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High purify, fine grain size, high strength and toughness is the characteristics of it which can get by suitable component and technics design, especially its corrosion resistance is Substantial increased.
Nb or V added in the rail steel is used to refine grain and precipitation strength.Chemical composition and mechanical properties of U68CuCr are shown in Tab.1 and Tab.2.
From the picture, Dispersive precipitations distribute at grain boundaries and ferrite can be found in the photos.
The early corrosion behavior of U75V rail steel is a small amount of the initial coarse pitting,but the U68CuCr shows a large number of relatively uniform distribution of small pitting behavior.
In this sense, the grain size is finer, and grain boundary area will increase, but radius curvature of corrosion pits is larger speedly because of the formation of small pits, this control the development of corrosion pits and corrosion rate is reduced.

Theoretically, the effective strain (e) due to HPT is determined as e =2pNr/√3h, where r is the radial distance from the center, N is the number of turns and h is the disk thickness [2].
Processing a Mg-9% Al alloy leads to a significant increase in hardness up to ~120 Hv and produces a very refined grain structure with average grain size of ~0.15 mm [4].
The present results show this heterogeneity persists after larger number of turns which confirms this is not a transient effect.
Well-defined grains with average size of ~2 mm are observed in the CP-Mg surrounded by ultrafine grains.
Coarser recrystallized grains have been reported in pure magnesium processed by HPT at room temperature [3] and ultrafine grains were observed in a Mg alloy [4].

The research shows that: with the extension of the ball milling time, the number of nailing of Al2O3 particles on the outside of the Al ball is first increased and then decreased.
Raw Materials and Research Experimental The raw materials in the research experiment are the industrial purity Al powder (the average grain diameter for 15um) and the analytically purity Al2O3 powder (the average grain diameter for 500nm), respectively.
It can be shown that the number of pinned A12O3 on the outside of the Al ball showed that the trend is first increased and then decreased as increasing the ball milling speed.
As the sintering temperature is 700 ℃, the bonding strength of the grains in the sample is not large, and most of the grains remain in the grain state before sintering, but some grains combine to form larger grains, and most of the grains have more cracks at the joints. , resulting in a very low density sample. 800 ℃ not only ensures the proper fluidity of aluminum, but also the molten state, and the bonding strength between particles is high, so it is the densest.
Conclusion In this paper, with the extension of the ball milling time, the number of pinning of Al2O3 on the outside of the Al ball firstly increased and then decreased; with the increase of the ball milling speed, the number of pinning of Al2O3 on the outside of the Al ball showed a trend of firstly increasing and then decreasing.

Equal channel angular pressing (ECAP) has attracted a lot of interest due to its ability for fabrication of bulk ultrafine-grained materials.
These techniques are fundamentally different, but they all introduce large plastic strain during deformation to achieve significant grain refinement.
Up to now, a number of FEM simulations have been conducted to help understanding the deformation mechanism of the ECAP process [8-11].
The outer corner gap between the sample and ECAP die decreased obviously when the element number increased from 600 to 2400.
The gap remained similar when the element number was larger than 2400.

The effect of grain size on the martensitic transformations and properties of the alloys is discussed.
The next stages of structure reformation are the anomalous grain growth (Fig. 3 f) and, then, total recrystallization of B2-austenite.
Diagrams of dependence of the critical TMT temperatures of Ti49.5Ni50.5 on the average grain size The diagrams of TMT and grain size effect.
Only from 50–100 nm, pairwise twinned crystallographically equivalent variants of the martensites are formed in grains during the TMT.
The single-packet morphology can be retained in the grains up to micron sizes.

The most detrimental defects in this material seem to be the grain boundaries and impurities dissolved in the matrix.
The measured area always includes some grain boundaries and thus provides a mean value of the recombination in the intra-grain regions and of the extra recombination at the grain boundaries.
In the 100K EBIC map almost all grain boundaries are active.
Furthermore, in some grains extended networks of dislocations are visible.
The financial support of the European Commission through the project FOXY (contract number 019811) is gratefully acknowledged.

The impedance spectrum indicates that Pr-doped sample consists of semiconducting grain and moderately insulating grain boundary regions.
Generally, the formula of doped bismuth titanate is (Bi2O2)2+(Am–1BmO3m+1)2– , where A means mono-, di-, or trivalent ions, or a mixture of them; B means quadri- or quinquevalence ions, such as Ti4+, Nb5+, Ta5+; and m means integer number > 1.
Pr-doped sample exhibits randomly oriented and plate-like grains, of which the average grain area was approximately 5×5μm2, and thickness was less than 2μm in general.
In general, the capacitance C of grain and grain boundary are typically of the order of pFcm–1and nFcm–1, respectively.
The room temperature data therefore indicate BixPryTi3O12 ceramics consist of moderately insulating grain boundary regions with semiconducting grains.

Different ways are used to prepare large grain poly-Si active layers for solar cells [9-12].
It can be seen that triangular prism-shaped grains have grown on Si (111) regions and poly-Si grains grow on SiO2 regions.
The irregular heterogeneous diffraction contrast of the Si film on SiO2 layer indicated that there existed large number of defects in the film.
Triangular prism-shaped grains grown on the regions of Si (111) substrates are single crystals.
Large-grained polycrystalline silicon on glass for thin-film solar cells.

Except the screws, which are parts of complex agricultural machines a great number of screw carriers are being used now for grain transporting [3].
The grain loading kinematics is investigated on the basis of equations of motion in screw conveyer.
Thus, for the barley grain − ∆N = 54%, for technical salt − ∆N = 59%
- when the material movement height h increases from 0.25 to 1.75 m, the torque T increases, and for barley grain DТ is 25%, and for technical salt − DТ = 29%
Investigations concerning the determination of the effect of rotations number n, passage fill factor ψ and passage diameter on the efficiency during grain transportation have been carried out.

Also, the female genotype may modulate the landing of pollen grain and final result of its performance [5].
Table 1 In situ pollen germination of self-pollination between cassava genotype SC5 (♀´♂) Time after pollination (min) Number of in situ pollen grains Number of in situ pollen germination In situ pollen germination rate（%） Reaching position of pollen tube 10 50 0 0.00 20 50 1 2.00 Stigma 30 50 2 4.00 Stigma 40 50 14 28.0 Stigma 50 50 8 32.0 Stigma 60 51 20 39.2 Ovary 120 73 25 34.2 Ovary Table 2 In situ pollen germination of cross-pollination between cassava genotypes SC5(♀) and SC7 (♂) Time after pollination (min) Number of in situ pollen grains Number of in situ pollen germination In situ pollen germination rate（%） Reaching position of pollen tube 10 50 2 4.0 Stigma 20 72 27 31.0 Style 30 323 155 66.8 Ovary 40 136 89 65.4 Ovary 50 152 92 60.5 Ovary 60 247 142 57.5 Ovary 120 154 83 53.9 Ovary The fruit sets of self- and cross-pollination in the present study were investigated and the results were as shown in Table 3.
Additionally, the number of pollen grains on the stigma also affected the GR.
Pollen could not germinate in the water and grains would begin to burst after 20 minutes of soaking.
After 30 minutes, about one third of pollen grains would burst and when the duration exceeded an hour, a majority of pollen grains would burst and lose activity [13].