Structural Relaxation by Precipitation in Al-Li I. Growth Kinetics of Precipitates

1991 ◽  
Vol 229 ◽  
Author(s):  
R. Kamel ◽  
N. K. Gobran ◽  
M. M. Danial
Keyword(s):  
Growth Kinetics ◽  
Structural Relaxation ◽  
Electrical Resistance ◽  
Physical Property ◽  
Diffusional Growth ◽  
Solvus Line ◽  
Structure Sensitive ◽  
Δ Phase ◽  
Two Phases ◽  
Kinetics Of

AbstractChanges in electrical resistance measured by the four probe method was adopted as a structure sensitive physical property used to trace changes in the atomic microstructure below and above the δ'-solvus line in the Al-Li binary alloys. The kinetics of the growth and dissolution of δ' phase (Al3Li) and the formation of δ phase (AlLi), below and above δ'-solvus line, during the coarsening process were studied by isochronal and isothermal investigations. The diffusional growth of δ'-phase, below the δ'-solvus line, was found to be activated by 0.24 eV. Interpretation of the results showed that this energy involved two events during the coarsening process. The first event seemed to be a breakdown of the bonding between the vacancy-Lithium pair and the second event involved the transport of Li atoms to Al-particles to coarsen δ'; (Al3Li) particles. Furthermore, the study of the temperature dependence of electrical resistance of the stable phases δ' and δ of Al-Li alloys was found to be accompanied by difference in the temperature coefficient of the electrical resistance and was attributed to the change in structure of the two phases considered.

Diffusional Growth Kinetics of Boride Layers on Iron-Chromium Alloys

2008 ◽  
pp. 181-188 ◽  
Author(s):  
V.I. Dybkov ◽  
L.V. Goncharuk ◽  
V.G. Khoruzha ◽  
K.A. Meleshevich ◽  
A.V. Samelyuk ◽  
...  
Keyword(s):  
Growth Kinetics ◽  
Diffusional Growth ◽  
Chromium Alloys ◽  
Kinetics Of ◽  
Iron Chromium

Precipitation of Oxygen and Mechanism of Stacking Fault Formation in Czochralski Silicon Bulk Crystals

1982 ◽  
Vol 14 ◽  
Author(s):  
Kazumi Wada ◽  
Naohisa Inoue ◽  
Jiro Osaka
Keyword(s):  
Growth Model ◽  
Growth Kinetics ◽  
Stacking Faults ◽  
Diffusional Growth ◽  
Czochralski Silicon ◽  
Self Diffusion ◽  
Diffusion Limited ◽  
Silicon Bulk ◽  
Precipitate Growth ◽  
Kinetics Of

ABSTRACTThis paper describes recent progress on nucleation and growth of oxide precipitates and stacking faults in Czochralski silicon. Conclusions on the growth kinetics of oxide precipitates are drawn from the experiments and analysis of growth kinetics of two-dimensional precipitates: The experimentally obtained growth kinetics, three-quarter power law is theoretically derived and the precipitate growth is demonstrated to be diffusion-limited by oxygen interstitials. The formation mechanism of stacking faults is the Bardeen-Herring mechanism. Based on diffusional growth model, the growth kinetics of stacking faults are analyzed, assuming a coexistence of self-interstitial supersaturation and vacancy undersaturation. It is found that the growth is driven by vacancies in undersaturation. Vacancy component of self-diffusion has been determined and found to be predominant at low temperature. The possibility of growth model proposed for increase of oxide precipitate density during annealing has been excluded. Both processes, homogeneous and heterogeneous nucleation, have been taking place during annealing.

Kinetics of structural relaxation of bulk and ribbon Pd40Cu30Ni10P20 glasses determined from electrical resistance measurements

2007 ◽  
Vol 49 (8) ◽  
pp. 1411-1416 ◽  
Author(s):  
S. V. Khonik ◽  
V. V. Sviridov ◽  
N. P. Kobelev ◽  
M. Yu. Yazvitskiĭ ◽  
V. A. Khonik
Keyword(s):  
Structural Relaxation ◽  
Electrical Resistance ◽  
Electrical Resistance Measurements ◽  
Kinetics Of

Analysis of Morphology and Growth Kinetics of Zn-Mn and Zn-0.2wt.%Al-Mn Hot-Dip Galvanizing Coatings

2011 ◽  
Vol 291-294 ◽  
pp. 233-236
Author(s):  
Jian Hua Wang ◽  
Zi Shi Wu ◽  
Xu Ping Su ◽  
Chang Jun Wu ◽  
Ya Liu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Growth Kinetics ◽  
Immersion Time ◽  
Intermetallic Phase ◽  
Phase Changes ◽  
Zinc Bath ◽  
Phase Layer ◽  
Δ Phase ◽  
Kinetics Of ◽  
Scanning Electron

The influence of manganese in Zn-Mn and Zn-0.2wt.%Al-Mn bath on the morphology and growth kinetics of the galvanizing coatings has been studied using scanning electron microscopy equipped with energy dispersive spectroscopy. When galvanized in zinc bath, the coating consists mainly h and ζphase. When manganese is added in zinc bath, the morphology of ζ phase changes from fragmental to compact. Manganese favors the formation of the δ phase and inhibits the growth of the ζ phase.When galvanized in Zn-0.2wt.%Al bath, the coating consists only δ and h phase. With the addition of manganese in Zn-0.2wt.%Al bath, the morphology of δ phase changes from fragmental to compact The thickness of the Fe-Zn intermetallic phase layer in coatings decreases obviously when manganese is added into zinc and Zn-0.2wt.%Al bath, and the thickness increases slowly with the increase of immersion time.

Diffusional Growth Kinetics of Boride Layers on Iron-Chromium Alloys

2008 ◽  
Vol 138 ◽  
pp. 181-188 ◽  
Author(s):  
Vasil I. Dybkov ◽  
L.V. Goncharuk ◽  
V.G. Khoruzha ◽  
K.A. Meleshevich ◽  
A.V. Samelyuk ◽  
...  
Keyword(s):  
Experimental Data ◽  
Growth Kinetics ◽  
Reaction Times ◽  
Layer Growth ◽  
Diffusional Growth ◽  
Chromium Alloys ◽  
Layer Growth Rate ◽  
Linear Differential ◽  
Kinetics Of ◽  
Iron Chromium

Two boride layers were found to form at the interface of iiron-chromiium alllloys (10 and 25% Cr) or an industrial 13% Cr steel and boron at 850-950 oC and reaction times in the range 1-12 h. In the case of a Fe-10% Cr alloy and the steel, the layers are based on the FeB and Fe2B compounds. With a Fe-25% Cr alloy, the constituent phases are FeB and CrB for the outer layer and Fe2B and Cr2B for the inner layer. Both layers are characterized by a pronounced texture. Diffusional growth kinetics of boride layers are close to parabolic and can alternatively be described by a system of two non-linear differential equations, producing a good fit to the experimental data. The temperature dependence of the layer growth-rate constants obeys a relation of the Arrhenius type.

Diffusional Growth Kinetics of Boride Layers at the 13% Cr Steel Interface with Amorphous Boron

2007 ◽  
Vol 263 ◽  
pp. 183-188 ◽  
Author(s):  
Vasil I. Dybkov
Keyword(s):  
Experimental Data ◽  
Differential Equations ◽  
Growth Kinetics ◽  
Reaction Times ◽  
Average Content ◽  
Amorphous Boron ◽  
Diffusional Growth ◽  
Fe2b Phase ◽  
Linear Differential ◽  
Kinetics Of

Two borides FeB and Fe2B were found to form as separate layers at the interface between a 13% Cr steel and boron at 850-950 oC and reaction times up to 12 h. The chromium distribution within the boride layers is rather irregular. Its average content is 8 at. % in the FeB layer and 9 at. % in the Fe2B layer. Both layers are characterized by a pronounced texture. The strongest reflections are {002} and {020} for the orthorhombic FeB phase and {002} for the tetragonal Fe2B phase. Diffusional growth kinetics of boride layers are close to parabolic and can alternatively be described by a system of two non-linear differential equations, producing a good fit to the experimental data.

The Ordered Phase Formation in Ti-Al-Ga Alloys

1970 ◽  
Vol 28 ◽  
pp. 440-441
Author(s):  
Shiro Fujishiro ◽  
Harold L. Gegel
Keyword(s):  
Thermal Stability ◽  
High Temperature ◽  
Titanium Alloys ◽  
Growth Kinetics ◽  
Stoichiometric Composition ◽  
Good Potential ◽  
Alpha Titanium ◽  
Cold Rolled ◽  
Kinetics Of ◽  
Thermal Stability Of

Ordered-alpha titanium alloys having a DO19 type structure have good potential for high temperature (600°C) applications, due to the thermal stability of the ordered phase and the inherent resistance to recrystallization of these alloys. Five different Ti-Al-Ga alloys consisting of equal atomic percents of aluminum and gallium solute additions up to the stoichiometric composition, Ti3(Al, Ga), were used to study the growth kinetics of the ordered phase and the nature of its interface.The alloys were homogenized in the beta region in a vacuum of about 5×10-7 torr, furnace cooled; reheated in air to 50°C below the alpha transus for hot working. The alloys were subsequently acid cleaned, annealed in vacuo, and cold rolled to about. 050 inch prior to additional homogenization

Growth Kinetics of Quantum Size ZnO Particles

1998 ◽  
Vol 536 ◽  
Author(s):  
E. M. Wong ◽  
J. E. Bonevich ◽  
P. C. Searson
Keyword(s):  
Growth Kinetics ◽  
Ostwald Ripening ◽  
Chemical Potential ◽  
Colloidal Suspensions ◽  
Green Emission ◽  
Blue Shift ◽  
Constant Current ◽  
Mass Model ◽  
Zno Particles ◽  
Kinetics Of

AbstractColloidal chemistry techniques were used to synthesize ZnO particles in the nanometer size regime. The particle aging kinetics were determined by monitoring the optical band edge absorption and using the effective mass model to approximate the particle size as a function of time. We show that the growth kinetics of the ZnO particles follow the Lifshitz, Slyozov, Wagner theory for Ostwald ripening. In this model, the higher curvature and hence chemical potential of smaller particles provides a driving force for dissolution. The larger particles continue to grow by diffusion limited transport of species dissolved in solution. Thin films were fabricated by constant current electrophoretic deposition (EPD) of the ZnO quantum particles from these colloidal suspensions. All the films exhibited a blue shift relative to the characteristic green emission associated with bulk ZnO. The optical characteristics of the particles in the colloidal suspensions were found to translate to the films.

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