Effect of Carbon Impurity Content on Microstructural Evolution in Neutron-Irradiated Alpha Iron: Cluster Dynamics Modeling

2013 ◽  
Vol 1535 ◽  
Author(s):  
Yosuke Abe ◽  
Tomohito Tsuru ◽  
Shiro Jitsukawa
Keyword(s):  
Impurity Content ◽  
Maximum Size ◽  
Reaction Rates ◽  
Dynamics Modeling ◽  
Iron Cluster ◽  
Carbon Impurity ◽  
Alpha Iron ◽  
Impurity Atoms ◽  
Trapping Effect ◽  
C Complex

ABSTRACTCluster dynamics (CD) modeling has been used to estimate the long-term evolution of point defect (PD) clusters. However, previous studies have often simplified the governing equations by assuming the maximum size of mobile self-interstitial atom (SIA) clusters and by ignoring the one-dimensional (1D) reaction kinetics of SIA loops. They have also conducted parameter fittings, such as the clustered fraction and the maximum size of clusters produced by collision cascade, to reproduce experimental data. In this study, in addition to modeling the 1D motion of SIA loops in the framework of the production bias model (PBM), reaction rates associated with carbon impurity atoms present in alpha iron were formulated to consider the trapping effect of one-dimensionally migrating SIA loops by a vacancy-carbon (V-C) complex that was shown to have strong bindings with SIA loops by previous atomistic simulations. Calculations results for neutron-irradiated alpha iron showed that the developed CD model can successfully reproduce the saturation trend of the number density of immobile SIA loops in contrast to the prediction using a model without the trapping effect.

scholarly journals The di‐interstitial in silicon: Electronic properties and interactions with oxygen and carbon impurity atoms

2017 ◽  
Vol 214 (7) ◽  
pp. 1700261 ◽  
Author(s):  
Vasilii E. Gusakov ◽  
Stanislau B. Lastovskii ◽  
Leonid I. Murin ◽  
Ekaterina A. Tolkacheva ◽  
Lyudmila I. Khirunenko ◽  
...  
Keyword(s):  
Electronic Properties ◽  
Carbon Impurity ◽  
Impurity Atoms

Kinetics and Fluid Dynamics for Oil Residue Hydroconversion in Commercial Software

2007 ◽  
Vol 5 (1) ◽  
Author(s):  
T S Yamada ◽  
R Guirardello
Keyword(s):  
Fluid Dynamics ◽  
Computational Simulation ◽  
Reaction Rates ◽  
Ideal Gas ◽  
Multiphase System ◽  
Dynamics Modeling ◽  
Pseudo First Order Reaction ◽  
Two Fluids ◽  
Oil Residue ◽  
Parallel Reactions

The current work is a computational simulation, with the geometry of the Parr reactor series 4581, of a multiphase system with two fluids (hydrocarbon and hydrogen) and two domains (tank and impeller) for the kinetics of residue catalytic hydrocracking. The fluid dynamics modeling is based on the SPH process and the fundamental equations of mass balance and momentum quantities in an isothermal system. The turbulence phenomena are considered through the k-? model for the hydrocarbon and ``disperse phase zero equation" for the hydrogen. The chemical reactions are modeled by the means of a reactional net based on the pseudo components concept, with their loads and products separated according to the commercial cuts, schematized with six parallel reactions, three thermal and three catalytic, with pseudo-first order reaction rates. The domains are composed of hydrocarbon as a general fluid (a mixture of pseudo components + catalyst = ``slurry phase") and the hydrogen as an ideal gas.

Ab Initio Modelling of Interaction of the Edge Dislocation with Oxygen and Carbon Impurity Atoms in Silicon

2017 ◽  
Vol 9 (4) ◽  
pp. 04025-1-04025-4 ◽  
Author(s):  
T. V. Gorkavenko ◽  
◽  
I. V. Plyushchay ◽  
O. I. Plyushchay ◽  
V. A. Makara ◽  
...  
Keyword(s):  
Ab Initio ◽  
Edge Dislocation ◽  
Carbon Impurity ◽  
Impurity Atoms

LOW-TEMPERATURE RECOVERY OF DEFORMED ALUMINUM

1964 ◽  
Vol 42 (10) ◽  
pp. 1890-1901 ◽  
Author(s):  
M. L. Swanson
Keyword(s):  
Low Temperature ◽  
Impurity Content ◽  
Stage I ◽  
Stage Ii ◽  
Recovery Stage ◽  
Degree Of Deformation ◽  
Resistivity Measurements ◽  
Impurity Atoms ◽  
Interstitial Defects ◽  
Dislocation Pinning

The isochronal recovery of deformed polycrystalline Al was measured from 4 to 300 °K by means of residual electrical resistivity measurements. A well-defined recovery stage was observed between 60 and 100 °K (stage IIA); it has also been observed after neutron irradiation, but not after electron irradiation (Sosin 1963). This stage was enhanced by increasing the deformation or introducing quenched-in vacancies, and was suppressed by impurity atoms. These results can be explained by di-interstitial migration. The recovery below 60 °K (stage I) amounted to approximately 5%, and was independent of impurity content or degree of deformation. Both stage I and stage IIA recovery were greatly increased by a prior deformation and low-temperature anneal. A similar increase was observed for Au. This enhancement was attributed to a change in deformation mechanism because of dislocation pinning, which resulted in the formation of a preponderance of interstitial defects.

Molecular Dynamics Modeling of Growth, Micro-Structure and Stresses in Sputter-Deposited Films with Impurity Atom Incorporation

1992 ◽  
Vol 280 ◽  
Author(s):  
C. C. Fang ◽  
F. Jones ◽  
V. Prasad
Keyword(s):  
Thin Films ◽  
Molecular Dynamics ◽  
Ion Bombardment ◽  
Film Structure ◽  
Dynamics Modeling ◽  
Impurity Atoms ◽  
Argon Ion Bombardment ◽  
Sputter Deposited ◽  
Background Gas ◽  
Argon Ion

ABSTRACTThe structure and intrinsic stresses of sputter-deposited thin films are studied via a two-dimensional molecular dynamics (MD) model. Two body potentials are used to represent the interaction between film atoms, substrate atoms, ions and argon molecules. First, a nearly perfect substrate having zero stress is constructed using constant temperature and constant pressure algorithms. Then the film is deposited with and without in-situ argon ion bombardment and with and without an argon background gas; a source of impurities. The adatom energy is varied in order to investigate its influence on the film structure. During the simulation the film is allowed to expand and contract depending on the intrinsic stresses. The models demonstrate, for the first time, that the transition from large tensile to large compressive stresses in sputter deposited thin films is caused by the incorporation of tightly packed argon impurity atoms, achieved only at sufficiently high levels of argon ion bombardment and nickel adatom energies.

Experimental studies of the link between production and penetration of impurity atoms into the plasma edge and the central impurity content in TEXTOR-94

1997 ◽  
Vol 241-243 ◽  
pp. 793-798 ◽  
Author(s):  
B. Unterberg ◽  
H. Knauf ◽  
P. Lindner ◽  
V. Philipps ◽  
A. Pospieszczyk ◽  
...  
Keyword(s):  
Experimental Studies ◽  
Impurity Content ◽  
Plasma Edge ◽  
Impurity Atoms
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