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Compared with traditional metal processes, ECAP has a number of advantages such as introducing exceptional high strain without changing the cross section of workpiece.
Annealed at the lower temperature 923 K, the primary α grains were different in size and not well globularized (Fig. 3b).
While annealed at the higher temperature 1073 K (Fig. 3e), the equiaxed α grains showed pronounced growth.
It attributed to the increase in number of grain boundaries, which balanced the decrease in density of dislocations due to annealing softening.
Increasing energy input introduced by longer annealing time led to more complete recovery and recrystallization, and longer annealing time caused grain growth and consequent decrease in number of grain boundaries.

The determination of time-dependent grain shape and grain size (i.e. grain coarsening), as well as coordination number distribution is presently the most challenging task in the application of solid skeleton (network) models for predicting the mass transport during LPS.
In analysis of 2-D grain coordination number (connectivity) against the measured distortion for various alloys it was found that the critical connectivity required to maintain structural rigidity was 2 and 3 in gravity and gravity environment, respectively [60,61].
As the 3-D nearest neighbors search algorithm we will apply simple method for computation of nearest neighbors ordinal numbers vector.
After 120 min (Fig. 12(b)) the number of skeletons was slightly increased to 6 skeletons with 8 bonds.
Although the number of solid grain contacts after 180 min (Fig. 12(c)) is greater than after 120 min, it can be seen that even after long sintering time the skeletal strength is reduced.

Results To analyze the grain size of the Samotlor field, the results of grain size distribution for thin sections were used that had been obtained by Nizhnevartovskgaz OJSC specialists and processed at TSGE OJSC by a group of scientists headed by S.B.
The number of wells where studies were undertaken is obviously insufficient for correct the summary interpretation of analysis results.
According to descriptions of thin sections, rocks primarily belong to fine-grained sandstones and large and medium-grained siltites.
In terms of the medium size, as noted above, the sediments under study belong to small-grain sand stones and large and medium-grained siltites, which can be related to low energetic capabilities of the transported medium or to the nature of the distributive province.
A large number of stripes of dynamically related subzones must be checked.

Strain of Grains.
The total number of grains used for the measurement was about 240.
Grain Rotation in Oyz-plane.
Grain rotation is mainly produced by inhomogeneous deformation around a grain.
Fig. 15(a) shows measuring principle of strain inside a grain, where the measuring position is shown with the grain number 2 in Fig. 13.

This image includes qualitatively the crystalline information between polycrystalline grains.
This analysis shows that most grains have the texture of [111] direction normal to films, and a few of grains are oriented in the other directions.
The size of a- or b-axis oriented grains are relatively small, compared to caxis oriented grains, which are imaged in Fig. 1(b) by blue color as indicated by 1, 2, and 3 numbers in Fig. 1(b), and which are also localized in larger area than other grains. θ-2θ x-ray scans were performed to compare the nanoscopic orientations of Fig. 1 with macroscopic polycrystalline orientations (Fig. 3) of BLT films on Pt electrodes.
Ferroelectric domains of c-axis orientated grains, which are indicated by 1, 2, and 3 numbers in Fig. 5(a) and (b), respectively, show no changes in the phase image as shown in Fig. 5(b), even after applied voltage of 10V.
C-axis oriented grains with plate-like morphology show almost linear dielectric behavior.

It is proposed that LVECP treatment created a new dynamic factor for nucleation so that the number of nuclei increased, which restrained the formation of large primary α-Mg dendrites and created a base to form spherical crystals of primary α-Mg.
It is more intriguing to see that the grains are globular or non-dendritic in shape.
The function of LVECP discharge in this case is to alter or accelerate the melting at the root and to carry the dendrite arm away from its “mother grain” to where it can grow as a new grain, therefore, the primary α-Mg phase was refined greatly and the non-dendritic primary grains were formed.
The primary phase grains will become coarser, because the nucleus reduces.
With appropriate processing parameters of LVECP treatment, the semi-solid microstructures of AZ91D alloy were modified and the equiaxed, nondendritic grains are formed instead of large grains with dendrites

A comparison between the grain structures shown in Figs. 3(a) and 3(b) indicates that the growth speed might be quite different for each recrystallised grain depending on the interface mobility and the stored energy.
After the recrystallisation grains become equi-axed again in Fig. 3(c).
In (b) recrystallised grains are highlighted by different colours and deformed grains in white with grain boundaries shown using black lines.
Recrystallisation nucleation sites were selected using the criterion: relatively high cumulative number of slip system activated during the previous deformation.
Resutls showed that it is possible to simulate the typical recrystallisation textures experimentally observed for rolled FCC and BCC metals using this nucleation criterion by choosing appropriate critical values although the number of possible slip systems for the FCC metal and the method of calculating the number of activated slip systems in this work are different to the ones used in literature.

One way to estimate the number of diffracting grains on the detector is from Poisson statistics, as demonstrated by [9].
If one assumes the grains in the gauge volume are Poisson-distributed, then one can estimate the actual number of reflecting grains NDG detected on the detector from Eq. 2, where u(I) is the actual standard deviation of the integrated intensity
The measurement results lie on the grain size statistics curve towards the left (with decreasing number of detected diffracting grains) and towards the right on whichever average fitting uncertainty (with increasing number of detected diffracting grains).
The advantage of having an automated primary slit system is that one can quickly find the best compromise to achieve having an optimal number of detected diffracting grains.
Number of detected grains on the detector versus the 2θ uncertainty.

It is found that the plastic deformation occurred unevenly and limited in single grains, shown by micro extruding steps at grain boundaries.
Some long twinning bands curved to accommodate the strain at grain boundaries.
It is seen that by the progress of the plastic deformation the clash between grain boundaries and twinning bands happened frequently, and the micro cracks initiated at such sites, some of them propagate along the grain boundaries or/and boundaries of twinning bands.
(4) In a lot of areas all grain boundaries pushed out, and some interfaces of twinning bands pushed out, too. (5) New micro cracks nucleated from very early plastic period, i.e., the number of the micro cracks increased with the deformation.
Micro cracks form in the intersections of grain boundaries and twinning bands, and of twinning bands.

Fig.2 Typical Raman scattering spectra of Zirconia a)Tetragonal Zirconia, b)Transformed Zirconia (tetragonal + monoclinic) a) b) 800 600 400 200 Wave number (cm -1 ) Intensity (a.u.)
a) b) 800 600 400 200 Wave number (cm -1 ) Intensity (a.u.)
Figure 4 shows the measured relationship between grain size and monoclinic fraction after 150 hrs acceleration test.
Grain size ranged only from 0.2 to 0.3 µm.
Phase stability greatly improved with reducing grain size beyond a threshold value.