A numerical study of cavity growth controlled by coupled surface and grain boundary diffusion

1982 ◽  
Vol 13 (3) ◽  
pp. 427-437 ◽  
Author(s):  
L. Martinez ◽  
W. D. Nix
Keyword(s):  
Grain Boundary ◽  
Boundary Diffusion ◽  
Numerical Study ◽  
Cavity Growth ◽  
Grain Boundary Diffusion

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.

Effect of Elastic Accommodation on Diffusion-Controlled Cavity Growth in Metals

2000 ◽  
Vol 122 (3) ◽  
pp. 294-299
Author(s):  
R. Mohan ◽  
J. Zhang ◽  
F. W. Brust
Keyword(s):  
Grain Boundary ◽  
Growth Rates ◽  
Void Growth ◽  
Boundary Diffusion ◽  
Virtual Work ◽  
Cell Model ◽  
Cavity Growth ◽  
Grain Boundary Diffusion ◽  
Transient Time ◽  
Diffusion Controlled

The effect of elastic accommodation on the grain boundary diffusion-controlled void growth was analyzed using an axisymmetric unit cell model. An incremental form of the virtual work principle was used to formulate the boundary value problem involving grain boundary diffusion. The model accounts for material elasticity and void interaction effects. Analyses are performed for initially spherical voids spaced periodically along the grain boundary. The results of the analyses on void growth rates agree well with the Hull-Rimmer model after the initial transient time. During the elastic transient, void growth rates can be several orders of magnitude higher than the steady state growth rate. Though the elastic transient time may occupy a small portion of the total rupture time, in metallic components experiencing cyclic loading conditions with short hold times, elasticity effects may be important. [S0094-4289(00)00903-8]

A simplified model for cavity growth along a grain-boundary by coupled surface and grain-boundary diffusion

2000 ◽  
Vol 19 (1) ◽  
pp. 17-30 ◽  
Author(s):  
Chris Westwood ◽  
Jingzhe Pan ◽  
Huirong Le ◽  
Sergei Kucherenko ◽  
Andy Crocombe
Keyword(s):  
Grain Boundary ◽  
Boundary Diffusion ◽  
Cavity Growth ◽  
Grain Boundary Diffusion ◽  
Simplified Model
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