The Experts below are selected from a list of 261 Experts worldwide ranked by ideXlab platform
Carl V. Thompson - One of the best experts on this subject based on the ideXlab platform.
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stress and Grain Growth in thin films
Journal of The Mechanics and Physics of Solids, 1996Co-Authors: Carl V. Thompson, R CarelAbstract:Abstract The mechanical properties of polycrystalline thin films with thickness of 1 μm or less depend strongly on the Grain geometry, the Grain size, and the way in which the crystallographic orientations of the Grains are distributed. Grain Growth during film formation or during post-deposition annealing can play a dominant role in defining these microstructural characteristics, and therefore, the mechanical properties of films. Stress can suppress or promote Grain Growth. In the latter case, stress promotes texture evolution during Grain Growth. Grain Growth can serve as a stress relief mechanism in both elastically isotropic and anisotropic materials, and can also promote plastic yielding.
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Grain Growth in thin films
Annual Review of Materials Science, 1990Co-Authors: Carl V. ThompsonAbstract:in the average crystal orientation and can even result in epitaxial films. It is therefore not surprising that Grain Growth can profoundly affect the mechanical, electrical, and chemical properties of thin films. In this article the mechanisms and modes of Grain Growth in thin films will be reviewed. The focus will be on those factors that lead to the evolution of Grain orientations as well as Grain si zes. Spec ific attention will also be gi ven to those factors that allow control of microstructural evolution in thin films.
Gary L. Messing - One of the best experts on this subject based on the ideXlab platform.
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sintering and Grain Growth in sio2 doped nd yag
Journal of The European Ceramic Society, 2008Co-Authors: Sujarinee Kochawattana, Adam J Stevenson, M O Ramirez, Venkatraman Gopalan, John Q Dumm, Vida K Castillo, Gregory J Quarles, Gary L. MessingAbstract:Abstract Densification and Grain Growth in pure YAG, SiO 2 doped YAG and SiO 2 doped Nd:YAG were explored. The activation energy for densification (235 kJ/mol) in pure YAG is lower than that of Grain Growth (946 kJ/mol) which is unusual in ceramic systems. Consequently, pure YAG sinters to near full density (>99.9%) at 1700 °C with little Grain Growth (1.2 μm average Grain size). The remaining large pores (radius > 2 μm) were determined to be thermodynamically stable because their coordination number with Grains was >6. The stability of these pores underscores the importance of powder processing and forming in fabricating transparent YAG. SiO 2 doped YAG sinters to near full density 100 °C lower than pure YAG because SiO 2 enables liquid phase sintering and the removal of large pores. The addition of Nd 2 O 3 further enhances both densification and Grain Growth at temperatures below 1700 °C. Above 1700 °C higher concentrations of Nd 3+ suppressed Grain Growth, possibly due to solute drag.
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Densification and anisotropic Grain Growth in Sr2Nb2O7
Journal of Materials Science, 2000Co-Authors: B. Brahmaroutu, Gary L. Messing, Susan Trolier-mckinstryAbstract:Sr : Nb stoichiometry and donor-doping with La were found to affect densification behavior and anisotropic Grain Growth in Sr2Nb2O7 ceramics. La-doping improved the high temperature a.c. resistivity, but inhibits Grain Growth by Grain boundary pinning. The presence of excess Nb was found to promote anisotropic Grain Growth by forming a liquid at the Grain boundaries in both undoped and doped Sr2Nb2O7. Anisotropic Grain Growth in La-doped Sr2Nb2O7 can be controlled by incorporating large template particles in a Nb-rich matrix. High sintered densities (∼98% of theoretical) were achieved in both undoped and La-doped samples.
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Anisotropic Grain Growth in TiO2-doped alumina
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 1995Co-Authors: Debra S. Horn, Gary L. MessingAbstract:Abstract Grain Growth in TiO 2 -doped alumina was studied in a high density, ultrafine matrix (0.4 μm. Normal Grain Growth, anisotropic Grain Growth and abnormal Grain Growth were observed. With 0.15-0.4 wt.% TiO 2 , samples initially undergo normal Grain Growth until a crystal microstructure is attained and anisotropic Grain Growth in nucleated. Large anisotropic, platelet-shaped Grains grow rapidly by a step Growth process until impingement of the large Grains essentially stops further Growth. The volume fraction of anisotropic Grains ranged from 20 to 100 vol.% suggesting that physical properties dependent on Grain shape and volume fraction can be tailored. Critical requirements are proposed for the in situ Growth of anisotropic Grains.
R Carel - One of the best experts on this subject based on the ideXlab platform.
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stress and Grain Growth in thin films
Journal of The Mechanics and Physics of Solids, 1996Co-Authors: Carl V. Thompson, R CarelAbstract:Abstract The mechanical properties of polycrystalline thin films with thickness of 1 μm or less depend strongly on the Grain geometry, the Grain size, and the way in which the crystallographic orientations of the Grains are distributed. Grain Growth during film formation or during post-deposition annealing can play a dominant role in defining these microstructural characteristics, and therefore, the mechanical properties of films. Stress can suppress or promote Grain Growth. In the latter case, stress promotes texture evolution during Grain Growth. Grain Growth can serve as a stress relief mechanism in both elastically isotropic and anisotropic materials, and can also promote plastic yielding.
Wolfdieter Schubert - One of the best experts on this subject based on the ideXlab platform.
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wc Grain Growth and Grain Growth inhibition in nickel and iron binder hardmetals
International Journal of Refractory Metals & Hard Materials, 2002Co-Authors: Bernhard Wittmann, Wolfdieter SchubertAbstract:Abstract WC Grain Growth and Growth inhibition of an 0.6 μm FSSS WC powder (average SEM size: 0.35 μm) were studied in WC–10 wt% Ni alloys by adding 0–2 wt% of inhibitor carbides (VC, Cr 3 C 2 , TaC, TiC and ZrC). Alloy gross carbon content turned out to be a crucial factor for WC Growth in Ni alloys, even with high inhibitor additions. Coarsening was more pronounced in high carbon alloys, compared with low carbon grades, resulting in a significantly lower hardness. VC proved to be by far the most effective Grain Growth inhibitor in WC–Ni hardmetals, followed by TaC, Cr 3 C 2 , TiC and ZrC. Hardness increased with increasing amount of additive but reached a maximum above which it remained about the same. Experiments on WC–Fe–(VC) alloys revealed that WC Grain Growth is strongly restricted in Fe-binder alloys, even without additions of Growth inhibitors. Binder chemistry thus strongly influences both continuous and discontinuous WC Grain Growth. This chemistry is determined by the nature of the binder matrix (Fe, Co, Ni), the alloy gross carbon content (which determines the composition of the binder matrix) as well as the inhibitor additive.
J F Bingert - One of the best experts on this subject based on the ideXlab platform.
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high pressure torsion induced Grain Growth in electrodeposited nanocrystalline ni
Applied Physics Letters, 2006Co-Authors: X Z Liao, A R Kilmametov, R Z Valiev, Xiaodong Li, A K Mukherjee, J F BingertAbstract:Deformation-induced Grain Growth has been reported in nanocrystalline (nc) materials under indentation and severe cyclic loading, but not under any other deformation mode. This raises an issue on critical conditions for Grain Growth in nc materials. This study investigates deformation-induced Grain Growth in electrodeposited nc Ni during high-pressure torsion (HPT). Our results indicate that high stress and severe plastic deformation are required for inducing Grain Growth, and the upper limit of Grain size is determined by the deformation mode and parameters. Also, texture evolution suggests that Grain-boundary-mediated mechanisms played a significant role in accommodating HPT strain.
