Nucleation and Abnormal Grain Growth of Alpha-A12O3 in Gamma-Alumina Matrix

AbstractThe microstructures of reactive sputter-deposited alumina films have been studied by transmission electron microscopy. The as-deposited films contained γ-A12O3 phase in an amorphous alumina matrix. Annealing of the films at 1200° C for 2 h resulted in nucleation and concurrent anomalous grain growth of α-A12O3 in a polycrystaUine γ-Al2O3 matrix which exhibited a layered microstructure and was strongly textured along [001]. The grain sizes of α-A12O3 varied from 3 to 20 μm, while the average grain size of γ-A12O3 was only about 50 nm. It appears that the nucleation kinetics of a-A12O3 was slow. As a result, the abnormal grain growth of α-A12O3 proceeded by consuming surrounding γ-Al2O3 grains. An atomic model is presented to explain the origin of layered structure in γ-A12O3. The nucleation mechanism of a-A12O3 in γ-alumina matrix is suggested. Orientation relationships between γ- and α-A12O3 are reported. The anomalous grain growth of α- A12O3 is discussed in terms of γ/α interface boundary migration.

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An in situ transmission electron microscope investigation into grain growth and ordering of sputter-deposited nanocrystalline Ni3Al thin films

Journal of Materials Research ◽

10.1557/jmr.2002.0308 ◽

2002 ◽

Vol 17 (8) ◽

pp. 2085-2094 ◽

Cited By ~ 20

Author(s):

H. P. Ng ◽

A. H. W. Ngan

Keyword(s):

Electron Microscope ◽

Grain Growth ◽

Transmission Electron Microscope ◽

Growth Kinetics ◽

Abnormal Grain Growth ◽

Face Centered Cubic ◽

Transmission Electron ◽

Sputter Deposited ◽

Grain Growth Kinetics

The grain growth kinetics and ordering behavior of direct-current magnetron sputter-deposited Ni75at.%Al25at.% alloy films were investigated using in situ isothermal annealing in a transmission electron microscope. Both normal and abnormal grain growth modes were observed. The normal grain growth kinetics under isothermal heating from 300 to 700 °C were found to comply with the Burke law d = K/dn−1, where d is grain size and K and n are constants with respect to time. The grain boundary mobility parameter K was found to obey an Arrehnius rate law with an apparent activation energy of 1.6 eV, and n was found to increase gradually from 5.2 at 300 °C to 8.7 at 700 °C. Abnormal grain growth occurred at 500 °C or higher, and grain coalescence was identified as an important operative mechanism. It was also observed that the initially as-deposited state of the films was crystalline with a disordered face-centered-cubic structure, but ordering into the equilibrium L12 intermetallic structure followed from annealing at temperatures above approximately 500 °C.

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In Situ Hvem Study of Ion Irradiation-Induced Grain Growth in Au Thin Films

MRS Proceedings ◽

10.1557/proc-128-297 ◽

1988 ◽

Vol 128 ◽

Author(s):

Joyce C. Liu ◽

Jian Li ◽

J. W. Mayer ◽

Charles W. Allen ◽

Lynn E. Rehn

Keyword(s):

Grain Growth ◽

Room Temperature ◽

Ion Irradiation ◽

Boundary Migration ◽

Grain Boundary Migration ◽

Average Grain Size ◽

In Situ Observations ◽

Au Thin Films ◽

Grain Coalescence

ABSTRACTIn situ observations of 1.5 MeV Xe+ ion irradiated Au films at room temperature and at 150°C reveal the evolution of grain growth: the average grain size increases by the mechanisms of grain boundary migration and grain coalescence.

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Reactive phase formation in sputter-deposited Ni/Al multilayer thin films

Journal of Materials Research ◽

10.1557/jmr.1997.0021 ◽

1997 ◽

Vol 12 (1) ◽

pp. 133-146 ◽

Cited By ~ 93

Author(s):

K. Barmak ◽

C. Michaelsen ◽

G. Lucadamo

Keyword(s):

Phase Formation ◽

Molar Ratio ◽

X Ray Diffraction ◽

Nucleation Kinetics ◽

Scanning Calorimetry ◽

Calorimetric Analysis ◽

Transmission Electron ◽

Nial Phase ◽

Magnetron Sputter ◽

Sputter Deposited

We have investigated reactive phase formation in magnetron sputter-deposited NiyAl multilayer films with a 1 : 3 molar ratio and various periodicities, L, ranging from 320 nm down to a codeposited film with zero effective periodicity. The films were studied by x-ray diffraction, differential scanning calorimetry, electrical resistance measurements, and transmission electron microscopy. We find that Ni and Al have reacted during deposition to form the B2 NiAl phase and an amorphous phase. The formation of these phases substantially reduces the driving force for subsequent reactions and explains why nucleation kinetics become important for these reactions. Depending on the periodicity, these reactions result in the formation of NiAl3 or Ni2Al9 followed by NiAl3. Detailed calorimetric analysis reveals differences in the nucleation and growth behavior of NiAl3 compared with other studies.

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Evolution of phases and microstructure in optical waveguides of lithium niobate

Journal of Materials Research ◽

10.1557/jmr.1994.2040 ◽

1994 ◽

Vol 9 (8) ◽

pp. 2040-2050 ◽

Cited By ~ 10

Author(s):

M.A. McCoy ◽

S.A. Dregia ◽

W.E. Lee

Keyword(s):

Solid Solution ◽

Lithium Niobate ◽

Grain Growth ◽

Optical Waveguides ◽

Abnormal Grain Growth ◽

Microstructural Development ◽

X Ray Diffraction ◽

Rutile Structure ◽

Transmission Electron ◽

Epitaxial Grain Growth

The microstructural development of Ti: LiNbO3 optical waveguides, as a function of annealing time and temperature, was studied by x-ray diffraction, scanning and transmission electron microscopy, and Auger electron spectroscopy. The microstructure evolves in three major stages: oxidation, precipitation and abnormal grain growth, and interdiffusion. The deposited Ti film is oxidized at low temperatures through a series of intermediate TiOx phases until complete oxidation to rutile TiO2 occurs at ∼500 °C. At intermediate temperatures, 500-800 °C, epitaxial precipitates of LiNb3O8 are formed at the rutile/LiNbO3 interface. At this stage abnormal grain growth occurs in the rutile film, causing multivariant epitaxy where all of the grains have a single orientation relationship to the substrate. Subsequent interdiffusion between TiO2 and LiNb3O8 produces a solid solution with the rutile structure which, at these temperatures, appears to coexist in equilibrium with the underlying lithium niobate substrate. This rutile solid solution serves as the source of Ti in the final stage of interdiffusion, which occurs only at higher temperatures (≳ 1000 °C), and leads to consumption of the rutile layer by the substrate. Structural models are discussed for epitaxial grain growth and interdiffusion.

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A brief overview on grain growth of bulk electrodeposited nanocrystalline nickel and nickel-iron alloys

REVIEWS ON ADVANCED MATERIALS SCIENCE ◽

10.1515/rams-2019-0011 ◽

2019 ◽

Vol 58 (1) ◽

pp. 98-106

Author(s):

Haitao Ni ◽

Jiang Zhu ◽

Zhaodong Wang ◽

Haiyang Lv ◽

Yongyao Su ◽

...

Keyword(s):

Grain Size ◽

Grain Boundary ◽

Grain Growth ◽

Growth Process ◽

Boundary Migration ◽

Thermal Conditions ◽

Iron Alloys ◽

Nanocrystalline Nickel ◽

Nickel Iron ◽

Average Grain Size

Abstract This review focuses on grain growth behaviors and the underlying mechanisms of bulk electrodeposited nanocrystalline nickel and nickel-iron alloys. Effects of some important factors on grain growth are described. During thermal-induced grain growth process, grain boundary migration plays a key role. For similar thermal conditions, due to grain boundary mobility with solute drag, limited grain growth occurs in nanocrystalline alloys, as compared to pure metals. Nonetheless, in the case of stress-induced grain growth process, there are a variety of mechanisms in samples having various deformation histories. As an example the grain growth of nanocrystalline nickel and Ni-20%Fe alloy with nearly the same grain-size distribution and average grain size is compared in this paper. Thermal analysis indicates nanocrystalline nickel is much more prone to rapid grain growth than nanocrystalline Ni-20%Fe alloy. Nevertheless, grain growth of nanocrystalline Ni-20%Fe is found to be more pronounced than nanocrystalline nickel during rolling deformation.

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Abnormal grain growth of sputtered CuNi(Mn) thin films

Journal of Materials Research ◽

10.1557/jmr.2000.0153 ◽

2000 ◽

Vol 15 (5) ◽

pp. 1062-1068 ◽

Cited By ~ 3

Author(s):

W. Brückner ◽

V. Weihnacht ◽

W. Pitschke ◽

J. Thomas ◽

S. Baunack

Keyword(s):

Thin Films ◽

Grain Growth ◽

Abnormal Grain Growth ◽

Temperature Cycle ◽

X Ray Diffraction ◽

Transmission Electron ◽

Columnar Grains ◽

Maximum Temperatures ◽

Film Substrate ◽

20 Nm

The evolution in both stress and microstructure was investigated on sputtered Cu0.57Ni0.42Mn0.01thin films of 400 nm thickness during the first temperature cycle up to 550 °C. Samples from stress–temperature measurements up to various maximum temperatures were analyzed by x-ray diffraction, scanning and transmission electron microscopy, and Auger electron spectroscopy. The columnar grains with lateral diameters of about 20 nm in the as-deposited state coarsen to about 400 nm above 300 °C. Probably due to the impurity (Mn) drag effect, the coarsening occurs by abnormal grain growth rather than by normal grain growth, starting near the film–substrate interface. The stress development results from a combination of densification due to grain growth and plastic stress relaxation.

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Texture Change during Grain Growth in Non-Oriented Electrical Steel

Materials Science Forum ◽

10.4028/www.scientific.net/msf.753.329 ◽

2013 ◽

Vol 753 ◽

pp. 329-332

Author(s):

Yoshihiro Arita ◽

Yoshiyuki Ushigami ◽

Kenichi Murakami ◽

Kohsaku Ushioda

Keyword(s):

Grain Growth ◽

Electrical Steel ◽

Abnormal Grain Growth ◽

Initial Structure ◽

Rolled Steel ◽

Ebsd Data ◽

Texture Change ◽

Average Grain Size ◽

Cold Rolled ◽

Initial Texture

Texture change during grain growth in Fe-3%Si non-oriented electrical steel was investigated. Cold rolled steel, 0.35mm in thickness, was annealed and recrystallized as an initial structure. Normal grain growth and abnormal grain growth occurred by additional annealing. {111} was dominant in the initial texture. However {100} component, which was not in majority in the initial structure, became stronger after normal grain growth. It was revealed that an average grain size of {100} in the initial structure was bigger than those of other components by analysis of the EBSD data,. Therefore, it is concluded that {100} strengthened after normal grain growth due to its size advantage. On the other hand, {111} components became more stronger after abnormal grain growth. It is inferred that another mechanism of the texture change worked in abnormal grain growth.

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Grain Growth in Titanium Silicide Films During the Formation Reaction

MRS Proceedings ◽

10.1557/proc-202-137 ◽

1990 ◽

Vol 202 ◽

Author(s):

Yunji L. Corcoran ◽

Alexander H. King ◽

Nimal deLanerolle ◽

Bonggi Kim ◽

John Berg

Keyword(s):

Growth Rate ◽

Grain Growth ◽

Cross Section ◽

Titanium Silicide ◽

Silicon Substrates ◽

Experimental Conditions ◽

Silicide Layer ◽

Transmission Electron ◽

Sputter Deposited ◽

Relationship Of

ABSTRACTTitanium films of 0.5 µm thickness were sputter deposited on silicon substrates. After rapid thermal annealing at temperatures ranging from 600°C to 850°C for times up to 45 seconds in nitrogen, transmission electron microscope (TEM) cross section specimens were made from the wafers. Grain sizes of the resulting titanium disilicide were measured from TEM cross section micrographs. The results show that C49-TiSi2 has a different grain growth rate than C54-TiSi2- Under our experimental conditions, C54-TiSi2 has a much higher growth rate. Titanium silicide on arsenic implanted silicon substrates shows a lower grain growth rate than that on unimplanted substrates under the same conditions. The thickness of the silicide layer was also measured for each specimen. The relationship of thickness and grain size will be discussed.

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The effect of secondary abnormal grain growth on the dielectric properties of La/Mn co-doped BaTiO3 ceramics

Science of Sintering ◽

10.2298/sos0603273z ◽

2006 ◽

Vol 38 (3) ◽

pp. 273-281 ◽

Cited By ~ 5

Author(s):

Lj.M. Zivkovic ◽

V.V. Paunovic ◽

N.Lj. Stamenkov ◽

M.M. Miljkovic

Keyword(s):

Grain Growth ◽

Ferroelectric Phase ◽

Eutectic Temperature ◽

Ferroelectric Properties ◽

Abnormal Grain Growth ◽

Solid State Reactions ◽

Dielectric Parameters ◽

High Electrical Resistivity ◽

Uniform Microstructure ◽

Average Grain Size

La/Mn-codoped BaTiO3 systems, obtained by solid state reactions, were investigated regarding their microstructure characteristics and ferroelectric properties. Different concentrations of La2O3 were used for doping, ranging from 0.1 to 5.0 at% La, while a content of Mn was constant at 0.05 at%. For all samples sintered below the eutectic temperature (1332?C), a uniform microstructure was formed with average grain size from 1-3 ?m. The appearance of secondary abnormal grains with (111) double twins grains with curved or faceted grain boundaries were observed in La/Mn BaTiO3 ceramics after sintering at temperatures above the eutectic temperature. All sintered samples exhibited a high electrical resistivity. Better dielectric performances were obtained for low doped samples (0.1 at% La) sintered at 1350?C. For samples with La content above 1.0 at% a lower value in dielectric permittivity at higher sintering temperature is due to secondary abnormal grain growth, and to the presence of a non-ferroelectric phase rich in La. The Curie constant together with other dielectric parameters were also calculated.

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