
Ari Blumer ◽  
Marzieh Baan ◽  
Zak Blumer ◽  
Jacob Boyer ◽  
Tyler J. Grassman
Keyword(s):  
Misfit Dislocation ◽  
Contrast Imaging ◽  
Electron Channeling

scholarly journals Coincident Electron Channeling and Cathodoluminescence Studies of Threading Dislocations in GaN

2013 ◽  
Vol 20 (1) ◽  
pp. 55-60 ◽  
Author(s):  
Gunasekar Naresh-Kumar ◽  
Jochen Bruckbauer ◽  
Paul R. Edwards ◽  
Simon Kraeusel ◽  
Ben Hourahine ◽  
...  
Keyword(s):  
Structural Damage ◽  
Light Emission ◽  
Threading Dislocations ◽  
Nonradiative Recombination ◽  
Contrast Imaging ◽  
Force Microscopy ◽  
Electron Channeling ◽  
Microscopy Techniques ◽  
Cathodoluminescence Imaging ◽  
Edge Dislocations

AbstractWe combine two scanning electron microscopy techniques to investigate the influence of dislocations on the light emission from nitride semiconductors. Combining electron channeling contrast imaging and cathodoluminescence imaging enables both the structural and luminescence properties of a sample to be investigated without structural damage to the sample. The electron channeling contrast image is very sensitive to distortions of the crystal lattice, resulting in individual threading dislocations appearing as spots with black–white contrast. Dislocations giving rise to nonradiative recombination are observed as black spots in the cathodoluminescence image. Comparison of the images from exactly the same micron-scale region of a sample demonstrates a one-to-one correlation between the presence of single threading dislocations and resolved dark spots in the cathodoluminescence image. In addition, we have also obtained an atomic force microscopy image from the same region of the sample, which confirms that both pure edge dislocations and those with a screw component (i.e., screw and mixed dislocations) act as nonradiative recombination centers for the Si-doped c-plane GaN thin film investigated.

Microcrack Nucleation and Crack Propagation in Equiaxed γ TiAl

2002 ◽  
Vol 753 ◽  
Author(s):  
Martin A. Crimp ◽  
Boon-Chi Ng ◽  
Benjamin A. Simkin ◽  
Thomas R. Bieler
Keyword(s):  
Ex Situ ◽  
Contrast Imaging ◽  
Active Deformation ◽  
Electron Channeling ◽  
Microcrack Initiation ◽  
Grain Orientations ◽  
Contrast Analysis ◽  
Defect Imaging

ABSTRACTTo gain a better understanding of the ductility limitations in TiAl alloys, the mechanisms involved in deformation strain transfer and/or microcrack initiation at grain boundaries have been examined in an equiaxed near-γ alloy. These studies have been carried out on both in-situ and ex-situ deformed bulk samples using scanning electron microscopy (SEM) techniques for both orientation analysis and deformation defect imaging. Selected area electron channeling patterns (SACPs) have allowed determination of grain orientations, eliminating ambiguity between the a and c axes. Deformation twins and dislocations have been imaged in the bulk samples using electron channeling contrast imaging (ECCI). A combination of ECCI contrast analysis and trace analysis based on orientations determined from SACP has allowed identification of the active deformation systems. Microcracks have been found to initiate at γ-γ boundaries as a result of an inability to adequately transfer twin strain from grain to grain. Once initiated, cracks propagate through cleavage and re-nucleation of grain boundary microcracks in front of the advancing crack. A geometric based predictive factor has been developed that accounts for microcrack initiation at γ-γ boundaries based in deformation twinning and strain accommodation by ordinary dislocations.

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