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As the annealing proceeds, the number and sizes of these nuclei increase until they form a continuous layer, through which the new portions of Sn diffuse from the bronze matrix into Nb filaments.
From three regimes of the diffusion annealing (А, G and H), which resulted in the highest critical current, the greatest number of filaments with the residual Nb are present after the one-staged low-temperature annealing in spite of the long holding (Fig. 3, regime A).
A number of other regimes were tested for the improvement of the nanocrystalline structure of superconducting phase and the enhancement of the critical current (see Table 1).
The grain size scattering increased markedly both within one filament and between sections of different filaments, the average grain size increased as well and some grains the sizes of up to 300-350 nm appeared.
Critical currents of the wires with ring Nb filaments annealed by various regimes versus average grain sizes of superconducting Nb3Sn phase Thus, the analysis of structure and morphology of superconducting Nb3Sn layers in composites with ring filaments, based on TEM and SEM data, has shown that the critical current of the superconductors is affected by a number of factors, such as the completeness of Nb filaments transformation into Nb3Sn (the residual Nb amount), morphology of superconducting layers (the presence or absence of columnar grains), average grain sizes of Nb3Sn and grain size scattering.

In contrast SPDprocessed materials possess a granular structure containing a significant number of high angle grain boundaries [2, 3].
Within a various number of different SPD-techniques [2] the most utilized are Equal Channel Angular Extrusion (ECAE) and High Pressure Torsion (HPT).
The smallest grains have a diameter of ~30 nm that is well in the nanocrystalline range [2].
The SAED shows concentrations suggesting the coexistence of low- and high-angle grain boundaries.
According to the comprehensive results in [18] the SRS of bcc metals decreases with a reduction of grain size, since new grain boundaries act as long-range obstacles that can not be overcome by thermal activation.

While desired applications of ceramics and their composites are mainly at high temperatures, very few numbers of investigations have been focused on high temperature mechanical properties and creep response of CNT-reinforced ceramics, so far[4-6].
Since grain boundary sliding has been accepted as the most important mechanism for high temperature ceramics plastic deformation, the grain boundaries nature has a vital role on the deformation behavior of polycrystalline ceramics [7].
Well-dispersed CNTs among the ultrafine 3Y-TZP grains with size of about 100 nm are observed.
(1) where G is the shear modulus and d the grain size.
In the model, Kjun represents the restoring force due to the elasticity of the adjacent grains, and the dashpot of viscosity h represents the amorphous layer between the grains.

Number 3 (m=0.3, T=750℃ V=0.5 mm/sec) shows the maximum load of the Z-axis.
Number 1 (m=0.1, T=750℃, V=0.5mm/sec) shows the maximum effective strain.
Number 2 (m=0.2, T=750℃, V=0.5mm/sec) shows the maximum effective stress.
The increasing temperature reduces effective stress from Number 3, 4, and 5.
Figure 9(b) shows the simulation of the grain boundaries, dislocation density, grain orientation, and grain orientation and grain boundaries simulation of Fig. 9. p1, p2, and p3 of the average grain size were 2.24642, 2.37440, and 2.18039 mm2/mm3, respectively, and p3 produced more detailed grain via the simulation.

The workpiece and abrasive grain are assumed to consist of monocrystalline Si and diamond, respectively.
If the number of neighbors (�n) is four, the specific Si atom takes the diamond structure.
Fig. 7 shows the time variation of number of workpiece atoms in amorphous state. 0 20 40 60 80 100 120 0 20 40 60 80 100 120 Number of atoms in amorphous state Time ps (b) Chemo-mechanical grinding (CMG) (a) Diamond grinding Fig. 7 Variation of number of workpiece atoms in amorphous state 2 nm (a) Diamond grinding (b) Chemo-mechanical grinding (CMG) 0 Traveling distance 0.1 nm Fig. 5 Cross sectional view of scratch groove at solid lines shown in Fig. 4, where broken line shows contour of abrasive grain in initial condition.
r1 r2 R 2 21 rr R + = (Si: R = 0.3095 nm) :n� :4 :4 > = n n � � Diamond structure Amorphous state Number of atoms within R Fig. 6 Index for crystallinity of silicon The stress caused by Si-C interaction is relatively small for all the cases shown here, because the abrasive grain size and cutting depth is very small.
According to Fig. 7, it is easily understood that the deformation volume or the number of atoms in amorphous phase becomes larger in diamond grinding than that in CMG.

Deformation structure evolution and grain refinement.
Black lines represent high angle grain boundaries (>15 o) and white lines low angle grain boundaries (2-15 o ).
After 8 CFAE passes (εvm ~ 5.3) the average spacing of HABs, or grain width, was at a submicron scale and in the most regions groups of pancake-like submicorn grains were seen to have formed within the lamellar structure.
Following deformation, crystallographic textures of samples processed to different numbers of CFAE passes were determined by EBSD.
CFAE processing of AA1050 sheet samples was successfully carried out to various total numbers of passes and a uniform and nearly equaixed UFG structure was achieved after 10 CFAE cycles, or at an equivalent strain of 6.6.

Acetic picral solution was used for grain boundary etching.
The grains are not completely recrystallized and a high amount of low angle grain boundaries was detected.
With increasing number of ARB passes, the grain size decreases no more (see Fig. 4).
With increasing number of ARB passes, the intensity of basal texture rises.
Compressive yield strength (YS) and the maximum strength (σmax) dependence on number of ARB passes.

With increasing number of passes the mean grain size reduces by a factor of about four (Fig. 3a).
(thick lines: high angel grain boundaries; thin lines: low angel grain boundaries) (a) (b) Figure 3: Grain parameters obtained by EBSD grain reconstruction: (a) mean grain size and (b) mean aspect ratio determined from individual grains. 354 Texture.
(a) (b) Figure 5: (a) Deviation in ϕ1 from the ideal cube component and (b) texture strength with the number of passes In general, during ECAP the grains are sheared and thus become elongated.
The inclination of the grain long axis with the extrusion direction decreases with increasing number of passes.
The increase in inclination with increasing number of passes is correlated with the texture obliquity and grain refinement.

Summary results from field UT in the Río Papaloapan Bridge Structural deficiency Number of anchorage elements Type of element Large Grain Size (ASTM 2) 8 2 High Pore Content 2 1 and 3 Probable large Grain Size 6 2 Once the structural deficient elements were identified, a rehabilitation project was proposed to replace these elements and an integrity analysis was required to evaluate the structural reliability of the remaining elements, considering the statistical characterization of their microstructural, mechanical and chemical properties.
Characteristics of the removed anchorage elements Id number for anchorage element Anchorage element type Semi-Harp Cable Deficiency 1 2 1 13 Large grain size 2 2 2 12 Large grain size 3 2 2 13 Large grain size 4 2 3 10 Probable large grain size 5 2 3 11 Large grain size 6 2 3 12 Probable large grain size 7 2 4 8 Probable large grain size 8 2 5 10 Probable large grain size 9 3 6 3 High pore content 10 2 6 13 Large grain size 11 1 7 1 High pore content 12 2 7 8 Large grain size 13 2 7 9 Probable large grain size 14 2 7 10 Large grain size 15 2 7 12 Large grain size 16 2 7 13 Probable large grain size 17 2 1 6 Good condition 18 3 2 4 Good condition 19 2 5 5 Good condition 20 1 6 1 Good condition Table 4.
No. 5 Large grain size (b) Element Id.
No. 19 Fine grain size Figure 11.
The element that was initially classified as large grain size and resulted with a fine grain size with a large number of pores, was incorrectly classified because of the pore content, where ultrasonic energy dissipation presents almost the same behavior.

Experiment results show thin parallel shear bands with a width of 0.3~0.4μm are generated after one ECAP pass, which are composed of large number of dislocation cell blocks.
However, application of pure titanium with coarse-grained microstructure is usually limited by its low strength and thus development of fine-grained titanium is desirable.
But there is a considerable difficulty in applying ECAP to commercial purity titanium (CP-Ti) where the number of active slip system is limited.
Optical micrograph of CP-Ti after a single pass(a-c) and the second pass(d-f): (a)(d)X plane, (b)(e) Y plane, (c)(f)Z plane addition, the grains in X plane and Z plane were refined, the microstructure remained equiaxed and a large number of twins in grains may be found (Fig. 1a, Fig. 1c).
During the second ECAP pass, the grain structure is significantly finer than that of the first pass.