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The average grain size was less than 500nm if the sintering temperature was below 1700℃.
The aspect ratio of some grains reached 1.5.
A number of researchers have demonstrated superplasticity in several silicon nitride ceramics by applying the transient liquid phase, using ultrafineβ-phase powders, or by adding secondary phases into Si3N4 to refine the microstructure.
The grain size was observed by SEM experiment.
Although the average grain size was 150nm at 1500℃, the density was only 90.3%.

Journal Title and Volume Number (to be inserted by the publisher) 2 Fig. 2.
AMSDAMSDAMSDAMSD Journal Title and Volume Number (to be inserted by the publisher) 4 (a) (b) Fig. 5.
Schematic drawings of grains (hexagons) (a) before and (b) after grain growth under stress.
The grain growth rates are determined by the migration velocity of grain boundaries.
The evolution of the {111}<110> and {111}<112> orientations can be explained by Journal Title and Volume Number (to be inserted by the publisher) 6 the SERM model, in which grains whose MYMDs are parallel to AMSD in the trenches grow in preference to others.

The average grain size of 7075 aluminum alloy was refined to 12.81μm from 19.62μm at 300℃ for durations of 40min.
Because of grain refinement after annealing, the hardness of base metal increased significantly.
In B point, atomic number ratio between aluminum and magnesium was about 3:2.
In this case, diffusion layer width and grain size were relatively moderate and the joint strength was maximized.
But grain size grew up seriously, large numbers of intermetallic compounds formed.

For recrystallized grains orientations were assigned randomly from a list of grain orientations measured in an EBSD experiment.
Journal Title and Volume Number (to be inserted by the publisher) 3 Figure 2.
On the other hand, as the boundaries between recrystallized grains are mainly high misorientation (high angle grain boundary, HAGB) they tend to be associated with a high GB energy.
Journal Title and Volume Number (to be inserted by the publisher) 5 (a) (b) Figure 6.
Note however that a number of boundaries remain pinned along the original boundary of the band, as is often observed experimentally.

F1=Fm+Fg+Fa+Fτ F2=Fd F1=F2 (3) The grain size depends on the number of nucleation.
The more nuclear number, the smaller sizes of grains.
The distribution of bubbles is affected by the number of nucleation and crystal growth[16].
Based on the relation, to build three kinds of models as follow: Model A: The large number of nucleation would decrease the average grain size, so that the distribution of nucleation around the bubbles is dense (Fig. 6(a)).
Model B: when the number of nucleation is low, the average grain size is big.

The double Scohottky barriers at the grain boundaries between every two ZnO grains have been validated as the origin of the nonlinear characteristics.
Generally, Newton iterative method is used to solve above equations, which will become quite time-consuming when the number of equations is large.
In subarea III, two ZnO grains are touched directly.
The values of above impedances depend on the actual sizes of ZnO grains and grain boundaries.
Pores and twin grains.

However, compared with a pure Cu film, salient grain growth of present dilute alloys does not takes place even at temperatures above 300 ºC , where the grain size is nearly the same as that of as-deposited films.
A large stress relaxation started to occur above 250ºC, associating with a large number of hillock formation.
Therefore, a large number of solute atoms most likely still remain in the Cu matrix, resulting in only a small decrease of resistivity at elevated temperatures.
It is clearly seen that on annealing at 400℃, the pure Cu film shows a large grain growth associating with a large number of void formation (dark spots in the photo), Fig. 4.
However, compared with a pure Cu film, grain growth of present dilute alloys does not significantly take place, showing nearly the same grain size as that of as-deposited films even above 300 ºC.

Presence of coincident site lattices (CSL) on grains boundaries was investigated by repere diffraction method [1].
Intensity of grains orientations grows with ТFR Fig.5.
The following aspects: increase of grains number with cubic and octahedron orientations at controlled rolling; macrosymmetry (axis 4) of areas with higher pole density; as well as azimuthal distribution of zone pole density - testify dynamic recrystallization (DR) of steels in this area.
Significant number of special boundaries has been revealed here by repere diffraction method, which are characterized by presence of coincidence site lattice (CSL), for instance, tetragonal CSL (Fig. 9).
Grain maximums {111} accompanying them in this temperature range contribute to properties of low-alloy steel as well [4-5].

The ECAP of the alloy results in the formation of ultrafine grained structure with a grain size of 0.8-3.5 µm independent of pressing routes and regimes.
However, at lower deformation temperatures, the plasticity and deformability of the alloy noticeably decrease because of a limited number of the effective systems of deformation.
Results and discussion The microstructure of the pressed and annealed Mg-Al-Zn alloy bar (before ECAP) is characterized by a substantial variation of grain size, from rather coarse (exceeding 15 µm) to fine grains (2.5 - 4 µm).
The ECA pressing by the regimes given in Table 1 resulted in the formation of ultrafine grained (UFG) structure with a grain size ranging between 0.8 and 3.5 µm.
The grain size in the magnesium alloy does not virtually depend on the ECAP regime and route.

Strain of Grains.
The total number of grains used for the measurement was about 240.
The numbers of measured grains is about 240.
Namely, the grain shape mainly affects the rotation of grains
(3) The standard deviation of the strain among grains is small for those grains with large grain size.