Atomic structure of interface of intermetallic compound TiAl and nitride Ti2AIN using HREM and image processing

1991 ◽  
Vol 49 ◽  
pp. 570-571
Author(s):  
E. Sukedai ◽  
H. Mabuchi ◽  
H. Hashimoto ◽  
Y. Nakayama
Keyword(s):  
Mechanical Properties ◽  
Image Processing ◽  
Composite Material ◽  
Intermetallic Compound ◽  
Side Surface ◽  
High Resolution Electron Microscopy ◽  
Hexagonal Structure ◽  
Second Phase ◽  
Resolution Electron ◽  
Compound Tial

In order to improve the mechanical properties of an intermetal1ic compound TiAl, a composite material of TiAl involving a second phase Ti2AIN was prepared by a new combustion reaction method. It is found that Ti2AIN (hexagonal structure) is a rod shape as shown in Fig.1 and its side surface is almost parallel to the basal plane, and this composite material has distinguished strength at elevated temperature and considerable toughness at room temperature comparing with TiAl single phase material. Since the property of the interface of composite materials has strong influences to their mechanical properties, the structure of the interface of intermetallic compound and nitride on the areas corresponding to 2, 3 and 4 as shown in Fig.1 was investigated using high resolution electron microscopy and image processing.

Recent Applications of High Resolution Electron Microscopy to Crystalline Arrays of Virus Particles

1978 ◽  
Vol 36 (3) ◽  
pp. 470-482 ◽  
Author(s):  
R.W. Horne
Keyword(s):  
Electron Microscopy ◽  
Image Processing ◽  
Analytical Techniques ◽  
Staining Technique ◽  
High Resolution Electron Microscopy ◽  
Optical Diffraction ◽  
Full Potential ◽  
Virus Particles ◽  
Resolution Electron ◽  
Wide Range

The technique of surrounding virus particles with a neutralised electron dense stain was described at the Fourth International Congress on Electron Microscopy, Berlin 1958 (see Home & Brenner, 1960, p. 625). For many years the negative staining technique in one form or another, has been applied to a wide range of biological materials. However, the full potential of the method has only recently been explored following the development and applications of optical diffraction and computer image analytical techniques to electron micrographs (cf. De Hosier & Klug, 1968; Markham 1968; Crowther et al., 1970; Home & Markham, 1973; Klug & Berger, 1974; Crowther & Klug, 1975). These image processing procedures have allowed a more precise and quantitative approach to be made concerning the interpretation, measurement and reconstruction of repeating features in certain biological systems.

Digital image processing for high resolution electron microscopy

1988 ◽  
Vol 107 (2) ◽  
pp. 521-530 ◽  
Author(s):  
W. Coene ◽  
A. F. de Jong ◽  
D. van Dyck ◽  
G. van Tendeloo ◽  
J. van Landuyt
Keyword(s):  
Electron Microscopy ◽  
Image Processing ◽  
High Resolution ◽  
Digital Image Processing ◽  
Digital Image ◽  
High Resolution Electron Microscopy ◽  
Resolution Electron

Transmission electron microscopy observation of second-phase particles in β–Si3N4 grains

1999 ◽  
Vol 14 (7) ◽  
pp. 2959-2965 ◽  
Author(s):  
Naoto Hirosaki ◽  
Tomohiro Saito ◽  
Fumio Munakata ◽  
Yoshio Akimune ◽  
Yuichi Ikuhara
Keyword(s):  
Electron Microscopy ◽  
Silicon Nitride ◽  
Heat Treating ◽  
High Resolution Electron Microscopy ◽  
Second Phase ◽  
Transmission Electron ◽  
Resolution Electron ◽  
Second Phase Particles ◽  
Coarse Grains ◽  
Sintered Silicon

Silicon nitride was fabricated by adding Y2O3 and Nd2O3 as sintering additives, sintering for 8 h at 1900 °C, and heat treating for 4 h at 2200 °C to enhance grain growth. The microstructure was investigated by scanning electron microscopy, high-resolution electron microscopy, energy dispersive x-ray spectroscopy (EDS), and electron microdiffraction. This material had a duplex microstructure composed of many fine grains and a few coarse grains. In β–Si3N4 grains, second-phase particles with the composition of liquid phase, Y–Nd–Si–O or Y–Nd–Si–O–N, in the size of 10–30 nm were observed. EDS spectra and microdiffraction patterns revealed that those were amorphous or crystalline particles of Y–Nd–apatite, (Y,Nd)10Si6O24N2. These particles were presumably formed during cooling by the precipitation of Y–Nd–Si–O–N, which was trapped in the β–Si3N4 grains as solid solution or trapped liquid. The results suggest that attention should be paid to the trace amounts of trapped elements in β–Si3N4 grains in trying to improve the thermal conductivity of sintered silicon nitride.

Mechanical properties of hot isostatically pressed Si3N4 and Si3N4/SiC composites

1993 ◽  
Vol 8 (3) ◽  
pp. 626-634 ◽  
Author(s):  
O. Unal ◽  
J.J. Petrovic ◽  
T.E. Mitchell
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Fracture Toughness ◽  
High Hardness ◽  
High Resolution Electron Microscopy ◽  
Transmission Electron ◽  
Resolution Electron ◽  
Sic Whiskers ◽  
Sic Composites ◽  
Increasing Temperature

The mechanical properties of hot isostatically pressed monolithic Si3N4 and Si3N4−20 vol. % SiC composites have been studied by microindentation at temperatures up to 1400 °C. Indentation crack patterns and microstructures have been examined by optical microscopy, scanning electron microscopy, and transmission electron microscopy. It is shown that dense Si3N4 base materials can be synthesized by HIPing without densification aids. Both the monolithic Si3N4 and the Si3N4/SiC composites exhibit high hardness values which gradually decrease with increasing temperature. Both types of material show low fracture toughness values apparently because of strong interfacial bonding. On the other hand, the fracture toughness of the composite is about 40% higher than that of the monolithic material, due to the presence of the 20 vol. % SiC whiskers. A crack deflection/debonding mechanism is likely to be responsible for the higher toughness observed in the composite. High resolution electron microscopy shows that the grain boundaries in both samples contain a thin SiO2 layer.

Digital Image Processing in High Resolution Electron Microscopy

1975 ◽  
Vol 33 ◽  
pp. 12-13
Author(s):  
J. Frank
Keyword(s):  
Image Processing ◽  
High Resolution ◽  
Signal To Noise Ratio ◽  
A Priori ◽  
Image Interpretation ◽  
High Resolution Electron Microscopy ◽  
Input Image ◽  
Additional Information ◽  
Resolution Electron ◽  
Priori Information

Image processing can be considered as an attempt to aid image interpretation and to improve image quality by using additional information not contained in the image, or to make optimal use of redundant information contained in the image. Since high resolution electron micrographs contain a very high amount of noise from substrate, electron statistics and photographic grain, the separation of the signal from the noise part of the image is one of the most important problems. An operation that produces an output image with a higher signal-to-noise ratio than the input image may appear as witchcraft but is in fact feasible through clever use of a-priori information such as the knowledge of object and noise statistics.

Molecular imaging of Organo-Calcium salts by High Resolution Electron Microscopy and Image Processing

1990 ◽  
Vol 48 (1) ◽  
pp. 590-591
Author(s):  
G. Miller ◽  
J.R. Fryer ◽  
W. Kunath ◽  
K. Weiss
Keyword(s):  
Electron Microscopy ◽  
Image Processing ◽  
High Resolution ◽  
Low Dose ◽  
High Resolution Electron Microscopy ◽  
Unit Cell ◽  
Recording Device ◽  
Resolution Electron

Unfortunatly Wolfgang Kunath died January 1990High resolution electron microscopy and image processing are being used to determine the molecular packing within the crystal unit cell of the, organic-azo calcium salt. Due to the beam sensitive nature of the organic moiety which contains both aromatic and and aliphatic components, low dose techniques were used. This concisted of, searching the sample in the diffraction mode to find single crystals exibiting point like reflection to at least .2nm resolution, (fig. 1). Focusing and astigmatism correction was performed by moving the beam of the crystal (off axis). The beam was then moved on axis and a series of four, 10 e/A images taken, (fig. 2). Images were primarily recorded using an on line T.V. recording device. These images were then available for processing using the Semper image processing system. Two crystal orientations were found. Type 1 consisted of thin plate like crystals up to 5um diameter and generally 10nm to 20nm thick. Type 2 were thicker crystals with a 3.2nm lattice spacing. The power specrta of the first low dose images were calculated to asses the quality of the of the structural information present. For the type 1 crystal the power spectrum had to show at least second order reflections in two directions ( fig. 3 ). Type 2 crystals showed the 3.2nm reflection often down to the fith order. These crystals also showed parallel side bands corresponding to a d-spacing of about .8nm. With these results the unit cell was found to be tetragonal with a= .78nm b= 3.2nm c= .78nm. In accordance with the diffraction patterns exibited.

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