Modelling precipitate nucleation and growth with multiple precipitate species under isothermal conditions: Formulation and analysis

ABSTRACTIn this paper we first describe, in some detail, the nature of an exigentaccommodation- volume factor associated with oxygen (Oi) precipitation in Czochralski (CZ) Si. This factor is regarded as a causal or characteristic factor which influences many aspects of the SiO2 precipitate nucleation and growth phenomena. Employing this factor, we then describe the possible explanations of two outstanding features of Oi precipitation in CZ Si: the precipitation retardation/recovery phenomena and the nucleation incubation phenomena.

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High Resolution Moire Imaging of Small Precipitates

MRS Proceedings ◽

10.1557/proc-62-229 ◽

1985 ◽

Vol 62 ◽

Cited By ~ 6

Author(s):

W. Kesternich

Keyword(s):

High Resolution ◽

Lattice Mismatch ◽

Lattice Parameter ◽

Nucleation And Growth ◽

Austenitic Steels ◽

Defect Clusters ◽

The Matrix ◽

Electron Imaging ◽

Precipitate Nucleation ◽

Point Defect Clusters

ABSTRACTSmall precipitates of high lattice mismatch with respect to the matrix may be investigated by high resolution and high contrast moiré fringe images in TEM. One group of such precipitates are the MX-type precipitates with M = Ti, V, Zr, Nb, Hf, Ta, and X = C,N that form in austenitic steels. The usefulness of moiré images for the investigation of these MX-type precipitates is demonstrated and compared to other electron imaging and diffraction methods. The moiré technique has been used to study (a) nucleation and growth of precipitates, (b) the evolution of dual precipitate structures at grain boundaries, (c) morphology and faceting of small precipitates (∼10 nm diameter), (d) lattice parameter differences due to variation in precipitate chemical composition, (e) interaction of precipitates with dislocations, (f) gas atom trapping at precipitates, and (g) irradiation induced precipitate nucleation at point defect clusters.

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AEM analysis of crystallization in Ti-based amorphous alloys

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100075142 ◽

1983 ◽

Vol 41 ◽

pp. 270-271

Author(s):

A.R. Pelton ◽

A.F. Marshall ◽

Y.S. Lee

Keyword(s):

Magnetic Properties ◽

Amorphous Alloys ◽

Amorphous Materials ◽

Isothermal Annealing ◽

Amorphous Matrix ◽

Nucleation And Growth ◽

Current Interest ◽

Amorphous Films ◽

Electrical And Magnetic Properties

Amorphous materials are of current interest due to their desirable mechanical, electrical and magnetic properties. Furthermore, crystallizing amorphous alloys provides an avenue for discerning sequential and competitive phases thus allowing access to otherwise inaccessible crystalline structures. Previous studies have shown the benefits of using AEM to determine crystal structures and compositions of partially crystallized alloys. The present paper will discuss the AEM characterization of crystallized Cu-Ti and Ni-Ti amorphous films.Cu60Ti40: The amorphous alloy Cu60Ti40, when continuously heated, forms a simple intermediate, macrocrystalline phase which then transforms to the ordered, equilibrium Cu3Ti2 phase. However, contrary to what one would expect from kinetic considerations, isothermal annealing below the isochronal crystallization temperature results in direct nucleation and growth of Cu3Ti2 from the amorphous matrix.

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Observations oh Nucleation and Growth of Voids in Nickel

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100069065 ◽

1970 ◽

Vol 28 ◽

pp. 414-415

Author(s):

J. L. Brimhall ◽

H. E. Kissinger ◽

B. Mastel

Keyword(s):

High Purity ◽

Growth Stage ◽

Elevated Temperatures ◽

Early Growth ◽

Nucleation And Growth ◽

Pure Nickel ◽

Different Temperatures ◽

Total Fluence ◽

Neutron Exposure ◽

Growth Of Voids

Some information on the size and density of voids that develop in several high purity metals and alloys during irradiation with neutrons at elevated temperatures has been reported as a function of irradiation parameters. An area of particular interest is the nucleation and early growth stage of voids. It is the purpose of this paper to describe the microstructure in high purity nickel after irradiation to a very low but constant neutron exposure at three different temperatures.Annealed specimens of 99-997% pure nickel in the form of foils 75μ thick were irradiated in a capsule to a total fluence of 2.2 × 1019 n/cm2 (E > 1.0 MeV). The capsule consisted of three temperature zones maintained by heaters and monitored by thermocouples at 350, 400, and 450°C, respectively. The temperature was automatically dropped to 60°C while the reactor was down.

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Electrochemical nucleation and growth of copper on iron and aluminum: A TEM study of industrial copper cementation

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100109410 ◽

1978 ◽

Vol 36 (1) ◽

pp. 454-455

Author(s):

L.E. Murr ◽

V. Annamalai

Keyword(s):

Metal Surface ◽

Copper Deposit ◽

Nucleation And Growth ◽

16Th Century ◽

Electrochemical Reactions ◽

Mine Shaft ◽

De Re ◽

Copper Precipitation ◽

Electrochemical Nucleation ◽

Interesting System

Georgius Agricola in 1556 in his classical book, “De Re Metallica”, mentioned a strange water drawn from a mine shaft near Schmölnitz in Hungary that eroded iron and turned it into copper. This precipitation (or cementation) of copper on iron was employed as a commercial technique for producing copper at the Rio Tinto Mines in Spain in the 16th Century, and it continues today to account for as much as 15 percent of the copper produced by several U.S. copper companies.In addition to the Cu/Fe system, many other similar heterogeneous, electrochemical reactions can occur where ions from solution are reduced to metal on a more electropositive metal surface. In the case of copper precipitation from solution, aluminum is also an interesting system because of economic, environmental (ecological) and energy considerations. In studies of copper cementation on aluminum as an alternative to the historical Cu/Fe system, it was noticed that the two systems (Cu/Fe and Cu/Al) were kinetically very different, and that this difference was due in large part to differences in the structure of the residual, cement-copper deposit.

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