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Meanwhile, grains bridging and pull-out mechanisms can be found in Fig. 1(b).
All materials consist chiefly of elongated β-Si3N4 grains.
TEM observations show that the TiC particles can be found both inside the grain and on the grain boundaries.
Fig. 2: SEM micrograph of etched surface Fig. 3: TEM micrograph of nanocomposite At some of the grain boundaries and multiple grain junctions, an intergranular phase is observed.
For flank wear, there are not only a large number of ploughed grooves of different depths, but also a small amount of adhesives on the flank face (Fig.4c2).

Average grain sizes of the matrix phases of the alloys were about 20 nm.
Yield strength of those alloys is higher than that of coarse-grained Fe3Al.
The black spots in bright-field image are nanocrystalline grains.
The average grain size of the alloys with 5, 10 and 15 wt. % Ni can be estimated to be about 19, 20 and 21nm respectively in agreement with the XRD results, which come from the grain size distribution determined from a number of different dark-field image taken at different locations.
Fe-Al-Ni ternary phase diagram Conclusions The matrix of the alloys with 5, 10 wt.% Ni consisted of nanocrystalline grains, while the matrix of the alloys with 15 wt.% Ni consisted of nanocrystalline grains and Fe3AlCx phase.

As shown in the Figure, the adding Mo steel significantly improved hardenability, inhibited the generation of the polygonal ferrite and pearlite, and promoted the generation of the ferrite or bainite which have a large number of dislocation distribution within the grains in the moderate and lower temperature area (such as area B in Figure 1).
Fig.1 Dynamic CCT curve of steel containing no Mo Fig.2 Dynamic CCT curve of steel containing Mo 2 Analysis of test results For like 700 MPa to precipitate as the main means of strengthening of steel, the improvement of the matrix strength not only comes from dislocation strengthening and fine grain strengthening, but also from the matrix distribution a large number of dislocation in promoting precipitation on dislocations, and this intragranular dislocations on the precipitation strengthening effect is much larger than the grain boundary.
The containing Mo steel has a relatively more large number of non-polygonal ferrite organizations.
When coiling temperature continues to reduce to 543℃, for the excluding Mo steel, there has a large number of non-polygonal ferrite, the strength is enhanced 70 MPa due to dislocation strengthening and precipitation strengthening effect of strengthened.
Therefore, even adding a small amount of Mo also has a strong strengthens effect. 3 Conclusions （1）The adding Mo steel significantly improved hardenability, inhibited the generation of the polygonal ferrite and pearlite, and promoted the generation of the ferrite or bainite which have a large number of dislocation distribution within the grains in the moderate and lower temperature area

The region of lower hardness near the upper surface disappears with increasing numbers of passes but near the bottom surface the lower hardness remains even after 6 passes.
Since processing by ECAP leads to a very significant grain refinement, the strength of the material after pressing is increased substantially by comparison with the unpressed material.
Each billet was processed through a selected number of passes using processing route BC in which the billet is rotated about the longitudinal axis by 90° in the same sense between each pass [12].
Nevertheless, it is concluded that good homogeneity is generally attained in processing by ECAP provided the pressings are continued through a sufficient number of passes.
Zi, in: Ultrafine Grained Materials II, edited by Y.T.

Analysis of the technological factors that allow acquiring fine-grained structure as well as high physical and mechanical properties of alumina-zirconia ceramics is presented in the paper.
The present paper focuses on the analysis of the technological factors providing the fine-grained structure as well as high physical and mechanical properties of alumina-zirconia ceramics.
To determine the size of the crystal grains, metallographic sections were made.
The sizes of the grains for the ceramics sintered at 1500 °C and 1700 °C are slightly different and do not exceed 1 µm.
In all the cases the ceramics structure is characterized by a big number of pores of different size ranging from several to hundreds of micrometers.

Grain is regular convex polyhedron because of thermodynamic and kinetic reasons in the sintering process, and the average number of faces between12 to 14, which looks very similar to Laguerre diagram.
And construct the right to ball size Laguerre diagram may be different, can be used to simulated grain powder particles before sintering conditions.
Laguerre graph algorithm simulation specific steps are as follows: Step 1: Enter the user parameters, user parameters include: construction Laguerre diagram side the region of space (x direction length, y direction of the length, z the direction of length), the right to ball construction Laguerre diagram average size μ, the coefficient of variation c, whether to allow intersection between the right to ball option (y / n), the required number of Laguerre unit N, the number of grains that is required.
To ellipsoid short fiber reinforced composite material, for example, short-fiber reinforced composite material microstructure is defined as including not only the geometry of an arbitrary polyhedral grains with grain size, but also contains the spatial distribution of short fibers of different elliptical and its crystal orientation.
These two programs will receive orientation distribution and handling of grain reserve ProDesign software visual interface properties can achieve the second phase crystal orientation of the visualization.

High pressure torsion, HPT, is an interesting SPD technique, which, in addition to grain refining, can be used to consolidate metallic powders or to produce mechanically alloyed compacts.
The number of turns varied from 0 to 10 and torsion straining was applied at 3 rpm.
After HPT it was verified that there was no significant grain refinement, in all conditions the calculated mean crystallite size was 12 nm.
These Figures show an increase in the density of defects, in the form of micro-cracks, with the number of turns.
The increase of the number of defects could cause an increase in the number of preferential nucleation sites for hydride phases, especially micro-cracks that could facilitate the hydrogen diffusion in bulk hydride specimens.

And the average grain size D for these samples is 39.7, 37.1, 33.4, 31.9, and 31.2nm, respectively, decreases with the increasing of Cr ion.
And a number of double perovskite compounds have been known, where the Curie temperature can be as high as 635 K [3].
The average grain size D and the unit-cell parameters for the samples decrease with the increasing of x, as shown in Table I, for the smaller radius of Cr.
At low applied fields, the randomly alignment spins located at the grain boundaries can be easily tuned to align along the direction of the applied field resulting the low field MR.
And the average grain size D for these samples decreases with the increasing of Cr ion for the smaller radius of Cr (61.5pm) than Fe (64.5pm).

Microstructure of Ni-base weld was the cellular and columnar dendrite, and the grain was coarse.
Near the fusion line, the grain was small, the carbide was distributed on the grain boundary, and the shape of intergranular crack existed.
The grain was coarse and the grain boundary is wide.
The unit participated in the power peak load, and the time of start and stop was too much, and was far more than the specified number of times.
(2) The coarse grains of the weld metal and too long time staying in the sensitized temperature region result in the intergranular corrosion of weld metal.

The grains are of irregular shape and complex geometry, with a large number of grain boundaries.
At higher magnification, Fig. 6, one can observe a large number of small, fine spots within the grains (black arrows).
In the same figure, white arrows mark the spots at which separation of the grains and crack initiation started.
As one can see in Fig. 7, light microscopy makes it possible to analyse the grain size and shape, as well as void distribution.
Comparing Fig. 8c and 8d one can observe a larger number of deeper voids in old material fracture surface, which indicates the larger number of initial locations at which the voids formed and propagated.