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SEM examination showed that the grain size of sintered body is smaller than 300 nm.
A number of researchers have demonstrated superplasticity in several Si3N4 ceramics by applying the transient liquid phase [3-7], using ultrafine β-phase powder [8-13], or by adding secondary phases into Si3N4 to refine the microstructure [14].
Micro- structures of as-hot-pressed materials are very fine and uni- form, with average grain sizes about 300nm.
Alternatively, at constant stain-rate, the forming temperature can be decreased with smaller grain size.
The average grain size of sintered body is less than 300 nm

In the other word, Mg alloys have low strength and a small number of slip systems and are more difficult to work forming.
Recent studies showed that hydrostatic extrusion had a distinctive impact on the microstructural development of Mg alloys leading to finer-grained microstructures with average grain size of only a few micrometers, depending on the parameters used.
Before hydrostatic processes, the microstructures of AZ31, AZ61, AZ80 and ZM21 exhibit rather coarse grains with a grain size between 300µm and 500µm.
ZK30 and ZE10 alloys have smaller grains with a diameter of about 40–60µm.
But it can be assumed that besides the interaction of grain size and twinning the chemical composition has also an influence on the anisotropy because in spite of similar grain size of the microstructures of ZE10, AZ31 and ZK30 TYS and CYS are different.

When at the same temperature (1100 oC) , when strain rate increased by 0.01 s-1 up to 5 s-1, deformation grain gradually refining, DRX becoming more and more obvious, the volume fraction of DRX grain increasing gradually, complete DRX almost happened in the 5 s-1, which can be seen from fig. 6 (g~h), among which grain size are g (26.58 ηm) and h (20.61ηm).
As the temperature is reduced, grain size decreases gradually, as shown in figure 6 (h~a), grain size are h (20.61ηm), f (19.56 ηm) and a (16.98 ηm).
This is due to high temperature, grain is easy to grow up, but in low temperature it has no enough time to grow up.Along with the strain rate increasing or the deformation temperature reducing, DRX grain grew fine and distributed uniformly.
In higher temperature, with strain rate increasing, grain of DRX takes a great trend of refinement, moreover deformation temperature and strain rate take a great influence on DRX of SA516GR70 steel grain size.
Metallic recrystallization and grain growth [M].

It was observed the presence of nanograins (<100nm) for all samples, with average grain diameter under 300nm.
FTIR spectra were obtained within the range between 4000 and 450 cm−1, with resolution of 4cm-1, and the number of scans was 32.
The grain size of the biomaterials was measured through SEM images.
The image analysis method for grain size measuring allowed a statistical statement average of grains diameter.
RESULTS FOR AVERAGE GRAINS SIZE FOR THE DIFFERENT BIOMATERIALS (SD = STANDARD DEVIATION).

The optimal grain size is determined and optimal modes of grinding were identified to provide conformity of structural parameters for carriers.
It is stated that for structure with numerous contacts between grains, rheological properties of mixture are mostly determined by the thickness and properties of solvation shells on the grains.
However, there are still number of technological constraints inherent for the proposed approach.
According to proposed model the optimal grain size of mineral carrier is from 5 to 20 microns.
On the surface of grains, bitumen is under influence of the molecules of the surface layer of mineral materials [12…15].

N is the number of potential slip systems of the crystal: {111}<110> for fcc metals (N=12) and {110}{112}<111> (N=24) or {110}{112}{123}<111> (N=48) for bcc metals.
As the LAMEL model, the Grain Interaction Model (GIA) is a cluster model, but it treats a cluster of 8 grains instead of 2 grains [17]. 12 boundaries between sets of 2 grains exist within such cluster.
A B C D E F Grain α Grain β Region 1 Region 2 y1 y3 Fig. 3.
In this averaging procedure, part of a grain's volume is assigned to a particular grain boundary segment [10].
The model operates inside a given grain and interacts with the mesoscopic model for that grain.

Using the oxide of high melting-point and high stability to pin the grain boundaries is an effective method to improve the welding performance of the HSLA steel in this study.
Therefore, using the oxide of high melting-point and high stability to pin the grain boundaries is an effective method to improve the welding performance of the HSLA steel in this study.
As the content of manganese increases, the beginning transformation temperature of grain boundary ferrite decreases dramatically, promoting the formation of the acicula ferrite and restraining the formation of the pearlite. (2) The microalloy method combines with the thermo mechanical control process (TMCP). ① Use the composite microalloy (Nb, V, Ti) to produce grain refinement and precipitation strength [7].
In addition, calcium oxides as the second-phase particles prevent the growth of the austenite grains by pinning the austenite grain boundaries.
According to the pinning force formula of the particles [8], the pinning force to the original austenite grains becomes greater when the number of the particles increases and the size becomes smaller.

EBSD analysis was carried out to study the grain size and grain orientations.
The grains are detected by different colors and each color represent the crystallographic orientation of the grain.
The grain orientations or texture are studied with the help of pole figures.
The presence of larger grains results in the increase of overall texture intensity.
Due to the small number of grains present in the microstructure of both the specimens, the texture intensity values are significantly higher and it can be also concluded that these materials are not perfectly isotropic.

Ti in the form of fine TiN particles is able to avoid austenite grain growth, but it also can intervene in the austenite conditioning [[] M.
In a high number of TSDR (Thin Slab Direct Rolling) mill configurations, the thin slab goes directly to the finishing mill (CSP in Fig. 1).
As a consequence, the initial coarse as-cast austenite grain size must be refined and conditioned in only 5-7 rolling passes.
The analysis of the as-cast austenite shows the presence of an important fraction of grains coarser than 1 mm (an example of the grain size distribution is shown in Fig. 1).
In this context, the size and fraction of fine TiN particles, formed mainly during post-solidification conditions, can play an important role in the delay of austenite grain refinement.

The contour numbers indicated the power dissipation efficiency η and the shaded areas represented the instability region.
Specimen with Widmanstätten microstructure deformed at 920°C and 0.01 s-1 in Fig. 4a showed that the original lamellar α structure is almost changed to equiaxed α grains and many fine recrystallized a grains could be seen due to the rapid recrystallization velocity of the a phase than that of the b phase [13].
The microstructure displayed homogeneously equiaxed β grain about 80µm with acicular α plate martensite.
Within the bands of flow localization fine recrystallized a grains are found.
Hot deformation led to the formation of a mixed grain microstructure consisting of small equiaxed recrystallized b grains in a localized region and large pancaked prior b grains.