Grain-boundary diffusion rates inferred from grain-size variations of quartz in metacherts from a contact aureole

2013 ◽  
Vol 98 (4) ◽  
pp. 680-688 ◽  
Author(s):  
T. Okudaira ◽  
H. Bando ◽  
K. Yoshida
Keyword(s):  
Grain Size ◽  
Grain Boundary ◽  
Boundary Diffusion ◽  
Grain Boundary Diffusion ◽  
Contact Aureole ◽  
Diffusion Rates

Analysis of Creep Deformation Due to Grain-Boundary Diffusion/Sliding

2007 ◽  
Vol 345-346 ◽  
pp. 565-568
Author(s):  
Byung Nam Kim ◽  
Keijiro Hiraga ◽  
Koji Morita ◽  
Hidehiro Yoshida
Keyword(s):  
Grain Size ◽  
Creep Rate ◽  
Grain Boundary ◽  
Boundary Diffusion ◽  
Effective Diffusion ◽  
High Viscosity ◽  
Grain Boundary Sliding ◽  
Grain Boundary Diffusion ◽  
Grain Sizes ◽  
Boundary Sliding

For steady-state deformation caused by grain-boundary diffusion and viscous grain-boundary sliding, the creep rate of regular polyhedral grains is analyzed by the energy-balance method. For the microstructure, the grain-grain interaction increases the degree of symmetry of diffusional field, resulting in a decrease of the effective diffusion distance. Meanwhile, the viscous grain-boundary sliding is found to decrease the creep rate. The present analysis reveals that the grain-size exponent is dependent on the grain size and the grain-boundary viscosity: the exponent becomes unity for small grain sizes and/or high viscosity, while it is three for large grain sizes and/or low viscosity.

The influence of grain size on the grain boundary diffusion

1974 ◽  
Vol 24 (3) ◽  
pp. 343-346 ◽  
Author(s):  
Z. Knésl ◽  
J. Jinoch ◽  
Z. Bílek
Keyword(s):  
Grain Size ◽  
Grain Boundary ◽  
Boundary Diffusion ◽  
Grain Boundary Diffusion

Boron Diffusion in Polycrystalline Silicon

1986 ◽  
Vol 76 ◽  
Author(s):  
Moustafa Y. Ghannam ◽  
Robert W. Dutton ◽  
Steven W. Novak
Keyword(s):  
Grain Size ◽  
Diffusion Coefficient ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Polycrystalline Silicon ◽  
Boundary Diffusion ◽  
Crystalline Silicon ◽  
Unit Area ◽  
Grain Boundary Diffusion ◽  
Boron Diffusion

ABSTRACTThe diffusion of boron in ion implanted LPCVD polycrystalline silicon is shown to be dominated by grain boundary diffusion at low and moderate concentrations. The diffusion coefficient is 2 to 3 orders of magnitude larger than its value in crystalline silicon. In preannealed polysilicon, the boron diffusion coefficient is found to be 30% smaller than in polysilicon annealed after implantation. This reflects the effect of the grain size in the diffusion coefficient since preannealed polysilicon has larger grains and smaller density of grain boundaries per unit area.

Relationship between Grain Boundary Diffusion and Ferrite Grain Size Formed through Dynamic Recrystallization during Large Strain Deformation

2007 ◽  
Vol 558-559 ◽  
pp. 595-600 ◽  
Author(s):  
Shiro Torizuka ◽  
S.V.S. Narayana Murty
Keyword(s):  
Grain Size ◽  
Grain Boundary ◽  
Boundary Diffusion ◽  
Large Strain ◽  
Grain Boundary Diffusion ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Low Carbon ◽  
Hollomon Parameter ◽  
Ferrite Grain Size

During large strain deformation of materials, the high angle grain boundary spacing approaches the order of mean thermal diffusion distances for given deformation conditions. Based on the results of microstructural and grain size analysis in low carbon steel subjected to large strain-high Z deformation, the evolved ferrite grain size was found to be controlled by the Zener-Hollomon parameter and grain boundary diffusion was found to be the controlling mechanism.

scholarly journals Shift of Creep Mechanism in Nanocrystalline NiAl Alloy

Materials ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 2508
Author(s):  
Zhihui Sun ◽  
Baoshu Liu ◽  
Chenwei He ◽  
Lu Xie ◽  
Qing Peng
Keyword(s):  
Grain Size ◽  
Dislocation Density ◽  
Grain Boundary ◽  
Boundary Diffusion ◽  
Volume Fraction ◽  
Grain Boundary Diffusion ◽  
Creep Mechanism ◽  
Creep Process ◽  
Nial Alloy ◽  
Coble Creep

We have examined the effects of temperature, stress, and grain size on the creep process including creep strain, crystal structure, dislocations and diffusions of nanocrystalline NiAl alloy through molecular dynamics simulations. A smaller grain size accelerates the creep process due to the large volume fraction of grain boundaries. Higher temperatures and stress levels also speed up this process in terms of dislocation changes and atom diffusion. In both primary creep and steady-state creep stages, atomic diffusion at the grain boundary could be seen and the dislocation density increased gradually, indicating that the creep mechanism at these stages is Coble creep controlled by grain boundary diffusion while accompanied by dislocation nucleation. When the model enters the tertiary creep stage, it can be observed that the diffusion of atoms in the grain boundary and in the crystal and the dislocation density gradually decreases, implying that the creep mechanisms at this stage are Coble creep, controlled by grain boundary diffusion, and Nabarro–Herring creep, controlled by lattice diffusion.

Effect of Surface and Grain-Boundary Diffusion on Interconnect Reliability

1995 ◽  
Vol 391 ◽  
Author(s):  
L. M. Klinger ◽  
E. E. Glickman ◽  
V. E. Fradkov ◽  
W. W. Mullins ◽  
C. L. Bauer
Keyword(s):  
Grain Size ◽  
Steady State ◽  
Grain Boundary ◽  
Boundary Diffusion ◽  
Grain Boundary Diffusion ◽  
Polycrystalline Materials ◽  
Interconnect Reliability ◽  
The Stability ◽  
Boundary Flux ◽  
Effect Of Surface

AbstractThe effect of surface and grain-boundary diffusion on interconnect reliability is addressed by extending the theory of thermal grooving to arbitrary grain-boundary flux. For a periodic array of grain boundaries, three regimes are identified: (1) equilibrium, (2) global steady state, and (3) local steady state. These regimes govern the stability of polycrystalline materials subjected to large electric (electromigration) or mechanical (stress voiding) fields, especially in thin films where grain size approximates film thickness.

The Effect of Grain-Boundary Diffusion on the Oxidation of Low-Chromium Steels

2005 ◽  
Vol 237-240 ◽  
pp. 946-951 ◽  
Author(s):  
Ulrich Krupp ◽  
V.B. Trindade ◽  
Peter Schmidt ◽  
Hans Jürgen Christ ◽  
U. Buschmann ◽  
...  
Keyword(s):  
Grain Size ◽  
Grain Boundary ◽  
Boundary Diffusion ◽  
Grain Boundary Diffusion ◽  
Transport Processes ◽  
Gradual Transition ◽  
Oxide Growth ◽  
Low Alloy Steels ◽  
Data Set ◽  
Cr Steels

Even though the oxidation behavior of steels is generally considered as to be widely understood, a closer look reveals some open questions, e.g. regarding the influence of the substrate grain size on the overall oxidation kinetics. At temperatures below 570°C the main constituent of the oxide scale formed on top of low alloy steels is magnetite. As shown by gold marker experiments it grows outward and inward at the same time, the latter exhibiting a gradual transition to the more stable spinel compound FeCr2O4. As indicated by intergranular-oxidation attack below the superficial scale, inward oxide growth seems to be driven by oxygen transport along the grain boundaries serving as fast diffusion paths. This is supported by thermogravimetric oxidation tests in air on low-Cr steels with varying grain size: The smaller the grains the higher the oxidation rate. Recently, a numerical model for the diffusive transport processes based on the finite-difference approach has been developed, which distinguishes between fast grain-boundary diffusion and bulk diffusion. Qualitatively, it is capable to predict the relationship between substrate grain size and inward oxide growth kinetics. Together with the thermodynamic tool ChemApp and in combination with a data set for the Fe-Cr-O system the mechanism-based simulation of the overall oxidation process of low-Cr steels is possible.

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