Reappraisal of grain boundary diffusion creep equations for nanocrystalline materials

2006 ◽  
Vol 12 (2) ◽  
pp. 107-113 ◽  
Author(s):  
Kyung-Tae Park ◽  
Chong Soo Lee ◽  
Dong Hyuk Shin ◽  
Yong Shin Lee ◽  
Won Jong Nam
Keyword(s):  
Grain Boundary ◽  
Nanocrystalline Materials ◽  
Boundary Diffusion ◽  
Grain Boundary Diffusion ◽  
Diffusion Creep

Modern Models of Grain Boundary Diffusion

2011 ◽  
Vol 312-315 ◽  
pp. 1116-1125
Author(s):  
Vladimir V. Popov
Keyword(s):  
Plastic Deformation ◽  
Grain Boundary ◽  
Severe Plastic Deformation ◽  
Nanocrystalline Materials ◽  
Boundary Diffusion ◽  
Grain Boundary Diffusion ◽  
Coarse Grained ◽  
Gas Condensation ◽  
Non Equilibrium

Recent models of grain-boundary diffusion are briefly reviewed. Models of diffusion along equilibrium boundaries of recrystallization origin in coarse-grained materials and along non-equilibrium boundaries in nanocrystalline materials obtained by gas condensation and compacting or by severe plastic deformation are considered separately.

Numerical Study of Grain Boundary Diffusion in Nanocrystalline Materials

2005 ◽  
Vol 237-240 ◽  
pp. 1043-1048 ◽  
Author(s):  
D. Gryaznov ◽  
J. Fleig ◽  
Joachim Maier
Keyword(s):  
Grain Boundary ◽  
Nanocrystalline Materials ◽  
Boundary Diffusion ◽  
Nanocrystalline Material ◽  
Numerical Study ◽  
Average Length ◽  
Type A ◽  
Grain Boundary Diffusion ◽  
Conventional Models ◽  
Diffusion Profiles

Diffusion in nanocrystalline materials is becoming an increasingly important topic. The analysis of diffusion profiles obtained in nanocrystalline materials with enhanced grain boundary diffusion, however, is not straightforward since assumptions made in the deviation of the conventional models are often not fulfilled. In this contribution numerical diffusion studies are performed in order to investigate effects caused by the high density of interfaces in nanocrystalline material. A continuum model based on the 2D 2-nd Fick’s law was solved by means of the finite element method. This allows us to analyze diffusion profiles for different geometrical situations such as a single boundary, square grains with the grain size of 80 nm and 25 nm and geometries comprising differently oriented boundaries of the average length of 30 nm . The analysis was carried out for different diffusion lengths corresponding to Harrison type A and type B kinetic regimes. For the isolated boundary a very good agreement was achieved in comparison with the classical Whipple’s solution. For nanocrystalline material, however, considerable errors can occur when analyzing the averaged diffusion profiles in the conventional Harrison type A and B kinetics.

Structure and Properties of Polycrystalline Materials From Simulation: An Interfacial Perspective

1999 ◽  
Vol 586 ◽  
Author(s):  
S. R. Phillpot ◽  
P. Keblinski ◽  
D. Wolf ◽  
F. Cleri
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Boundary Diffusion ◽  
Simulation Method ◽  
High Energy ◽  
Grain Boundary Diffusion ◽  
Dynamics Simulation ◽  
Polycrystalline Materials ◽  
Diffusion Creep ◽  
Fcc Metals

ABSTRACTWe have recently developed a novel molecular-dynamics simulation method to grow polycrystals from a melt containing randomly oriented crystalline seeds. The resulting microstructures contain only randomly oriented (i.e., high-energy) grain boundaries. We find that these grain boundaries, which are highly constrained by their close proximity to grain junctions, are highly disordered in fcc metals and amorphous in silicon. From simulations of infinitely extended high-energy grain boundaries in bicrystals, we find that such highly disordered and amorphous grain boundaries are actually the thermodynamic ground state; by contrast, low-energy grain boundaries are crystalline. High-energy grain boundaries in diamond, however, are structurally ordered at the expense of a significant amount of graphite-like bonding. We show that these complex grain boundary structures have important effects on properties including grain boundary diffusion (fcc metals and silicon), grain boundary diffusion creep (silicon) and grain boundary electrical activity and strength (diamond). The implications for engineering materials with prescribed properties are discussed.

Effects of grain growth on grain-boundary diffusion creep by molecular-dynamics simulation

2004 ◽  
Vol 52 (7) ◽  
pp. 1971-1987 ◽  
Author(s):  
A.J. Haslam ◽  
V. Yamakov ◽  
D. Moldovan ◽  
D. Wolf ◽  
S.R. Phillpot ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Grain Boundary ◽  
Grain Growth ◽  
Boundary Diffusion ◽  
Grain Boundary Diffusion ◽  
Dynamics Simulation ◽  
Diffusion Creep

Computer simulation of grain-boundary diffusion creep

2002 ◽  
Vol 50 (15) ◽  
pp. 3941-3955 ◽  
Author(s):  
J.M. Ford ◽  
J. Wheeler ◽  
A.B. Movchan
Keyword(s):  
Computer Simulation ◽  
Grain Boundary ◽  
Boundary Diffusion ◽  
Grain Boundary Diffusion ◽  
Diffusion Creep
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