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Fibrous tissue is caused by severe plastic deformation (SPD), long strip grains tell us that regional plastic deformation occurs, but a large number of equiaxed grains are still located in the inner of specimen mainly, which is in stage of rapid elastic deformation yet.
We can see that a large number of small grains appear nearby fibrous tissue, which should be recrystallization structure.
The large number of long strip grains in Figure 5(d) confirms that the second outer layer of rotating band is still subject to large compressive stress.
(a) Long strip grain in second outer layer of specimen (b) Equiaxed grain in inner layer of specimen Figure 6.
It was reflected as macroscopic plastic deformation and increasing of hardness, while in the micro scale there were a large number of dislocation and dislocation tangles.

, (4) where, and are constants, (μm) the grain size of DRX, (μm) the average grain size, and (μm) is the initial grain size.
Additionally, lower dislocation density and distortion energy with smaller deformation and lower temperature leads to a lower number of nucleation on the blade rabbet (Point 1) and damper platform (Point 4).
The finer grain lies in the point 7 and the grain sizes are about 2.5(μm) after finish forging.
It can be seen that the grain in the blade is finer and uniform and the grain degree is up to 11.
The grain size number of DRX in the middle of blade body is 9~10 and the grain size number in the leading and back edge of blade body is 12~13.

With an increase of deposition time, the Sn/S atomic ratio and grain size and the number of crystallites in the layers increased while the dislocation density and bulk resistivity decreased.
Fig. 2(b) gives the variation of the number of crystallites, CA with the deposition time.
This could be due to an improvement in the crystallinity of the layers corresponding to larger grain sizes thereby decreasing the grain boundaries and consequently a decrease in the dislocation density.
Fig. 2: Change of (a) crystallite size and (b) number of crystallites and dislocation density with deposition time.
The increasing the deposition time could increase the crystallite size and the number of crystallites whereas the dislocation density and the bulk resistivity decreased.

There are some recrystallized grains mixed in coarse deformed grains.
At 400°C, a large number of small recrystal grains generate in deformation structure, most of them are round and of uniform distribution.
The average grain size increases as strain rate bigger than 1s-1, at higher strain rate, the number of recrystallization grains is smaller for some deformed grains have not triggered recrystallization.
Thus increasing the number of dislocation sources per unit volume in a grain, aggravating the trend of dislocation tangle simultaneously.
The growth of recrystallization grains is finished by combining the grains.

Fig. 2 is the relationship of elongation versus the number of ECAP pass.
The curve of elongation versus the numbers of ECAP passes.
It can be seen that after conventional extrusion the alloy has coarse grains and there are a lot of precipitates on grain boundaries and only a few in grains.
It can be seen that the ZK40 processed by 1 pass has the largest number of precipitates, and the number of precipitates of ZK40 processed by 4 passes is smallest.
Because the precipitates in the microstructure hinder grain boundary sliding, the ZK40 processed by 1 pass with the largest number of precipitates shows greatest flow stress in the three conditions.

A specific single crystalline XRD method is applied on these two non-cubic phases to determine the local residual stresses in two grains on each side of a grain boundary.
Introduction Previous works over the last decade showed that a number of cast microstructure features inherently relate to the solidification path of TiAl-based (γ) alloys [1].
This new method is available for any crystalline symmetry and is applied, in this paper, to two coarse lamellar grains and adjacent lamellar grains to obtain stresses tensor in each phase and in both grains.
Optical microscopy reveals a microstructure composed of two phase γ+α2 lamellar grains with serrated grain boundaries (Fig. 1).
We can see in Figure 5 a number of spots coming from the grains in the nearby, and from γ lamellae of the grain with one of the 5 other orientations of the same grain.

The emission Mössbauer spectroscopy expands the number of subjects and physical phenomena which can be studied.
NGR spectroscopy of grain boundaries in coarse-grained materials The capabilities of Mössbauer spectroscopy for grain boundary studies are analyzed in [6].
If the grain boundary width is 0.5 nm, one can easily determine that for grains the size of 10 mm the volume fraction of grain boundaries is 0.00015.
To get reliable information on the atomic and magnetic structure of a whole interface layer of Fe/Cr superlattices, in a number of studies Fe layers were formed completely of 57Fe atoms [42]-[45].
The hyperfine field functions in this case are represented as superposition of separate peaks corresponding to various numbers of Cr atoms in the nearest and next neighborhood of 57Fe atoms.

It is well known that ultrafine-grained materials often possess superior mechanical properties to those of their conventional coarse-grained polycrystalline counterparts[1-3].
Also several methods for grain-refinement have been developed, few of them can be used in the grain-refinement of pipeline steels.
In this paper, ECP method was applied to X70 steels to refine its grains and improve its mechanical behavior; the mechanism of grain-refinement was also discussed.
In combination with a very short treating time, the newly recrystallized grains have not enough time to grow, and then smaller grains can be obtained finally.
As a result, large numbers of small γ-phase nuclei can be generated in the original α-phase during the heating process in ECP treatment.

Ultrafine-Grain Structures produced by Severe Deformation Processing P.
Keywords: Severe deformation, Aluminium alloys, Ultrafine grains, EBSD.
Introduction Ultra-fine grained materials offer significant advantages in terms of high strain rate superplasticity and improved mechanical properties, compared to materials with conventional grain sizes [1].
However, in practice, the batch nature of the process, the high number of cycles required to develop a fine grain microstructure, and the forces required to deform large diameter billets, mean that the process is likely to remain laboratory-based.
For example, fine dispersoids required for grain size stability during superplastic forming inhibit grain refinem ent.

Specimens with different grain dimensions, grain shapes, α/β phase ratios, densities were obtained by changing the heating rate and dwell time of SPS.
Both equiaxed and columnar β- Si3N4 grains are formed during sintering, but the thermal conductivity of Si3N4 ceramics is affected only by columnar grains.
Table 1 shows the statistic of equiaxed grains and columnar grains formed with different sintering conditions.
Considering the effects of the average diameter (Φ) and the number per area (N) of the columnar grains together, Fig. 5 shows the relationship of Φ×N and thermal conductivity of SPS sample.
Fig. 5 Relationship of Φ×N and thermal conductivity of SPS sample Table 1 Statistic of equiaxed grains and columnar grains formed with different sintering conditions Heating rate [K�s-1] Dwell time [min] Φe [µm] Φc [µm] Nc [µm-2] 2.5 2 0.46 0.16 0.06 2.5 5 0.49 0.21 0.17 5 2 0.41 0.20 0.21 5 5 0.45 0.44 0.24 Φe: Average diameter of the equiaxed grains; Φc: Average diameter of the columnar grains; Nc: Number of the columnar grains per area.