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Such materials possess an inhomogeneous microstructure especially after a small number of ECAP passes which makes it necessary to use a high-resolution 3D method for microstructure characterization.
All voxels that form one grain have a misorientation below 5°.
The optimal number of voxels for defining a grain is selected ten.
Misalignment of the sections can cause small grains, which do not actually exist, to be included when less than ten voxels are considered while more than ten voxels would cause small grains which are typical for ultra fine grained material to be excluded.
The true grain volume was calculated by Vgrain=Nv.Vvoxel (2) where Nv is the number of voxels and Vvoxel is the Volume of voxel.

The size of the ferrite grain was 20-80 µm, the shape of the grains was polygonal.
In Fig. 2 and Fig. 3 they are indicated by numbers: 1 - evaporation crater; 2 - transition zone (zone of melting, phase transformations and quenching); 3 - heat-affected zone (zone of the original structure with various elements of grain boundary slippage - GBS).
Their schematic representation is shown in Fig. 2b, where they are designated by number 1 (shear bands, designated by number 2, were not observed in ARMCO pure iron, since they are characteristic, first of all, of fcc-metals).
In the above illustrations, the grain rotation can be observed in Fig. 3 c (grain B, at all boundaries of which accommodation zones are visible, as a result of which the grain acquires new outlines).
In Fig. 3 c, in the grain with the number 3 there are two boundaries, shown by arrows, which differ from all those described above in that they cannot be attributed to the boundaries that have undergone GBS.

After 4 passes the grain size was reduced to ~200 nm, and in this range twins are mainly nucleated at the grain boundaries [14].
The larger the number of ECAP passes, the faster the hardness reduction for 4N5 purity samples (see Fig. 2c).
Microhardness as a function of storage time for 4N5 (c) and 4N (d) purity samples processed by different numbers of ECAP passes.
(a) DSC thermograms obtained at a heating rate of 10 K/min for 4N5 and 4N purity Ag processed by different numbers of passes.
As in UFG microstructures twins mainly form at grain-boundaries, the impurity segregation in the boundaries yielded lower twin boundary frequency in 4N purity samples compared to 4N5 purity counterparts for large number of ECAP passes. 2.

The longer the slope , the more the amounts of grain become,and the smaller size of grain get to be.
Great shear stress will be developed with the flow of melt under the action of violent vibration in the process of grain growth, which will break dendrite arm or grain of dendritic crystal, the broken grains become new nucleus of grain growth, which result in increase of amounts of grain.
It shows vibration can improve the alloy microstructure significantly, increase the grains in the number, decrease its size, spheroidize the microstructure which is better than those without vibration.
Conclusion (1) The longer the casting slope is, greater alloy grains in number is; smaller, more rounded shape and uniform two-dimensional grain size is
(2) Vibration can improve the alloy microstructure significantly, increase the grains in the number, decrease its size, spheroidize the microstructure.

The influence of the variation of different parameters on calculated grain structure is shown.
They determine the number of possible generated nucleuses in the surface and bulk areas.
Increasing the range of ∆Tmax parameter for the bulk the distribution range is wide and the numbers of new grains drastically arise.
The smaller values of surface nucleation parameters as well as the thickness of surface area bring smaller number of grains generated at the borders and finally thinner chill zone.
It results in a smaller central zone, because a lower number of grains arose.

Since superplasticity is a grain size dependent phenomenon.
Over the past decades, there have been a number of attempts to reduce grain size of the materials to submicron- or nano- level so as to achieve high strain rate superplasticity and/or low temperature superplasticity.
The nickel grains mostly remained in equiaxed shape.
During the deformation grain boundary sliding takes place between nickel grains.
When heated to high temperature, the significant sulfur segregation at grain boundaries occured and reduced the strength of Ni-Ni bonds, the effect of which is to inhibit grain growth and to enhance grain boundary sliding.

The microstructure of 0°specimen are of equiaxed grain due to dynamic recrystallization after compression, while the grain shape of 45°and 90°specimens are still of lamellar grain structure.
Therefore, the dislocations concentrated near the grain boundary.
The propagation of dislocations to the matrix is easiest when the maximum shear stress in grain is parallel to longitudinal grain boundaries by applying the external stress in the 45° direction of elongated grain structure.
This could be attributed to the lamellar grain structures and the texture of the extruded bar. 2 The microstructure of 0°specimen are of equiaxed grain due to dynamic recrystallization after compression, while the grain shape of 45°and 90°specimens are still of lamellar grain structure.
Acknowledgements It is a project supported by natural science foundation of shanxi province China (project number: 2009011028-1; 2011011021-1).

Control of the prior austenite grain size by the dispersion of inclusions has been optimized only by experiments thus far, and no quantitative analysis has been offered on the effects of the kind, number and size of the dispersed particles for pinning austenite grains.
The two lattices are superposed, so that each FD cell contains the same number of MC cells.
The correlation between MCS and real time is defined in each FD cell by its temperature, and thereby the number of MC steps in a given FD time increment is given to each FD cell, while the correlation is the same throughout the FD cell of interest.
Grain size D during grain growth simulation using MC !!
The grain growth near the fusion boundary simulated well in the model result and the decrease in grain size with increasing distance from the fusion boundary as well, although the twins in austenite grains seen in Fig. 3(a) makes it rather difficult to compare the exact grain size between the two figures.

Insect infestation is a common problem for stored grain.
Its application to grain with the aim of detecting insect infestation is gaining popularity [11-13].
Different from the BP neural network whose structure has to be artificially designed, SVM automatically determines the required number of hidden units (the number of support vectors, SV).
Experiments and Result Grain samples .
The first group of grain was 2kg un-infested wheat, labeled Sample0.

Important grain size dispersal was observed and a heat treatment was successfully applied on sheets to diminish the grain size and improve the superplasticity of the sheets. 1.
Consequently an investigation with optical microscope was done in agreement with the French specification NF A 04-503 and revealed a non conformity in the grain size : the indicator of the grain size was 8.5, which means that grains were bigger as the maximum size specified.
However grain size is a key characteristic for superplasticity and the cavitation effect is delayed with smaller grains for superplastic forming of aluminum alloys.
The grain size testing is specified as a periodic test – 2.
Results from average grain size computation on non treated and heat treated samples Sample Longitudinal direction Normal direction Non treated Average grain size 24.5 µm 11.9 µm Number of measurements 136 338 Heat treated Average grain size 16.5 µm 8.5 µm Number of measurements 214 523 About superplasticity improvement of aluminum 7475-T4 after heat treatment As the applied heat treatment resulted in a significant grain refinement, we investigated the impact of this refinement on the aluminum 7475-T4 superplasticity with a tensile test.