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On Equilibrium and Stationary Coefficients of Grain Boundary Segregation B.S.
Grain boundary (GB) segregation is usually characterized by two different coefficients: either b, which is used in the isotherm of equilibrium adsorption (Langmuir, McLean etc.) or s, which can be determined as a ratio of grain boundary and bulk concentration in the immediate vicinity of grain boundary.
Grain Boundary Diffusion and Grain Boundary Segregation (Scitec Publ., Switzerland 1998)
McLean: Grain Boundaries in Metals (Clarendon press, England 1957)
Gust: Fundamentals of Grain and Interface Boundary Diffusion (Wiley, Chichester, N.

At the same time, grain and the second phase is not easy to grow, grain boundaries are also smaller.
During the artificial aging treatment, it producing a large number of dislocations and sub grain [8], the alloy in the second 120 ℃ aging treatment greatly increased the number of recrystallization nuclei, and thus grain refinement.
When the material is subjected to stress, first in the grain crystal defects in or along the crystallographic required energy minimum slip surface formation of dislocation, dislocation in grain continuously expand.
The first is the strengthening of grain.
After 480℃/80min + aging in 120℃/4h + cryogenic treatment + aging at 120℃/16h, on the microstructure of 7A04 aluminum alloy by recrystallization and refined the grain, thus, increasing the grain boundary area.

After a certain number of operating cycles of making and breaking operations, contacts are often destroyed catastrophically although their total commutation wear is not very severe at the moment.
Microstructure transformation investigations of the contact material were carried out successively after different numbers of making and breaking operation cycles by Hitachi S-570 scanning electron microscope and Neophot II optical microscope.
If there are oxides exist along grain boundaries, the binding force of recrystallized columnar grains is weakened.
Based on vast number of electrical tests simulating the servicing conditions on equipment similar to that described in reference [6] (U=380V, I=30A, cosϕ=0.35, with no arc quenching), the relation between the matrix grain size and duration times of the Cu-Cd-Nb-CP composite was concluded and results are given in fig. 5.
It shows that the number of cycles N increases 4-5 times when the particles size of Nb decreases from ∼40 µm to ∼20 µm and then changes slightly.

Grain size 0,5 µµµµm Fig. 3.
The alternation in temperature dependence of conductivity in different temperature ranges is well known and appears in a number of oxide materials, and is attributed to a change in the dominating charge transport mechanism.
As a comparison a number of results from previous research on polycrystalline alumina is shown.
Ref [11] undoped, average grain size 3 µm, relative density 99.5%.
Ref [16] MgO doped, average grain size 20 µm.

The latter was counted as the fraction of grains with grain orientation spread below 1°.
The microstructure after annealing at 500 °C is characterized by fully recrystallized structure with a number of annealing twins.
Figure 2 shows the inverse pole figure (IPF), the grain orientation spread (Grain Orient.
Inverse pole figure (IPF) for the rolling direction with grain boundary misorientation distribution (q), grain orientation spread (Grain Orient.
Inverse pole figure (IPF) for the rolling direction with grain boundary misorientation distribution (q), grain orientation spread maps (Grain Orient.

A phase mixture model is employed to describe the deformation behaviour of ultra fine grained materials (down to the nanometer grain size scale).
Equation (5) describes a viscous Newtonian flow law, where a generalised viscosity depends on the grain size and the grain boundary selfdiffusion coefficient.
With higher number of ECAP passes the fraction of high angle grain boundaries increases.
TEM investigation of the 16 pass specimen revealed non-equilibrium grain boundaries combined with equiaxed grains.
It can be conjectured that an enhanced grain boundary sliding as well as grain rotation may occur during deformation of such materials leading to increased ductility.

With an increase in the substrate temperature, tight grain boundaries are formed between the growing columnar grains.
Finally, zone III (0.5 grains and a bright smooth surface due to the grain growth driven by bulk diffusion.
The void between grain columns decreased and the width of the grain columnar increased slightly.
The result was attributed to the zone II structure of the SZM (tight grain boundaries and faceted grains).
Acknowledgments This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT & Future Planning (grant number: 2019R1H1A2101121).

As discussed above, because a large number of t-ZrO2 nano-micron fibers are embedded in the rod-shaped sapphire, there are a large number of fine heterophase interfaces in the rod-shaped sapphire.
According to the analyses of Sayir [5], a large number of fine low energy heterophase interfaces established during eutectic solidification cause the rod-shaped sapphire to be reinforced.
In addition, as the crack bypasses the rod-shaped sapphires, it is inevitably met by the nearby large plate-like α-Al2O3 grains.
Subsequently, as the crack becomes trapped the nearby rod-shaped sapphires, secondary microfractures develop along the boundaries of the bridging grains and the frictionally interlocked grains are formed, and frictionally interlocked toughening effect by the large plate-like α-Al2O3 grains is initiated.
A large number of fine low energy heterophase interfaces and the strong compressive residual stresses in the rod-shaped sapphires make the sapphires reinforced, and major toughening mechanisms are the fracture energy consumed in creating the debonded interfaces and the stored strain energy in the rod-shaped sapphires, followed by the frictionally interlocked effect of the plate-like α-Al2O3 grains.

After straining to 4 the (sub)grain size attains 0.65 µm.
The mechanism of cDRX includes the appearance of a number of strain-induced low-angle subboundaries (LABs) at relatively small deformation and then the significant increase in the misorientations among the subgrains leading to the formation of UFGs surrounded by high-angle boundaries (HABs) at large strains.
The pressing leads to large number of low-angle strain-induced subboundaries (θ<15°) crossing initial grains and DMBs.
The number of UFG increases significantly in the strain range of 2<ε<4.
The effect of ECAP pass number on the strength and the elongation is shown in Fig. 3.

. *** (2004) pp.573-576 online at http://scientific.net Ó 2004 Trans Tech Publications, Switzerland Fine-grained Access Control of PDM and CAPP S.H.
The function of fine-grained access control system was presented.
Based on RBAC, it is feasible to realize the fine-grained access control for the integrated PDM and CAPP system on the Web application layer.
To keep data resources from being damaged, attacked and stolen, a fine-grained access control model for PDM and CAPP was set up.
R&D Program for CIMS of China under Grant number 2001AA412120.