... distortions in the fixed stress field,
so
different amounts of work,
W,
must be done against the stress field during these
jumps. The rate of a particular jump in the absence of stress is proportional ... mobility should
vary linearly with stress and be expressible
as
a
tensor in the very general linear
form
(3. 78)
kl
where the stress-dependent terms in the sum are relati...
...
CONTENTS
12.2 Motion of Crystal/Vapor Interfaces
12.2.1 Structure of Crystal/Vapor Surfaces
12.2.2 Crystal Growth from a Supersaturated Vapor
12.2 .3 Surfaces as Sinks for Supersaturated Lattice ...
Kinetics
of
Materials
is the study of the rates
at
which various processes occur in
materials- knowledge of which is fundamental to materials science and engineer-
ing....
... interface curvature; when interfaces
possessing regions of different curvatures are present, differences in diffusion poten-
tial will drive diffusional transport between these regions in a direction ... follow from statements of the first and second laws of
thermodynamics.
Onsager s principle supplements these postulates and follows from the statisti-
cal theory of reversible f...
... forces-such as thermal gradients or electric fields-
'Such defects,
if
present, will be assumed to be in local thermal equilibrium at very small concen-
trations.
Kinetics
of
Materials. ... everywhere except where its argument is
zero, where it has an infinite singularity. It has the property
s
j(F')6(F-
Fo)dr'=
f (r& apos;0);
so
it also
follows that
s6 (F-...
... the ratio of strain over stress) is then
El
.E2
-
1-
-_
-
(~1
-
2~2)
eiWt
S( W)
=
uo
eiWt
uo
go
(8.71)
Because the strain lags behind the stress, the stress-strain curve for each ... mechanical response of
anelastic materials. Scalar forces in the spring and dashpot model become analogs
for a more complex stress tensor in materials. To enforce this an...
... diffusion on most surfaces is anisotropic because of their low two-dimensional
symmetry. When the surface structure consists
of
parallel rows of closely spaced
atoms, separated by somewhat larger ... somewhat larger inter-row distances, diffusion is usually easier
parallel to the dense rows than across them. In some cases,
it
appears that the
60ur
discussion follows reviews
by...
... boundary with isotropic surface energy
yB
intersects a free surface with
isotropic surface energy
ysl
a
grain-boundary groove
forms in order to achieve a
capillary-force balance, as illustrated ...
isotropic surfaces of larger constant mean curvature to particles of smaller constant
mean curvature. This coarsening process and the motion of internal interfaces due
to curvature...
... the grain center. The pressure due to this
curvature therefore induces growth. Grains with fewer than six sides show the
opposite behavior, whereas grains with six sides possess flat sides and ...
3Geometrical constructions for describing anisotropic surfaces are reviewed
in
Section
C .3. 1.
Some Geometrical Aspects of Anisotropic Surfaces
EXERCISES
35 5
14.2
Assume that self-dif...
...
ss .s
Surface Surface Surface diffusion Nondensifying
Atoms diffuse along the surface from larger-curvature surface regions to lower-
curvature surface regions.
ss.v
Surface Surface Vapor ... transport Nondensifying
Atoms are transported through the vapor phase from larger-curvature surface
regions to lower-curvature surface regions.
VF
- -
Viscous
flow
Either
Atoms are tr...
... the case of phase transformations) is absent and
the interface s core structure consists of all “bad material.” It is generally assumed
that any shear stresses applied across such an interface ... Clusters.
As described in Section
B.l,
for incoherent interfaces all of
the lattice registry characteristic of the reference structure (usually taken
as
the
crystal structure of...