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A very thin layer of fine equiaxed grain exists at both top and bottom subsurface layer, the thickness of the fine equiaxed grain layer at bottom subsurface is much bigger than that of top subsurface.
Coarse columnar and equiaxed grains layer with a certain growth direction form inside the fine equiaxed grain layer.
The coarse columnar and equiaxed grains layer in upper part is much thinner than that of bottom part, and the thickness of coarse columnar and equiaxed grains layer is about 20mm and 10mm at lower part and upper part of the ingot, respectively.
Feathery grains nucleate in the periphery of the coarse columnar and equiaxed grains layer, grow along the thermal transition direction with a characteristic fan shape and meet in the center of sump.
While, the ingot surface is coarse and large numbers of segregation knots occupy the whole ingot surface as the casting speed is 180 mm/min.

This material exhibits an excellent oxidation resistance at low and intermediate temperature, high melting point (2303 K) and thermodynamic stability with a number of important ceramics materials.
Fig. 3: SEM of the pressed MoSi2 powder with a pre heating, to reveal the grain shape.
A poligonal powder with large grains size can be seen.
Neck size ratio and shrinkage are small and the grain size is no large than the initial particle size.
No grain growth was observed after the laser sintering process, indicating the initial sintering stage predominance.

This paper analyzes the TTT and CCT curves of U75V as a research basis, detailed anatomical U75V chemical properties and grain structure, through thermal simulation machine, heating 820 ℃, respectively, and 920 ℃, respectively, the sample detection U75V 2 ℃ / s, 4 ℃ / s, 6 ℃ / s, 10 ℃ / s, 15 ℃ / s, 20 ℃ / s speeds cooled Rockwell hardness, and observing samples taken U75V phase diagram.
Effect of U75V rail pearlite interlamellar spacing under different cooling rates (a) 2 ℃ / s cooling (b) 10 ℃ / s cooling (c)20 ℃ / s cooling Fig. 5 When the heating temperature is 820℃, with 2℃/s, 10℃/s, 20 ℃/s cooling pearlite interlamellar spacing (a) 2℃/s cooling (b) 10 ℃/s cooling (c)20℃/s cooling Fig. 6 When the heating temperature is 920℃, with 2℃/s, 10℃/s, 20℃/s cooling pearlite interlamellar spacing It can be seen from Figure 5 and Figure 6.The mesh of precipitates along the grain boundaries is ferrite, the grain boundary precipitation is pearlite, white mesh is ferrite.
The white stripes inside the grains are ferrite, dark stripes are cementite.
Fig. 5 The pearlite interlamellar spacing curves at different cooling rate Number Heating temperature /℃ Cooling rate /℃/s Lamellar spacing /µm Hardness /HRC T1 820 2 0.182 29.46 T2 820 4 0.168 29.16 T3 820 6 0.125 35.06 T4 820 10 0.11538 36.58 T5 820 15 0.109 41.9 T6 820 20 0.1188 37.28 Table 4 The pearlite interlamellar spacing and hardness at different cooling rate Number Heating temperature /℃ Cooling rate /℃/s Lamellar spacing /µm Hardness /HRC T1 920 2 0.1744 30.96 T2 920 4 0.16352 29.10 T3 920 6 0.1084 37.98 T4 920 10 0.10706 39.90 T5 920 15 0.1043 44.74 T6 920 20 0.1225 42.82 Table 5 The pearlite interlamellar spacing and hardness at different cooling rate The table 4 and table 5 show that as the temperature decreases, the actual crystallization temperature dropping，increasing of the undercooling, reducing the diffusion ability of carbon in austenite, diffusion distance becoming short, pearlite lamellar spacing decreasing.

Techniques like ECAP are particularly effective in refining grain structures in magnesium alloys.
Secondary phases are seen as darker areas, probably arranged along grain boundaries and inside the grains.
Because of these, grains become elongated with respect to the rolling direction, can be seen in (b), often accompanied by grain refinement.
Precisely, the Mg alloys after homogenization show more equiaxed microstructures which reduce the number of localized active corrosion sites.
The microstructural examination showed that homogenization resulted in a uniform microstructure with equiaxed grains, dissolves micro-segregated phases, while hot rolling led to significant grain refinement, phase transformations and elongation of grains in the rolling direction. 2.

., reducing the number of masks, in order to increase throughput and yield.
This number has been reduced to 5 or even 4 in the most advanced factories (see below).
As stated above, in parallel to the substrate size increase, the AMLCD manufacturers have drastically reduced the number of masks for the TFT plate fabrication.
Top view SEM pictures of the grains are also shown for various particular energy values.
In order to overcome this problem, the pixel designs tend to be more complex and the number of transistors increasing to 3, 4 or even more [32, 35].

These findings proved that the addition of SiC particles able to retard the grain growth and gave rise to a finer β-Sn phase.
Reinforcement concentration between grains will tend to prevent and limit grain boundary sliding and retard the grain growth.
This process also contributed to delaying the growth of the grains, leading to finer microstructures [11].
Apart from that, the presence of reinforcement contributes to decreasing of solder matrix grain size.
Conclusion This study has proven with the addition of SiC particle in SnCu lead-free solder are able to retard the grain growth and gave rise to the number of finer β-Sn phase.

The relationship between angle versus the sand Reynolds number are plotted in Fig. 5.
The sand Reynolds number is defined as Re*=u*d/ν (where u* is friction velocity).
It shows that, the angle α grows with the increase of sand Reynolds number, the angle β, however, has a contrary trend.
The higher the sand Reynolds number is, the more obvious the trend will be.
The angle α increases with the growth of sand Reynolds number; but the angle β has a contrary trend which decreases with the sand Reynolds number

The microstructure of as-cast strips exhibited columnar grains normal to the strip surface.
According to empirical results for the viscosity of the liquid metals, the viscosity usually decreases with increasing the number and amount of alloying elements.
Because the increase of Cu-content in Ti-Ni-Cu alloy resulted in the reduced strip thickness, the strip of higher Cu-content achieved the large degree of undercooling and their long grains became refined and the dendrite structure.
Therefore, it is considered that the excellent shape memory characteristic such as the small temperature hysteresis of as-cast Ti50Ni15Cu35 strips is ascribed to the controlled microstructures (small grains and texture) that can be achieved by the rapid solidification process of the melt overflow.
This small hysteresis is attributed to small grains and texture structure introduced by the rapid solidification process of arc melt overflow.

As the stage number increases, the roughness gradually increases.
This is due to the coarsening of the grain.
The grain size of the cup heated at 800 o C is comparatively large.
It was found that grain refining treatment is effective for improving surface roughness.
Ironing and grain refining are effective for improving surface roughness.

The characteristic peak shows that a large number of TiO2 exist as anatase, small of it exist as rutile.
If the grain size is not far the wavelength, the satter effect will become stronger.
The mean grain size of SiO2 particle sample in TiO2/SiO2 of different molar ratio is shown in table 1.
This shows that the grain size of the SiO2 supported TiO2 is smaller than that of pure TiO2, which declares that the compound TiO2 can restrain forming crystalline.
The larger number of compound TiO2, the higher restrain power among particles, so the phenomenon of the restrain on grain growth become more obvious[9].