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From the studies of densification process [2,4-6] and diffusion process [8-10] in Fe-Ni nanomaterials, it has been reported that the hierarchical type of grain boundaries consisting of nano grain boundary and agglomerate boundary act as high diffusion paths for densification process (Fig.1).
Especially it was found that atoms diffuse much faster along agglomerate boundaries compared to nano grain boundary.
Such structural hierarchy consisting of nano grain boundary and agglomerate boundary strongly depends on agglomerate size.
Fig. 5 discloses hierarchical structure consisting of large agglomerate boundaries and nano grain boundaries in the same PIMed specimen.
It is obvious that a large number of γ phase are precipitated along agglomerate boundaries.

As demonstrated in earlier reports [6-9], the initial grain size of d ≈ 1 mm was refined to d ≈ 1.3 µm in high-purity Al after pressing through 4 passes and these ultrafine grains were reasonably equiaxed.
Flow mechanisms in creep When materials have very small grain sizes, the creep behavior is usually dictated by the occurrence of diffusion creep or grain boundary sliding (GBS).
For grain boundary sliding, the precise flow mechanism is dependent upon whether the grain size is larger or smaller than the equilibrium subgrain size.
Fig. 2 Logarithmic plot of minimum creep rate versus applied stress for an as-received specimen tested at a temperature of 473 K under a constant stress of 20 MPa without ECAP processing and for a number of specimens processed by ECAP and subsequently creep tested at different levels of constant stress at 473 K [15,16].
Svoboda, in: Ultrafine Grained Materials III, edited by Y.T.

Grain identification angle: 15 �.
Grain size observed is finer in the TRC samples than in DC samples.
Band contrast is EBSD pattern quality numbers.
Deformed regions and grain boundaries usually have a low band contrast value [11].
The grain boundaries and shear band regions had low contrast as usual, and undeformed large grains had high contrast.

The Raman spectroscopy result shows that the SiC polytype was 6H, the SiC grains distributions are homogeneous, and the size of the SiC grains is uniform and dense.
Various parameters including gas pressure, temperature field distribution, gas phase component and seeds quality are playing important role in the process of crystal growth, and these parameters are correlated, which means effective control is hard to realize, therefore, a large number of micropipes, dislocation, stacking fault, small angle grain boundaries and other defects will exist in the prepared silicon carbide crystal[5-9].
Fig. 4 Raman spectrum of 6H-SiC grain.
Fig. 5(b) is the FESEM image of the grown SiC grains.
Fig. 5 (a) Photograph of the SiC grains; (b) FESEM image of the SiC grains.

The resulting microstructure was homogenous with a 20 µm average grain size.
By covering the maximum surface of a polar grid, this method enabled us to obtain the stored energy for a large number of orientations, and in particular, it provided accurate values for the deformation texture components.
Therefore an orientation gradient of about 1°/µm was observed [7]. 1.2 Morphology of the {111} <110> grains Unlike the {111}<112> grains, the {111}<110> grains showed equiaxed deformation cells whatever the deformation mode (Fig. 2).
TEM substructure according to the {111}<110>: a): after cold rolling, b): after tension. 1.3 Morphology of the {001} <110> grains After rolling, the grains {001}<110> as well as the grains {111}<110>, showed an equiaxed substructure (Fig. 3a).
For the 40% cold rolled {111}<112> grains [13], the values of d, D and e (e = deformed grain thickness in the plane (RD, ND)) are equal to 0.5, 2 and 10 µm respectively.

A matrix of ferrite to pearlite grains is noted as shown in Figure 2.
Steel Pro-eutectoid Ferrite (%) Perlite (%) Grain Size (µm) Microligado A913 89,8 10,2 5,6 1013A 70,4 29,7 4,3 1013B 85,5 14,5 5,1 A measure of the number of phases (Table 2) showed lower amount of pro-eutectoid ferrite in carbon steel 1013A and similar values of pro-eutectoid ferrite in microalloyed steel A913 and 1013B.
According Yalamanchili et al. (2004), the linear density of the grain boundary decreases with increasing grain size, which results in fewer nucleation sites for the deformation, induced dislocations.
With fewer dislocations, the smaller the number of sites anchored on the occurrence of a phenomenon of aging.
This is because a similar amount of pro-eutectoid ferrite and grain size (Table 2).

Furthermore, we show that larger grains in crystalline films are associated with a higher leakage current density.
Samples with larger crystal grains exhibit a higher leakage current.
We assume that the amorphous films or films with a high number of small grains provide much more complex leakage paths compared to films with fewer large grains, subsequently reducing the probability of carrier conduction [14].
Dependence of Jleak on the size of crystalline grains at two different applied fields.
Samples with larger crystal grains exhibit higher Jleak at higher applied voltages.

A number of methods such as sol-gel method [3] and chemical vapor deposition [4] have been reported for deposition of ATO thin film.
In addition, it can be inferred that the density of fluffy particles tends to increase as the number of sparking cycle increases.
The Rrms and Rave roughness of thin films decreased with increasing Sb concentration, this result indicated that the grain size of thin film was increased.
Moreover, the grain size obtained from AFM images are slightly larger than those observed from SEM images, due to the broadening effect of the tip-shape convolution [5].
The size of the crystalline grains and the nature of the grain boundaries have a significant effect on the optical properties.

The measurement of the displacement is additionally used to determine the exact number of cycles per ultrasonic pulse.
Furthermore, twinning in large grains of the primary α-phase and grain refinement were observed in the fatigued specimens.
At first the specimens were loaded for a defined number cycles ΔN1 at a stress σa,1 leading to 1010 cycles or more.
The parameter Nf,TST / Nf,SST which is the quotient of the number of cycles of the second loading step of the TST and the number of cycles of a single step test (SST) at σa,2 is used to evaluate the defects caused at the low stress amplitude σa,1.
A significant influence of ΔN1 at the number of cycles to failure at σa,2 can be observed.

The size of a KMC lattice step has to be much less than the grain size, the grain size has to be much less than the size of a macroscopic finite element and the size of macroscopic elements has to be much less than the characteristic size of the component.
It reduces the necessary memory proportionally to the number of finite elements in the macroscopic mesh.
Modeling of coupled processes at micro-and meso-structural levels In order to predict mesoscopic internal stresses, a macroscopic representative material unit with a high number of grains has been pregenerated and a mesoscopic finite element mesh has been superimposed on the lattice of KMC.
As a result, all grains or particles in the considered macroscopic material unit have been divided into finite elements.
The structure of constitutive laws for the sintering of fine grained materials, Acta Metall., 42(7), 2191 (1994) [6] E.