High-resolution Transmission Electron Microscopy of dislocations in intermetallic compounds

1995 ◽  
Vol 53 ◽  
pp. 76-77
Author(s):  
M.J. Mills
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Intermetallic Compounds ◽  
Structural Information ◽  
Critical Role ◽  
Atomic Level ◽  
Low Energy ◽  
Transmission Electron ◽  
Line Defects

The fine structure of dislocations plays a critical role in determining the macroscopic mechanical behavior Intermetallic compounds. Many of the technologically important characteristics of these compounds, an example their strength at high temperatures, appear to be determined by intricate details of dislocation stucture at the atomic level. High resolution transmission electron microscopy (HREM) offers the etential to obtain structural information at this level by observing these line defects in an "end-on" configuration.Samples of HREM images of several important dislocation types in Ni3Al and TiAl are shown in Figures through 3. Each of these particular dislocation types (i.e. Burgers vectors and line directions) tend to be longly favored in these compounds, indicating that along these line directions the dislocations are likely have either low mobility or low energy.

Quantifying The Effects Of Amorphous Layers on Image Contrast Using Energy Filtered Transmission Electron Microscopy

1994 ◽  
Vol 354 ◽  
Author(s):  
C. B. Boothroyd ◽  
R. E. Dunin-borkowski ◽  
W. M. Stobbs ◽  
C. J. Humphreys
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Inelastic Scattering ◽  
Carbon Film ◽  
Absolute Intensity ◽  
Atomic Level ◽  
Intensity Scale ◽  
Transmission Electron ◽  
High Resolution Images

AbstractHigh resolution images of a block oxide, (Nb205)çi(W03)8, with and without a superposed carbon film are compared both energy filtered and including the inelastic scattering. The differences between the images are quantified on an absolute intensity scale and possible origins of the differences in atomic level contrast are assessed using multislice simulations.

scholarly journals Recent Advances in Electron Tomography: TEM and HAADF-STEM Tomography for Materials Science and Semiconductor Applications

2005 ◽  
Vol 11 (5) ◽  
pp. 378-400 ◽  
Author(s):  
Christian Kübel ◽  
Andreas Voigt ◽  
Remco Schoenmakers ◽  
Max Otten ◽  
David Su ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Structural Information ◽  
Electron Tomography ◽  
Semiconductor Devices ◽  
Three Dimensional ◽  
Crystalline Materials ◽  
Transmission Electron ◽  
Stem Tomography

Electron tomography is a well-established technique for three-dimensional structure determination of (almost) amorphous specimens in life sciences applications. With the recent advances in nanotechnology and the semiconductor industry, there is also an increasing need for high-resolution three-dimensional (3D) structural information in physical sciences. In this article, we evaluate the capabilities and limitations of transmission electron microscopy (TEM) and high-angle-annular-dark-field scanning transmission electron microscopy (HAADF-STEM) tomography for the 3D structural characterization of partially crystalline to highly crystalline materials. Our analysis of catalysts, a hydrogen storage material, and different semiconductor devices shows that features with a diameter as small as 1–2 nm can be resolved in three dimensions by electron tomography. For partially crystalline materials with small single crystalline domains, bright-field TEM tomography provides reliable 3D structural information. HAADF-STEM tomography is more versatile and can also be used for high-resolution 3D imaging of highly crystalline materials such as semiconductor devices.

High-resolution transmission electron microscopy: A structural and chemical probe of semiconductor systems

1987 ◽  
Vol 45 ◽  
pp. 332-333
Author(s):  
A. Ourmazd
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Structural Information ◽  
Image Interpretation ◽  
Lattice Image ◽  
Semiconductor Interfaces ◽  
Transmission Electron ◽  
Lattice Images ◽  
The Individual

High Resolution Transmission Electron Microscopy (HRTEM) is now a powerful probe for the structural analysis of semiconductor systems. Lattice images can be obtained in a number of orientations, in at least three of which the individual atomic columns can be resolved. However, there exits an important class of problems, whose resolution requires chemical as well as structural information. The identification of individual atomic columns in compound semiconductors, and the atomic configuration of semiconductor/semiconductor interfaces are two important examples.In general, most reflection used to form a lattice image are not particularly sensitive to chemical changes in the sample. The information content of a typical lattice image is therefore strongly dominated by structural details. On the other hand, reflections such as the (200), which are normally forbidden in the diamond structure, come about in the zinc-blende system because of the chemical differences between the occupants of the two sublattices, and are thus highly chemically sensitive. In the “kinematical” thickness region, where simple image interpretation is possible, such reflections are relatively weak and their contribution to the lattice image is dominated by the stronger and chemically insensitive, allowed reflections.

Microstructure and Mechanical Properties of SiC/zirconia-toughened Mullite Nanocomposites Prepared from Mixtures of Mullite Gel, 2Y-TZP, and SiC Nanopowders

2002 ◽  
Vol 17 (5) ◽  
pp. 1024-1029 ◽  
Author(s):  
X. H. Jin ◽  
L. Gao ◽  
L. H. Gui ◽  
J. K. Guo
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Grain Boundaries ◽  
Low Energy ◽  
Liquid Interfaces ◽  
Sic Nanoparticles ◽  
Transmission Electron ◽  
The Matrix

SiC/ZTM (zirconia-toughened mullite) nanocomposites were prepared by hot pressing mixtures of mullite gel, 2Y-TZP, and SiC nanopowders. The intimate mixing of Al2O3 and SiO2 components in the starting powder prevented intermediate ZrSiO4 phase formation during sintering. Addition of nano-sized SiC significantly retarded the matrix grain growth, making the microstructure much finer and more uniform. Transmission electron microscopy and high-resolution transmission electron microscopy revealed that many SiC nanoparticles were found in mullite and ZrO2 grains, and low-energy grain boundaries and mullite–liquid interfaces parallel to the {110} planes of rodlike mullite grains were formed. It is deduced that the formation of rodlike mullite grains is the result of the preferential development of these low-energy grain boundaries and mullite–liquid interfaces. The mechanical properties of the SiC/ZTM nanocomposite showed significant improvement over those of ZTM, and further enhancement in the mechanical properties was achieved by combinative strengthening with nano- and micro-sized SiC.

In Situ High-Resolution Transmission Electron Microscopy in the Study of Nanomaterials and Properties

MRS Bulletin ◽  
2008 ◽  
Vol 33 (2) ◽  
pp. 115-121 ◽  
Author(s):  
James M. Howe ◽  
Hirotaro Mori ◽  
Zhong Lin Wang
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Transport Properties ◽  
Atomic Level ◽  
Transmission Electron ◽  
Interphase Boundaries ◽  
Future Potential

AbstractThis article introduces the use of in situ high-resolution transmission electron microscopy (HRTEM) techniques for the study and development of nanomaterials and their properties. Specifically, it shows how in situ HRTEM (and TEM) can be used to understand diverse phenomena at the nanoscale, such as the behavior of alloy phase formation in isolated nanometer-sized particles, the mechanical and transport properties of carbon nanotubes and nanowires, and the dynamic behavior of interphase boundaries at the atomic level. Current limitations and future potential advances in in situ HRTEM of nanomaterials are also discussed.

A High Resolution Study of G.P. Zones in Aluminum - 4.2 at % Silver

1982 ◽  
Vol 40 ◽  
pp. 722-723 ◽  
Author(s):  
R. Gronsky
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Computer Simulations ◽  
Structural Characteristics ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Resolution Study

The phenomenon of clustering in Al-Ag alloys has been extensively studied since the early work of Guinierl, wherein the pre-precipitation state was characterized as an assembly of spherical, ordered, silver-rich G.P. zones. Subsequent x-ray and TEM investigations yielded results in general agreement with this model. However, serious discrepancies were later revealed by the detailed x-ray diffraction - based computer simulations of Gragg and Cohen, i.e., the silver-rich clusters were instead octahedral in shape and fully disordered, atleast below 170°C. The object of the present investigation is to examine directly the structural characteristics of G.P. zones in Al-Ag by high resolution transmission electron microscopy.

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