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Thermal neutrons and high energy X-rays both have a high penetration power for a large number of materials [5].
A subsequent annealing leads to a coarse grained microstructure.
One can see clearly some single grains, which indicates an insufficient number of grains for a texture analysis using the volume method even for a bundle of 10 parallel wire sections.
In figure 4b one can see a much better grain statistics.
Nevertheless the number of grains was still to low for a sufficient result.

Products differ significantly in terms of grain morphology and the degree of defects in structure.
It allows the synthesis of a number of functional materials with nanometric scale, including perovskites [7, 8] without the excessive grain growth, as well as the presence of sinters.
This technique also generates a large number of defects in the crystal lattice through which the products often exhibit different properties, such as optical, catalytic or electric.
SEM images of Ca0.25Cu0.75TiO3: (a) high-temperature treatment, (b) mechanochemical synthesis High-temperature synthesis method results in grain growth (1.5 - 2.5 μm) and sintering of grains giving uneven distribution of particle size (Fig. 2a).
The milling process provides homogeneity in the distribution of grain size (100 – 500 nm) (Fig. 2b).

Fig. 1 Kinetics of austenitic grain growth Kinetics of austenite grain growth.
Austenite grain then coarsens irregularly.
At the temperature of 850°C number of particles is comparable in both steels microstructure.
Generally the monitored grain size is comparable or finer then austenite grain before deformation.
Grain size corresponds to initial austenitic grain before deformation or is smaller.

Aiming at the defects of commonly used methods of gravel size design and the characteristic that the gravel used in field operation is actually a mixture of gravel with multiple grain diameters, this paper builds a model of pore structure in gravel layer through researching the gravel pack structure caused by the gravel of two grain diameters mixed under actual packing conditions, calculates and analyzes the pore sizes in gravel layer.
Ultimately, based on Saucier method, this paper presents a new gravel size optimization idea for gravel packing sand control with multiple grain diameters mixed, which agrees with the actual situation of industrial gravel, and gives the idea’s computing method.
Model Building and Analysis of the Precision of Sand Blocking To facilitate the analysis, it is assumed that the gravel used for packing consists of two kinds of gravel with two different diameters and the same density, the ratio of grain number is 1:1, and the distribution after packing is uniform and compact, the two dimensional drawing of its possible arrangement pattern is showed in Fig.1.
Through calculation we get the equations as follow: （1） Where, Dmax is the grain diameter of bigger gravel, Dmin is the grain diameter of smaller gravel, dA、dB、dC、dD are the equivalent diameters of four different arrangement patterns, d´ is the average grain diameter of formation sand, and there are always d´＞dD.
The SPE paper of number 8428 has mentioned that the uniformity of formation sand have important impact on the sand control effect of gravel packed well.

Because the size of the slab grain size decides the grain size of hot rolling plate, the grain of A group is bigger than that of B group after hot rolling.
There are no differences in the grain size of the finished product.
In the same continuous annealing process, the degree of grain breaking is recovery, recrystallization and grain growth process again, so the final grain size is the same.
Because of the cold rolling process, a large number of shear zones are formed, the larger the grain size, the higher the shear zone distribution.
Since the shear zone can be highly stored, the recrystallization grains occur preferentially in the shear zone and the nucleation of the grains in the shear zone.

One can observe that heterogeneity in the mechanical properties generally tends to decrease with the number of ECAP passes.
Dependency of mechanical properties of titanium VT1-0 on the number of ECAP passes Variation of the mechanical properties with the number of ECAP passes (Fig. 2) corresponds to the classical pattern, i.e. with the number of passes, strength properties tend to increase, and plastic properties, to decrease.
For both of the ECAP routes, heterogeneity decreases with the number of passes.
References [1] Beyerlein I.J., Li S., Alexander D.J., Necker C.T., Tome C.N. and Bourke M.A., "Heterogeneity in Texture Development in Single Pass Equal Channel Extrusion", Ultrafine Grained Materials III, ed.
"Sample Size Effect on the Mechanical Behaviors of UFG Ti-6Al-4V Alloy", Ultrafine Grained Materials III, ed.

The amount of strain estimated from Eq.1 (which obtained from the count of rotational number at each temperature) is described in Table 2.
While, a very small amount of the new fine crystal grains are observed along the original crystal grain boundary due to dynamic recrystallization during warm working [2].
Very fine crystal grain along the grain boundary was able to be confirmed in each microstructures.
When working temperature at 473K or more, the deformation twins cannot be seen and very small new fine crystal grains are observed along the original crystal grain boundary due to dynamic recrystallization.
The amount of small fine crystal grains increase with increase of working temperature.

Fig 1 illustrates that the grain size increases with elevating the deposition temperature.
It indicates that the GBs of above-mentioned samples contain a large number of amorphous phases (a-phases).
By the above analysis of SEM and XRD, it is considered that there are large numbers of a-phases at GBs.
Fig. 2 XRD patterns of polysilicon nanofilms with different deposition temperatures Fig. 3 Interstitial-vacancy model of amorphous phase at grain boundaries In our model, each IV pair can be characterized by the number of neighboring IV pairs (defined as IV pair coordination number).
An IV pair can recombine after capturing enough energy, and the recombination rate increases as the number of neighboring IV pairs (the coordination number) decreases.

The grain size was measured using Image Pro Plus® software.
This sample shows both well-delineated and undefined grains.
The recrystallized grain sizes grow exponentially, but remain small, i.e., ~3 mm, even after 7200 s of annealing at 700ºC; most of the grains have a high-angle grain-boundary, as shown in Fig. 4(d).
Mean austenite grain size as a function of Fig. 7.
Acknowledgments The authors thank FAPEMIG (process number TEC PPM-00373/11), CNPq (process number 471128/2011-2), and CAPES (scholarship of SSFD) for the financial support of this research.

The corrosion of these refractories were investigated in a number of studies [6-9].
Backscattered electron imaging (BSE) was primarily used for SEM examination of polished specimens due to the ability to separate different phases based on the atomic number contrasts [4].
Exsolved spinel was widely observed within the periclase grains but the grain boundary phases of periclase grains will not be reported here for the sake of brevity.
Selected spots along a line extending from the center area to the rim are numbered 1-4 in Figure 2a.
M: magnesia grain, Cr:chromite grain.