scholarly journals Generalized Rate Theory for Void and Bubble Swelling and its Application to Plutonium Metal Alloys

2015 ◽  
Author(s):  
P. G. Allen ◽  
W. G. Wolfer
Keyword(s):  
Metal Alloys ◽  
Rate Theory ◽  
Plutonium Metal

Microscopy and Microanalysis of Plutonium Metal, Alloys and Oxides or the Problem With Pu

2000 ◽  
Vol 6 (S2) ◽  
pp. 932-933
Author(s):  
Rollin E. Lakis ◽  
Bradford G. Storey ◽  
Charles C. Davis
Keyword(s):  
Atomic Number ◽  
Atmospheric Pressure ◽  
Room Temperature ◽  
Pure Metal ◽  
University Of California ◽  
Metal Alloys ◽  
Naturally Occurring ◽  
The University ◽  
Crystalline Forms ◽  
Plutonium Metal

Plutonium (Pu), with an atomic number of 94, is the highest atomic number naturally occurring element on Earth. It is formed when naturally occurring Uranium 238 captures a neutron that can be created by spontaneous fission and alphaneutron reactions. The natural abundance of terrestrial Pu is very small; its concentration is about one part in 10 of the uranium present in naturally occurring uranium ores. The first man-made plutonium was produced at the University of California cyclotron and identified on February 23, 1941. Just a few months after the first Pu was produced it became clear how metallurgically complex this material is. Plutonium is known to have six allotropes (crystalline forms) at atmospheric pressure, between room temperature and 640°C, the melting point of the pure metal. This is the largest number of allotropes known for any element.

Specimen Preparation of Near Surface Ion Irradiated Samples

1985 ◽  
Vol 43 ◽  
pp. 170-171
Author(s):  
K. F. Russell ◽  
L. L. Horton
Keyword(s):  
Radiation Damage ◽  
Heavy Ions ◽  
Target Material ◽  
Metal Alloys ◽  
Specimen Surface ◽  
Specimen Preparation ◽  
Particle Accelerators ◽  
Near Surface ◽  
Graaff Accelerator ◽  
Van De Graaff

Beams of heavy ions from particle accelerators are used to produce radiation damage in metal alloys. The damaged layer extends several microns below the surface of the specimen with the maximum damage and depth dependent upon the energy of the ions, type of ions, and target material. Using 4 MeV heavy ions from a Van de Graaff accelerator causes peak damage approximately 1 μm below the specimen surface. To study this area, it is necessary to remove a thickness of approximately 1 μm of damaged metal from the surface (referred to as “sectioning“) and to electropolish this region to electron transparency from the unirradiated surface (referred to as “backthinning“). We have developed electropolishing techniques to obtain electron transparent regions at any depth below the surface of a standard TEM disk. These techniques may be applied wherever TEM information is needed at a specific subsurface position.

On the interpretation of dislocation-loop growth during in-situ high-voltage Electron Microscopy

1990 ◽  
Vol 48 (4) ◽  
pp. 532-533
Author(s):  
E. Holzäpfel ◽  
F. Phillipp ◽  
M. Wilkens
Keyword(s):  
Point Defect ◽  
Rate Equations ◽  
Rate Theory ◽  
Dislocation Loops ◽  
High Voltage Electron Microscopy ◽  
Vacancy Migration ◽  
Voltage Electron ◽  
Reaction Rate Theory ◽  
Defect Reactions

During in-situ radiation damage experiments aiming on the investigation of vacancy-migration properties interstitial-type dislocation loops are used as probes monitoring the development of the point defect concentrations. The temperature dependence of the loop-growth rate v is analyzed in terms of reaction-rate theory yielding information on the vacancy migration enthalpy. The relation between v and the point-defect production rate P provides a critical test of such a treatment since it is sensitive to the defect reactions which are dominant. If mutual recombination of vacancies and interstitials is the dominant reaction, vαP0.5 holds. If, however, annihilation of the defects at unsaturable sinks determines the concentrations, a linear relationship vαP is expected.Detailed studies in pure bcc-metals yielded vαPx with 0.7≾×≾1.0 showing that besides recombination of vacancies and interstitials annihilation at sinks plays an important role in the concentration development which has properly to be incorporated into the rate equations.

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