Effect of Prior-Deformation on the Stability of the Intermetallic Precipitate in Zircaloy-2

1994 ◽  
Vol 373 ◽  
Author(s):  
Peter Y Huang ◽  
R.B. Adamson
Keyword(s):  
Scanning Transmission Electron Microscopy ◽  
Cold Work ◽  
Mechanical Deformation ◽  
Black Dot ◽  
Irradiation Effects ◽  
Transmission Electron ◽  
Preferential Diffusion ◽  
Intermetallic Precipitates ◽  
Scanning Transmission ◽  
The Stability

AbstractBoth stress-relieved (SR) and recrystallized (RX) samples irradiated near 300°C tofluences between 1 and 9 x 1021 n/;cm2 (E>IMeV) were examined using analytical scanning transmission electron microscopy (STEM). The aim was to extend our knowledge of irradiation effects on microstructure by examining the effect of prior-cold-work on the dissolution of intermetallic precipitates in Zircaloy-2. Resulting from prior mechanical deformation and fast neutron irradiation, SR samples contain a high density of <a>-component, mixed <a+> line dislocations and “black dot” damage. On the other hand, RX samples contain mostly “black dot” damage. Pure <c>-dislocations are detected in the high fluence samples in RX materials. For identical irradiation conditions, different degrees of amorphization and dissolution are observed in RX and SR samples. Also, preferential diffusion of solute is observed to occur along <c>-dislocations. These results are discussed in terms of possible interactions between irradiation produced defects, precipitates and solutes.

Analytical STEM of Borosilicate Glasses Containing Molybdates.

2004 ◽  
Vol 824 ◽  
Author(s):  
Rick J. Short ◽  
Günter Möbus ◽  
Guang Yang ◽  
Russell J. Hand ◽  
Neil Hyatt ◽  
...  
Keyword(s):  
Scanning Transmission Electron Microscopy ◽  
Glass Structure ◽  
Borosilicate Glasses ◽  
Irradiation Effects ◽  
Base Glass ◽  
Transmission Electron ◽  
Simulated Waste ◽  
Scanning Transmission ◽  
Shape Mapping ◽  
Z Contrast

AbstractBorosilicate nuclear waste glasses with various amounts of simulated waste elements have been examined by analytical TEM. This preliminary Scanning Transmission Electron Microscopy (STEM) study evaluates the capability of EELS for mapping coordination parameters of the base glass structure, to apply EDX-mapping and HAADF Z-contrast mapping for the characterisation and shape-mapping of common precipitates in nuclear glasses, such as molybdates, and to study irradiation effects.

Diffusion, Segregation, and Recrystallization in High-Dose Ion-Implanted Si

1989 ◽  
Vol 147 ◽  
Author(s):  
S. J. Pennycook
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Scanning Transmission Electron Microscopy ◽  
High Dose ◽  
Growth Interface ◽  
Dopant Incorporation ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
The Stability ◽  
Z Contrast

AbstractUsing the new technique of Z-contrast scanning transmission electron microscopy (STEM), we have been able to study the segregation of Sb at an advancing SPE growth interface and the resulting interface breakdown. The first direct information is obtained on Sb diffusion in the amorphous phase, which is many orders of magnitude enhanced over tracer crystalline values. This controls both the dopant incorporation and the stability of the resulting supersaturated alloy. These results are compared to the behavior of the low melting point substitutional diffusers and the interstitial diffusers.

High-Voltage Scanning Electron Microscopy

1970 ◽  
Vol 28 ◽  
pp. 6-7
Author(s):  
J. M. Cowley
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Scanning Transmission Electron Microscopy ◽  
Wave Optics ◽  
Contrast Effects ◽  
Transmission Electron ◽  
Mode Of Operation ◽  
Scanning Transmission ◽  
Types Of Information ◽  
Voltage Scanning

The comparison of scanning transmission electron microscopy (STEM) with conventional transmission electron microscopy (CTEM) can best be made by means of the Reciprocity Theorem of wave optics. In Fig. 1 the intensity measured at a point A’ in the CTEM image due to emission from a point B’ in the electron source is equated to the intensity at a point of the detector, B, due to emission from a point A In the source In the STEM. On this basis it can be demonstrated that contrast effects In the two types of instrument will be similar. The reciprocity relationship can be carried further to include the Instrument design and experimental procedures required to obtain particular types of information. For any. mode of operation providing particular information with one type of microscope, the analagous type of operation giving the same information can be postulated for the other type of microscope. Then the choice between the two types of instrument depends on the practical convenience for obtaining the required Information.

Imaging and diffraction modes in Scanning Transmission Electron Microscopy

1986 ◽  
Vol 44 ◽  
pp. 684-687
Author(s):  
J. M. Cowley ◽  
R. Glaisher ◽  
J. A. Lin ◽  
H.-J. Ou
Keyword(s):  
Scanning Transmission Electron Microscopy ◽  
High Efficiency ◽  
Fiber Optic ◽  
Image Intensifier ◽  
Detector System ◽  
Detector Plane ◽  
Secondary Electrons ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Special Detector

Some of the most important applications of STEM depend on the variety of imaging and diffraction made possible by the versatility of the detector system and the serial nature, of the image acquisition. A special detector system, previously described, has been added to our STEM instrument to allow us to take full advantage of this versatility. In this, the diffraction pattern in the detector plane may be formed on either of two phosphor screens, one with P47 (very fast) phosphor and the other with P20 (high efficiency) phosphor. The light from the phosphor is conveyed through a fiber-optic rod to an image intensifier and TV system and may be photographed, recorded on videotape, or stored digitally on a frame store. The P47 screen has a hole through it to allow electrons to enter a Gatan EELS spectrometer. Recently a modified SEM detector has been added so that high resolution (10Å) imaging with secondary electrons may be used in conjunction with other modes.

Scanning Transmission Electron Microscopy of Polyethylene Crystals

1980 ◽  
Vol 38 ◽  
pp. 242-245
Author(s):  
F. Khoury ◽  
L. H. Bolz
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Crystallization Temperature ◽  
Scanning Transmission Electron Microscopy ◽  
Growth Habit ◽  
Lateral Growth ◽  
Scanning Transmission Electron ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Growth Habits

The lateral growth habits and non-planar conformations of polyethylene crystals grown from dilute solutions (<0.1% wt./vol.) are known to vary depending on the crystallization temperature.1-3 With the notable exception of a study by Keith2, most previous studies have been limited to crystals grown at <95°C. The trend in the change of the lateral growth habit of the crystals with increasing crystallization temperature (other factors remaining equal, i.e. polymer mol. wt. and concentration, solvent) is illustrated in Fig.l. The lateral growth faces in the lozenge shaped type of crystal (Fig.la) which is formed at lower temperatures are {110}. Crystals formed at higher temperatures exhibit 'truncated' profiles (Figs. lb,c) and are bound laterally by (110) and (200} growth faces. In addition, the shape of the latter crystals is all the more truncated (Fig.lc), and hence all the more elongated parallel to the b-axis, the higher the crystallization temperature.

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