Characterization of neutron irradiation damage in zirconium alloys—an international “round-robin” experiment

1978 ◽  
Vol 36 (1) ◽  
pp. 366-367
Author(s):  
D.O. Northwood ◽  
R.W. Gilbert ◽  
P.M. Kelly ◽  
P.K. Madden ◽  
D. Faulkner ◽  
...  
Keyword(s):  
Zirconium Alloys ◽  
Round Robin ◽  
Irradiation Damage ◽  
Exact Nature ◽  
Dislocation Loops ◽  
The Past ◽  
Irradiation Growth ◽  
Transmission Electron ◽  
International Round

Over the past few years there has been disagreement between laboratories on the exact nature of the damage in irradiated zirconium alloys. The main disagreement has centred on whether or not dislocation loops with c-component Burgers' vectors are formed during the irradiation. Since the presence of c-component loops was required in one of the current theories of irradiation growth and is considered in many other models, it was desirable to clear up this point and others relating to the nature of the damage such as loop size, loop concentration and the nature of the loop population, i.e. vacancy or interstitial. To this end a ‘round-robin’ series of transmission electron microscopy (TEM) examinations of neutron irradiated zirconium alloys was organized and the results are reported herein.The participants in the ‘round-robin’ included laboratories who had previously claimed to have seen evidence for c-component damage. The materials examined included zirconium and Zircaloy-2 irradiated at temperatures from 250-400°C, Table 1, the materials irradiated at 400°C providing samples with dislocation loops large enough to determine the interstitial/vacancy nature by inside/outside contrast techniques.

Characterization of neutron irradiation damage in zirconium alloys — an international “round-robin” experiment

1979 ◽  
Vol 79 (2) ◽  
pp. 379-394 ◽  
Author(s):  
D.O. Northwood ◽  
R.W Gilbert ◽  
L.E. Bahen ◽  
P.M. Kelly ◽  
R.G. Blake ◽  
...  
Keyword(s):  
Neutron Irradiation ◽  
Zirconium Alloys ◽  
Round Robin ◽  
Irradiation Damage ◽  
International Round

scholarly journals Two-dimensional vacancy platelets as precursors for basal dislocation loops in hexagonal zirconium

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Si-Mian Liu ◽  
Irene J. Beyerlein ◽  
Wei-Zhong Han
Keyword(s):  
Zirconium Alloys ◽  
Crystal Defects ◽  
Nuclear Industry ◽  
Two Dimensional ◽  
Dislocation Loops ◽  
Irradiation Growth ◽  
Transmission Electron ◽  
Long Time ◽  
Basal Dislocation ◽  
Shape Changes

AbstractZirconium alloys are widely used structural materials of choice in the nuclear industry due to their exceptional radiation and corrosion resistance. However long-time exposure to irradiation eventually results in undesirable shape changes, irradiation growth, that limit the service life of the component. Crystal defects called <c> loops, routinely seen no smaller than 13 nm in diameter, are the source of the problem. How they form remains a matter of debate. Here, using transmission electron microscopy, we reveal the existence of a novel defect, nanoscale triangle-shaped vacancy plates. Energy considerations suggest that the collapse of the atomically thick triangle-shaped vacancy platelets can directly produce <c> dislocation loops. This mechanism agrees with experiment and implies a characteristic incubation period for the formation of <c> dislocation loops in zirconium alloys.

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

Structure Determination of Clusters Formed in Ultra-Low Energy High-Dose Implanted Silicon

2005 ◽  
Vol 108-109 ◽  
pp. 303-308 ◽  
Author(s):  
N. Cherkashin ◽  
Martin J. Hÿtch ◽  
Fuccio Cristiano ◽  
A. Claverie
Keyword(s):  
Electron Microscopy ◽  
Geometric Phase ◽  
Low Energy ◽  
High Dose ◽  
Dislocation Loops ◽  
Weak Beam ◽  
Transmission Electron ◽  
Geometric Phase Analysis

In this work, we present a detailed structural characterization of the defects formed after 0.5 keV B+ implantation into Si to a dose of 1x1015 ions/cm2 and annealed at 650°C and 750°C during different times up to 160 s. The clusters were characterized by making use of Weak Beam and High Resolution Transmission Electron Microscopy (HRTEM) imaging. They are found to be platelets of several nanometer size with (001) habit plane. Conventional TEM procedure based on defect contrast behavior was applied to determine the directions of their Burger’s vectors. Geometric Phase Analysis of HRTEM images was used to measure the displacement field around these objects and, thus, to unambiguously determine their Burger’s vectors. Finally five types of dislocation loops lying on (001) plane are marked out: with ] 001 [1/3 ≅ b and b ∝ [1 0 1], [-1 0 1], [0 1 1], [0 -1 1].

scholarly journals Physical Testing and Surface Morphology Studies of Stainless Steel Irradiated with Xe Ions

2021 ◽  
Vol 2083 (2) ◽  
pp. 022036
Author(s):  
Chaoliang Xu ◽  
Xiangbing Liu ◽  
Yuanfei Li ◽  
Wenqing Jia ◽  
Wangjie Qian ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Surface Morphology ◽  
Positron Annihilation ◽  
Irradiation Damage ◽  
Dislocation Loops ◽  
Vacancy Defects ◽  
Positron Annihilation Lifetime ◽  
Atomic Force ◽  
Transmission Electron ◽  
Volume Swelling

Abstract 6 MeV Xe ions were used to irradiate austenitic stainless steel at room temperature. Three displacement damage levels of 2,7 and 15 dpa were selected. Microstructure and surface morphology were characterized by transmission electron microscopy (TEM), positron annihilation lifetime spectroscopy (PLS) and atomic force microscope (AFM). PLS indicated that vacancy defects were introduced by ions irradiation. Vacancy clusters containing Xe will reduce the positron annihilation lifetime. High density of dislocation loops were observed by TEM. The dislocation loops size and density saturates after 7 dpa and the nature of dislocation loops can be deduced by its distribution. A surface step was detected by AFM measurements between irradiated region (uncovered) and unirradiated region (covered with nickel mesh). This indicate that the irradiation swelling phenomenon occur and swelling is closely related to irradiation damage. According to the step height, the volume swelling is about 1.7% and 4.2% after irradiated to 7 and 15 dpa.

Characterization of Si MBE Layers Doped in Situ by As Ion Beams

1987 ◽  
Vol 102 ◽  
Author(s):  
Max L. Swanson ◽  
N.R. Parikh ◽  
T.E. Jackman ◽  
D.C. Houghton ◽  
M.W. Denhoff
Keyword(s):  
Structural Damage ◽  
Electrical Activation ◽  
Dislocation Loops ◽  
Electrical Measurements ◽  
Implantation Energy ◽  
Mbe Growth ◽  
Transmission Electron ◽  
High Concentrations

ABSTRACTTo achieve high concentrations and electrical activation of As in Si without subsequent annealing, 500-3000 eV As + ions were implanted during MBE growth of Si at 450-840°C. The epitaxial layers were characterized by Rutherford backscattering/channeling, transmission electron microscopy, secondary ion mald spectroscopy, and electrical measurements. Samples containing 1.2×1020 As cm-3 grown at 700°C showed little damage, high As substitutionality and high electrical activation. However, similarly doped layers grown at 460°C showed lower As activation and varying amounts of structural damage. In one case, a band of damage near the Si substrate was observed which persisted even after rapid thermal annealing at 1120°C (10 s); the damage was characterized by a dechanneling step, non-substitutional As atoms and dislocation loops. A sample grown at 460°C with a high implantation energy (3 keV) was highly defected.

Nucleation and Growth of {113} Defects and {111} Dislocation Loops Insilicon-Implanted Selicon

1997 ◽  
Vol 469 ◽  
Author(s):  
G. Z. Pan ◽  
K. N. Tu
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Microstructural Characterization ◽  
Nucleation And Growth ◽  
Growth Behavior ◽  
Dislocation Loops ◽  
Cross Sectional ◽  
Plan View ◽  
Transmission Electron

ABSTRACTPlan-view and cross-sectional transmission electron microscopy have been used to study the microstructural characterization of the nucleation and growth behavior of {113} rodlike defects, as well as their correlation with {111} dislocation loops in silicon amorphized with 50 keV, 36×1014 Si/cm2, 8.0 mAand annealed by rapid thermal anneals at temperatures from 500 °C to 1100 °C for various times. We found that the nucleations of the {113} rodlike defects and {111} dislocation loops are two separate processes. At the beginning of anneals, excess interstitials accumulate and form circular interstitial clusters at the preamorphous/crystalline interface at as low as 600 °C for 1 s. Then these interstitial clusters grow along the <110> direction to form {113} rodlike defects. Later, while the {113} defects have begun to grow and/or dissolve into matrix, the {111} faulted Frank dislocation loops start to form. We also found that the initial interstitial clusters prefer to grow along the <110>directions inclined to the implantation surface.

scholarly journals Irradiation Hardening and Microstructure Characterization of Zr -1% Nb During Low Dose Neutron Irradiation

2021 ◽  
Vol 10 (2) ◽  
pp. 63-72
Author(s):  
Carolina Vazquez ◽  
Eugenia Zelaya ◽  
Ana Maria Fortis ◽  
Patricia B. Bozzano
Keyword(s):  
Neutron Irradiation ◽  
Low Dose ◽  
Zirconium Alloys ◽  
Life Time ◽  
Tensile Tests ◽  
Crystal Defects ◽  
Second Phase ◽  
Hydrogen Damage ◽  
Transmission Electron

Due to low neutron absorption cross section, high mechanical strength, high thermal conductivity and good corrosion resistance in water and steam, Zirconium alloys are widely used as fuel cladding material in nuclear reactors. During life-time of a reactor the microstructure of this alloy is affected due to, among other factors, radiation damage and hydrogen damage. In this work mechanical properties changes on neutron irradiated Zr-1wt.% Nb at low temperatures (< 100 °C) and low dose (3.5 ´ 1023 n m-2 (E > 1 MeV)) were correlated with hydrides and crystal defects evolution during irradiation. To achieve this propose, tensile tests of: 1) Non-hydrided and non-irradiated material, 2) Hydrided and non-irradiated material and 3) Hydrided and irradiated material were performed at 25 ºC and 300 ºC. Different phases, hydrides and second phase precipitates were characterized by transmission electron microscopy (TEM) techniques. For the hydrided and irradiated material, the ductility decreased sharply with respect to the hydrided and non-irradiated material, among other factors, due to the change in the microstructure produced mainly by neutron irradiation. Even if the presence of the hydride ζ (zeta) was observed, both in the irradiated and non-irradiated material, tensile tests showed that ζ-hydrides did not affect ductility, since hydrided samples are more ductile than non-hydrided samples.

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