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It show that the number of crystal planes that satisfied the Bragg law is reduced, and the grain size is smaller, so it can be indicated that the degree of crystallization is worse.
The Si2ON2 grains well combined with SiC grains to form a three dimensional net and protect the SiC grains not oxidation in the air.
Small Si3N4 grains also can be seen adherent on Si2ON2 grains.
It can be infered that most Si3N4 grains are generated from the decomposed Si2ON2 grains.
It can be seen that columnar Si3N4 grains are adherent on SiC grains, and almost no Si2ON2 grains can be seen in the image.

And the Al2O3 nanoparticles and Ni grains diameters in thin films are about 40nm and 80nm, respectively.
It is explained that Ni-Al2O3 films obtained by pulse current electrodepositing showed compacter surface and less grain size, while those obtained by direct current electrodepositing were rougher in surface and bigger in grain size.
According to the theories in electrodepositing, the stronger the cathode polarization is, the faster the rate of crystal nucleation, and the more the number of nucleuses.
Therefore, the film can be obtained with a compact surface and fine grains.
And the Al2O3 nanoparticles and Ni grains diameters were about 40nm and 80nm, respectively.

Substantially larger grains could be recognized for sintered samples with the addition of BaF2 (Fig. 3(B)) and CaF2 (D), indicative of the promotion of grain growth in the presence of these additives.
Liquid phase has been cited as a major causes of this kind of abnormal grain growth [11].
Activation energy for oxide ion conduction tended to increase as the number of cation vacancies decreased for the LSO samples with oxygen stoichiometry (No. < 1 > → < 4 > → < 5 >).
Ba3Al2F12 additive had similar effects on the densification and grain growth but a stepwise sintering (1400ºC/5 h → 1450ºC/5 h) brought about the inhibition of abnormal grain growth at 1450ºC.
On the contrary, the BaF2 addition positively assisted both the densification and grain growth.

There are also some small grains distributed in the grain boundary, indicating that the dynamic recrystallization occurred during hot extrusion.
This type of recrystallization grains became more Fig. 1.
Besides many recrystallization grains, a lot of twins on the grains are observed in both as-rolled sheets as shown in Figs. 3c and 3d.
The improved plasticity is considered due to the finer grain size resulted from the increasing pass numbers.
It is clearly from Eq. 1 that a fine-grained rolling sheet is stronger than one with coarse grain size because it has a greater total grain boundary area to impede the motion of dislocation.

The grain refinement theory.
For 125K ≤∆T≤195K, dendrites are regenerated, but the grain size is reduced (Figs.1c).
According to Karma’s model for dendrite fragmentation, the grain refinement of undercooled Ni-11%Si alloy was in good agreement with the experimental data, and the grain size was reduced with the increasing ΔT.
Karma, Model of grain refinement in solidification of undercooled melts, J.
Herlach, Physical mechanism of grain refinement in undercooled melt, Phys.

In the microstructure of normal direction (Fig.2-a) , much dendrite structure of initial primary phase are found, which are mainly coarse grain with rough and irregular boundary.
But due to the shearing action during the rolling process, little part of the coarse grain of primary phase are bended and broke into globular granules with smaller size.
Beside of high developed dendrite structure, in the microstructure of cross section of metallographic section without outside field (Fig.2-c) , a number of local-concentrated and plate shaped dendrite grain are formed, because of shearing action and limited floating space in the cross section direction.
Because of scour from the liquid phase and collision between the nucleus during the growing process, the new crystal nucleus are passivated and formed into spherical or rose-shaped dendrite grain finally, besides, the average grain size has been reduced greatly form 60-80 μm to 12-18 μm, showing that outside energy-field can make significant contribution to homogenization of the concentration field in rolling process.
To sum up, fine and uniform equiaxed grain will be obtained by cast-rolling process with composite outside energy-field.

The decomposition of tempered martensite lath was retarded after adding a number of alloying elements such as Cr, Co, W, Mo, V, according to observations by transmission electron microscopy.
It also shows that the fine dispersion secondary carbide precipitates along the martensite grain surface and grain boundary.
The decomposition of tempered martensite lath was retarded after adding a number of alloying elements such as Cr, Co, W, Mo and V, and it would result in better tempering resistance.
A number of alloying elements being added to steel makes the decomposition of tempered martensite lath retarded, which will cause the better tempering resistance.
The decomposition of tempered martensite lath was retarded after adding a number of alloying elements.

The XRD shows that a sample is primarily in both tetragonal and rhombohedral phases coexist and the amount of rhombohedral phase decreases that is due to the donor (Nb) dopant reduces the number of oxygen vacancies and leads to a lower amount of rhombohedral phase.
Above the limit, the excessive Cr ions segregate at grain boundary and inhibit the grain growth.
The grain size then increases at higher concentration of the doping.
Both of Nb and Cr impede the grain growth, which explains the decrease of the grains from 0-0.6 mol% Cr doping.
After that the grain size increases, which can be attributed to the more solubility of Nb (donor dopant) and Cr (acceptor dopant) in the system, resulting in the balancing of the excessive oxygen vacancies which leads to enhanced grain growth.

The scanning electron microscope (SEM) was used to observe the grain size.
The grain size was determined by averaging over the total number of grains in the SEM micrograph and found to be increased from 0.18 to 0.35 µm as the sintering temperature increased from 1200 to 1280 °C.
This is because larger-grained sample has lower concentration of grain boundaries [9].
Domain walls form harder when the grains are getting smaller.
For the PZT films, grain sizes increased with increasing Zr content.

The slit was 0.1 mm and very small grains are imaged.
Bigger grains are seen as longer streaks with the streaklength corresponding to the grain diameter in scanning direction (transverse direction).
They consist of a large number (e.g. >1000) of sharp and narrow peaks (e.g.
For the discussion of the experimental data it is necessary to know more about the relationship between the number of input orientations and the number of agreements with the calculated values.
Figure 18 Relationship between random number N and correlation with the calculated values.