scholarly journals Chemically induced grain boundary dynamics, forced motion by curvature, and the appearance of double seams

2002 ◽  
Vol 13 (1) ◽  
pp. 25-52 ◽  
Author(s):  
PAUL C. FIFE ◽  
XIAO-PING WANG
Keyword(s):  
Free Boundary ◽  
Grain Boundary ◽  
Extended Model ◽  
Forced Motion ◽  
Chemically Induced ◽  
Thin Film Model ◽  
Motion By Curvature ◽  
Boundary Model ◽  
Grain Boundary Motion ◽  
Boundary Dynamics

The free boundary model of diffusion-induced grain boundary motion derived in Cahn et al. [3], Fife et al. [6] and Cahn & Penrose [4] is extended, in the case of thin metallic films, to account for bidirectional motion, together with the appearance of S-shapes and double seam configurations. These are often observed in the laboratory. Computer simulations based on the extended model are given to illustrate these and other features of bidirectional motion. More generally, the extension accounts for the motion of grain boundaries whose traces on the film's surface are curved. The new free boundary model is one of forced motion by curvature, the forcing term possibly changing sign due to the bidirectionality. The thin film model is derived systematically under explicit assumptions, and an adjustment for grooving is included.

Grain Boundary Dynamics in High Magnetic Fields. Fundamentals and Implications for Materials Processing

2004 ◽  
Vol 467-470 ◽  
pp. 697-706 ◽  
Author(s):  
Dmitri A. Molodov
Keyword(s):  
Magnetic Fields ◽  
Grain Boundary ◽  
Boundary Migration ◽  
Materials Processing ◽  
High Magnetic Fields ◽  
Boundary Motion ◽  
Grain Boundary Mobility ◽  
Curvature Driven ◽  
Grain Boundary Motion ◽  
Boundary Dynamics

The latest research on dynamics of grain boundaries in non-magnetic materials in high magnetic fields is reviewed. A control of grain boundary migration means control of microstructure evolution, which is a key for the design of materials with desire properties. Grain boundary motion can be affected by a magnetic field, if the anisotropy of the magnetic susceptibility generates a gradient of the magnetic free energy. In contrast to curvature driven boundary motion, a magnetic driving force also acts on planar boundaries so that the motion of crystallographically well-defined boundaries can be investigated, and the true grain boundary mobility can be determined. The results of migration measurements obtained on bismuth and zinc bicrystals are addressed. Selective growth of new grains in locally deformed zinc single crystals driven by a magnetic force is reported as well. Implications for materials processing, in particular the effect of magnetic fields on texture development in hcp metals are finally discussed.

Atomic Mechanisms of Grain Boundary Motion

2005 ◽  
Vol 502 ◽  
pp. 157-162 ◽  
Author(s):  
A. Suzuki ◽  
Yuri M. Mishin
Keyword(s):  
Molecular Dynamics ◽  
Grain Boundary ◽  
Geometric Model ◽  
Lattice Rotation ◽  
Shear Stresses ◽  
Translation Rate ◽  
Embedded Atom ◽  
Local Lattice ◽  
Symmetrical Tilt ◽  
Grain Boundary Motion

We present results of atomistic computer simulations of spontaneous and stress-induced grain boundary (GB) migration in copper. Several symmetrical tilt GBs have been studied using the embedded-atom method and molecular dynamics. The GBs are observed to spontaneously migrate in a random manner. This spontaneous GB motion is always accompanied by relative translations of the grains parallel to the GB plane. Furthermore, external shear stresses applied parallel to the GB and normal to the tilt axis induce GB migration. Strong coupling is observed between the normal GB velocity vn and the grain translation rate v||. The mechanism of GB motion is established to be local lattice rotation within the GB core that does not involve any GB diffusion or sliding. The coupling constant between vn and v|| predicted within a simple geometric model accurately matches the molecular dynamics observations.

Coupled grain boundary motion in a nanocrystalline grain boundary network

2011 ◽  
Vol 65 (2) ◽  
pp. 151-154 ◽  
Author(s):  
M. Velasco ◽  
H. Van Swygenhoven ◽  
C. Brandl
Keyword(s):  
Grain Boundary ◽  
Boundary Motion ◽  
Grain Boundary Motion

Motion of Crystal/Crystal and Crystal/Amorphous Interfaces

1990 ◽  
Vol 183 ◽  
Author(s):  
J. L. Batstone
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Temperature ◽  
Grain Boundary ◽  
Boundary Motion ◽  
High Temperature Annealing ◽  
Thermally Activated ◽  
Transmission Electron ◽  
Grain Boundary Motion

AbstractMotion of ordered twin/matrix interfaces in films of silicon on sapphire occurs during high temperature annealing. This process is shown to be thermally activated and is analogous to grain boundary motion. Motion of amorphous/crystalline interfaces occurs during recrystallization of CoSi2 and NiSi2 from the amorphous phase. In-situ transmission electron microscopy has revealed details of the growth kinetics and interfacial roughness.

Grain boundary motion in particulate material

2020 ◽  
pp. 541-544
Author(s):  
J.L. Turner ◽  
M. Nakagawa ◽  
M.T. Lusk
Keyword(s):  
Grain Boundary ◽  
Particulate Material ◽  
Boundary Motion ◽  
Grain Boundary Motion
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