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Kimura, Mechanical properties of ultra fine grained steels, J.
Tsuzaki, On Annealing Mechanisms Operating in Ultra Fine Grained Alloys, in M.
Also, the characteristic length of dislocation becomes grain size dependent in submicrocrystalline/nanocrystalline materials, i.e. the grain size strengthening should vanish as the grain size decreases down to nanoscale [[] E.
This suggests that the grain size strengthening becomes less effective as the grain size decreases to submicron range.
Acknowledgements The financial support received from the Ministry of Education and Science, Russia, under Grant No. 14.575.21.0003 (ID number RFMEFI58414X0003) is gratefully acknowledged.

Figure 1 (a) is a photograph of the sample sintered at a temperature of 450 ℃, it can be seen , the number of small second phase , the formation of voids at the grain boundaries more loose tissue of the large particles and between the particles the binding force is not high .
Figure 1 (b) is a photograph of the sample sintered at a temperature of 500 ℃, it can be seen, significantly increased the number of the second phase, a continuous distribution on the grain boundaries, but still significant voids phenomenon, which may be due to sintering temperature slightly above the eutectic temperature of the material, there eutectic liquid, appear transient liquid phase sintering, the grain boundary diffusion is not fully, resulting sintered structure is not dense.  
Figure1 (c) photograph of the sample sintered at a temperature of 550 ℃, it can be seen, the second phase the number continues to grow, there is almost no voids exist, the higher the density of the material.
Most La and Al react to form Al11La3 who looks like the needle, in turn, increases dispersion of the grain boundary phase; Needle (Al, Mg) 11 la3 phase forming nucleation first , adsorbs on α- Mg , stopping α- Mg grain's growth due to its pinning effect, and then we get fine grains and reinforced matrix.
This is consistent with strengthening mechanism of refining the grain of the magnesium alloy at room temperature, also can use Hall-Petch formula (1) to explain, namely, grain size, the greater the compressive strength is smaller, the smaller the grain size, grain diameter, the greater the compressive strength

Nanocrystalline materials with high strength have been reported in large numbers.
Additionally, nanocrystalline materials are characterized by a large volume fraction of grain boundaries and triple junctions [1].
When the grain size is reduced to the nanometer range, the dislocation density within the grain is decreased in particular for materials with average grain sizes less than 30nm [2].
This result suggests that fabricated bulk nc-Ni-W had inhomogeneous grain size.
Bulk nc-Ni with a grain size of about 60 nm exhibited an ultimate strength of 1006 MPa and good ductility of 8.8 %. 3.

In the text, SSVs of an orientation x are numbered x1, ..., x4, i.e. the basic variant and three other ones, generated respectively by two-fold axes 2NDL , 2TDL , 2RDL .
Journal Title and Volume Number (to be inserted by the publisher) 3 4 Title of Publication (to be inserted by the publisher) Figure 2b shows a much less typical case of nucleation in a band with the orientation close to the Cube component.
In the foils prepared from ~10%recrystallized material two types of new grains were observed: small, isolated grains and much larger grains formed complex sets of recrystallization twins.
The orientations of small grains - with the area at least 102 times smaller than the area of the largest grain observed - are distributed around the deformation texture components.
Small, isolated grains could be found in the neighborhood of complex recrystallization twin sets. 6 Title of Publication (to be inserted by the publisher) Differences in the size of new grains can be related to the characteristics of orientation relationships between a new grain and the deformed matrix; quite different for small and large grains.

No carbides inside the grains were observed by SEM.
The peak positions of a Fe-Cr, M6C (Fe3W3C) carbides and Fe-C agreed well, respectively with the ICDD card numbers 34-396, 41-1351 and 52-512.
Referring to Fig. 4, brief descriptions of each stage (indicated by number in the Fig.4) are given below: 1.
The primary d ferrite grains nucleated and grew 2.
The difference in nano hardness value of ferrite is due to the intrinsic difference of each grains, dislocation density, work hardened grains in the near surface region and the presence of dispersed fine carbides around the grain boundaries [15].

Over last decade, a number of crystal plasticity modes on HCP materials have been established to study the mechanical behavior of titanium [2].
The finite element model of poly-crystalline titanium is shown in Fig.7, the element number is 13720(7´28´70), each element stands for a grain, and the local coordinate of the element represents the lattice direction of the grain.
Evolution of the grain orientation.
Thus increases the number of grains with loading directions of A, D and E, and yields dark grey regions at the corresponding locations on the inverse pole figure.
Acknowledgements: The present project is supported by the National Nature Science　Foundation of China (project number: 19972065), and Key Laboratory Foundation of ShenZhen University (project number: 4CJB) Reference [1] Asaro, R.J. and Rice, J.R.: J.

In order to determine the number, size and distribution of pores, two rheocasting alloys were investigated using computed tomography (CT).
Number, size and distribution of pores were thus determined using the software package Volume Graphics Studio Max 3.3.
S11)), indicating that a significant grain growth occurs during T6.
The number density is only 0.024 mm-3.
The number density is 0.7 mm-3.

Influence of Plasticizers on the Properties of Fine-Grained Polymer Concrete F.L.
Properties of polymer concrete mainly depend on the content of the binder, the grain composition of the aggregate, type and content of filler and the hardening conditions.
This paper presents the results of studies of the type and quantity of plasticizers on the properties of fine-grained (sand) polymer concrete.
According to the grain composition and content of dust and clay particles sand belongs to the I class, to the medium grain size group, its properties meet the requirements of Russian Standard 8736 [20].
Microcalcite of MK-100 type with grain size up to 100 µm was used as a mineral filler.

The resulting microstructure is mainly formed by very fine grains.
This simple procedure aims to obtain significant grain refinement through a small number of passes with high reduction per pass.
A small number of large grains of approximately 20 om in diameter are embedded in a matrix of small recrystallized grains of approximately 5 om in diameter.
The final average grain size is near 6 om.
Equiaxed grains of average size equal to 8.5 om can be observed.

The solid grains coarsened as deformation temperature increased.
When the number of neurons in each hidden layer exceeds 3, RMSE drops sharply.
As a whole, RMSE decreases with the increase of the number of neurons and the number of hidden layers.
While more hidden layers and number of neurons could reduce computational efficiency.
These deformed grains show preferential orientation.