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With increasing of TiB2 particles, the number of TiB2 particles smaller than 200 nm will increase in the grain, resulting in the increase of the capability of heterogeneous nucleus (in the grain), and nucleation is the main function of TiB2 particles at contents below 4.5%.
The globular grain on the bottom whose mean grain size is about 250mm and shape factor is 0.94 in Fig.8.
The globular grain also begins to melt into rosette grains on the bottom.
As the holding time increasing, dendrite grains are necked and remelted at first, then rosette grains melt and shrink into globular grains, finally the globular grains begin to grow, but the number of grains decreased and their mean grain size increase since some contiguous grains merge into bigger grains by coalescence and small grains disappear by diffusion through the solid phase.
As the holding time increasing, dendrite grains are necked and remelted at first, then rosette grains melt and shrink into globular grains, finally the globular grains begin to grow, but the number of grains decreased and their mean grain size increase since some contiguous grains merge into bigger grains by coalescence and small grains disappear by diffusion through the solid phase.

Since isostatic pressing can densify the perovskite film, it may also reduce the number of grain boundary defects in the perovskite film, thus enhancing its thermal stability.
The CIP treatment effectively densified the PMMA-MAPbI3 film, reducing the number of GBs within the film.
The pristine control film consisted of densely packed small perovskite grains.
Despite the presence of PbI2 nanorods, the CIP-treated 5 h film still retained many of its perovskite grains.
By compressing the film under high pressure, CIP densified the film and reduced the number of GBs acting as defect sites.

The TiAl alloy with fine grain via reactive sintering was obtained.
The microstructure of TiAl intermetallic alloy shows equiaxed grain that the average grain size is 5~10µm (Fig.8).
The grain size of TiAl alloy has been grown slightly but the shape of the grain is not changed.
The grain size is average 8µm.
Acknowledgements This work was supported by the Postdoctoral Foundation of Heilongjiang Province under grant number AUGA41000551.

In mathematics, a Voronoi diagram is a way of dividing space into a number of regions without overlaps and gaps.
As mentioned above, polycrystalline microstructures in metallic alloys are represented using Voronoi tessellations in a significant number of researches due to their similar properties.
As is shown in the figure, the deviation of overall stress with 1000 elements and 27000 elements is less than 3.5%, while the average number of elements per grain of the latter is 27 times as the former.
The aggregates with 1000 C3D8 elements and 10000 C3D4 elements, or aggregates with 8000 C3D8 elements and 66000 C3D4 elements have nearly the same number of average integration points per grain, but the deviations of overall stress when strain is 0.1 between them are 5.1% and 5.3%, respectively.
(c)and(d) Regular mesh and free mesh with nearly the same number of integration points.

In a number of materials subjected to large strain, a superposition of surface roughness of varying wavelengths is observed.
Figure.3 shows the statistic of 500 coarse grain orientations.
Crystal orientation map (COM) of the cross section: (a) Coarse grain and forming orange peel (b) Coarse grain but no orange peel Fig. 3.
Schematic diagram showing the Schmid factor calculation of the two kind coarse-grains:(a)Coarse-grain with the {100}<001> orientation.
Acknowledgements This work was supported by the National Natural Science Foundation of China under grant number 50171040.

To consider the effect of grain size refinement, it is instructive to examine the contribution of atomic species residing in the grain boundary relative to that of the total atoms in a nano-grain.
This is shown in Fig. 1, which depicts the percentage of atoms in the grain boundaries as a function of grain size for two assumed thickness values for the grain boundary, 0.5 and 1 nm [5].
As the grain size is reduced, the number of atoms in the bulk (and their contribution) diminishes and becomes zero with the overlapping of the space charge layers.
Grain size dependence of percentage of atoms in grain boundaries assuming boundary widths of 0.5 and 1 nm [5].
Fig. 2.Reduction of the bulk relative to space charge layer and grain boundary as grain size decreases.

Experimental Investigation of Brittle to Ductile Transition of Single Crystal Silicon by Single Grain Grinding F.W.
Grinding is a very complex manufacturing process which is involved with a great number of variables, such as wheel type, wheel condition, operating parameters, coolant condition and machine characteristics.
conducted single grain grinding experiments on a modified wafer grinding machine [6].
Fig. 3 3D image of single grain grinding groove shown in Fig. 2(b) Material response based on subsurface damage.
Therefore, below a critical depth of cut, cracks will fail to form around the cutting grain.

The local strain in analysed place of probes on their sections was obtained by stereological measurement of degree of grain boundaries orientation, which is proportional to grain boundaries deformation degree.
From the relative number (number to unit of length) of parallel test lines intersections with grain boundaries (PL)P and perpendicular lines ones (PL)O was total relative surface area (SV)TOT of grains estimated according to Eq. 1.
Planar oriented part of relative surface area (SV)OR of grains was estimated according to Eq. 2.
From this values degree of orientation of grain boundaries O was estimated as ratio of (SV)OR and (SV)TOT
The higher number of holes was drilled to the same wear by coated drill.

The sample was milled to 60 μm on 2000# sandpaper and then punched into a number of wafers with a diameter of 3mm.
Many small recrystallized grains appear around the grain boundaries of the large grains, with an average grain size of 20μm.
As the number of passes increases, the intensity of diffraction increases continuously.
There are many small recrystallized grains with rigid nucleation around the grain boundaries of large grains, and the grain boundaries between them are small angle grain boundaries.
There were many small recrystallized grains at the grain boundaries of large grains, and the grain boundaries between them were small angle grain boundaries.

The influence of ram speed on grain structure evolution was analyzed.
A number of models, such as the Laasraoui-Jonas model (LJ model) [7], the KM model [8] and the two-parameter model [9], have been used to describe the evolution of dislocation density in grains.
Different shades represent different orientations of grains.
The black lines represent grain boundaries.
Most of grain misorientation angles are larger than 150.