Examination of Dislocation Cores in Ni3Al Using High Resolution Electron Microscopy

1988 ◽  
Vol 133 ◽  
Author(s):  
Martin A. Crimp ◽  
P. M. Hazzledine
Keyword(s):  
Electron Microscopy ◽  
Computer Simulation ◽  
High Resolution ◽  
Yield Strength ◽  
Deformation Temperature ◽  
Dislocation Core ◽  
High Resolution Electron Microscopy ◽  
The Core ◽  
Resolution Electron ◽  
Theoretical Predictions

ABSTRACTHigh resolution electron microscopy has been used to study the core structure of a/2[101] and a/3<112> dislocations in Ni3Al deformed in the range of increasing strength with temperature. a/3<112> coupled SISFs were found to lie on (111) and their structure agreed well with theoretical predictions. a/2[101] superpartials were always dissociated on (111) or (111) planes while the APB plane was found to be (010). Computer simulation of dislocation core structures were found to agree well with the observed dissociations. The APB width was found to increase significantly with increasing deformation temperature near the peak yield strength temperature.

scholarly journals Vitrification of Y zeolite and its effects on HREM images

1986 ◽  
Vol 44 ◽  
pp. 774-775
Author(s):  
R. Csencsits
Keyword(s):  
Electron Microscopy ◽  
Computer Simulation ◽  
Electron Microscope ◽  
High Resolution ◽  
High Resolution Electron Microscopy ◽  
Systematic Investigation ◽  
Y Zeolite ◽  
Y Zeolites ◽  
Transmission Electron ◽  
Resolution Electron

High resolution electron microscopy (HREM) is a valuable technique for studying catalytic zeolite systems because it gives direct information about the structure and defects present in the structure. The difficulty with doing an HREM study on zeolites is that they become amorphous under electron irradiation. This work is a systematic investigation of the damage of Y zeolites in the transmission electron microscope (TEM); the goals of this study are to determine the mechanism for electron damage and to access the effects of damage in Y zeolites on their HREM images using computer simulation.

Mixed partial dislocation core structure in GaN by high resolution electron microscopy

2006 ◽  
Vol 203 (9) ◽  
pp. 2156-2160 ◽  
Author(s):  
J. Kioseoglou ◽  
G. P. Dimitrakopulos ◽  
Ph. Komninou ◽  
Th. Kehagias ◽  
Th. Karakostas
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Partial Dislocation ◽  
Dislocation Core ◽  
High Resolution Electron Microscopy ◽  
Core Structure ◽  
Resolution Electron ◽  
Dislocation Core Structure

Nanoscale Measurement of Stress and Strain by Quantitative High-Resolution Electron Microscopy

2005 ◽  
Vol 482 ◽  
pp. 39-44 ◽  
Author(s):  
Martin J. Hÿtch ◽  
Jean-Luc Putaux ◽  
Jean-Michel Pénisson
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Spatial Resolution ◽  
Strain Tensor ◽  
Dislocation Core ◽  
High Resolution Electron Microscopy ◽  
Stress And Strain ◽  
Fourier Space ◽  
Resolution Electron ◽  
Anisotropic Elastic

The geometric phase technique (GPA) for measuring the distortion of crystalline lattices from high-resolution electron microscopy (HRTEM) images will be described. The method is based on the calculation of the “local” Fourier components of the HRTEM image by filtering in Fourier space. The method will be illustrated with a study of an edge dislocation in silicon where displacements have been measured to an accuracy of 3 pm at nanometre resolution as compared with anisotropic elastic theory calculations. The different components of the strain tensor will be mapped out in the vicinity of the dislocation core and compared with theory. The accuracy is of the order of 0.5% for strain and 0.1° for rigid-body rotations. Using bulk elastic constants for silicon, the stress field is determined to 0.5 GPa at nanometre spatial resolution. Accuracy and the spatial resolution of the technique will be discussed.

L12- and L10-like cation-ordered structures in ZrO2–Y2O3 ceramics

2001 ◽  
Vol 16 (6) ◽  
pp. 1806-1813 ◽  
Author(s):  
J. C. Rao ◽  
Y. Zhou ◽  
D. X. Li
Keyword(s):  
Electron Microscopy ◽  
Computer Simulation ◽  
High Resolution ◽  
Annealing Temperature ◽  
High Resolution Electron Microscopy ◽  
Energy Dispersive ◽  
Ordered Structures ◽  
X Ray ◽  
Resolution Electron

Y0.25Zr0.75O2−x and Y0.5Zr0.5O2−y phases, with L12- and L10- like cation-ordered structures, respectively, have been found in ZrO2–Y2O3 ceramics in both the sintered and annealed states. High-resolution electron microscopy, energy-dispersive x-ray spectroscopy and computer simulation have been used to reveal the presence of the phases. The formation of Y0.25Zr0.75O2−x and Y0.5Zr0.5O2−y phases was initiated during the sintering procedure and developed with the increase in annealing temperature and time. Segregation of yttrium, which was prevalent in different regions even within one grain, induced the formation of Y0.25Zr0.75O2−x and Y0.5Zr0.5O2−y phases.

HREm Study of Al-Si Interfaces

1990 ◽  
Vol 209 ◽  
Author(s):  
Mohammad Shamsuzzoha ◽  
Pierre A. Deymier ◽  
David J. Smith
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Structural Unit ◽  
High Resolution Electron Microscopy ◽  
Eutectic Liquid ◽  
The Core ◽  
Resolution Electron ◽  
Interfacial Dislocations

ABSTRACTInterfaces between aluminum and silicon in samples prepared by solidification of an Al-Si eutectic liquid have been studied by high-resolution electron microscopy. The Al and Si grains have a common [110] axis with a misorientation between grains of 70.5°, thus aligning the (lll)si plane with the (111)ALplane. In general, theinterfaces have a complex structurewith numerous interfacial dislocations and considerable facetting. The core structurescan be characterized in terms of structural unit models. The nature of the facetting has also been investigated, in particular one facet which lies approximately along the (111)AL, and (l15)si planes and another which lies approximately along the (110)AL and (l14)si planes.

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