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Another matter to preserve fine grains while sintering is addition of second phase to pin grain boundaries.
The average grain size were measured based on an appropriate number of SEM images of each sample, allowing the measurement of more than 200 individual grains, using an image analyzer (Image Pro Plus, Version 5.1, Media Cybernetics).
The zirconia inclusions hinder the movement of grain boundary, reducing the densification rate and grain growth [28-30].
Conclusion Fine zirconia grains in the sintering sample induce a pinning effect on grain boundary migration of alumina.
Thus, the degree of the grain growth during the sintering is effectively reduced.

Arrows indicate quenching point for the different homogenisation treatments where ν is the growth rate and NTOT =NPSN + NGB. is the total number of nucleation sites.
The total number of PSN sites, NPSN, is determined by an integration of the particle size distribution f(η)=LN0.exp(-Lη), where N0 and L are characteristic distribution parameters.
The density of PSN nuclei becomes:         − − = ' zD GB oPSN PSN PPL4 expNCN γ (5) where CPSN is a constant which determines the number of recrystallised grains nucleated at each particle that is larger than η*. η* is a critical particle size for a successful nucleation of a grain, which can be derived from the Gibbs-Thompson equation, i.e. η*=4γGB/(PD- ' zP ).
Together with an explicit expression for the density of nucleation sites from old grain boundaries (NGB) [1], this gives the total number of nucleation sites.
In modelling terms an increased Zener drag 'zP results in a higher critical particle size, η * , which mean that the critical particle size to cause nucleation by PSN increases and the number of nucleated grains by PSN decreases, resulting in a much coarser recrystallized grain size in this case.

The name TMP was coined about 1960 to describe controlled rolling of austenite in which pancaked grains with refined substructure were chilled to produce highly refined grains in ferrite or laths in martensite [1, 2].
When the grains are as thin as 2dS, they pinch off into short segments in a mechanism called grain-defining gDRV (grains can never become thinner than ~2dS) [9,23,25].
Hot rolling is usually conducted at declining T in the range 500 to 250˚C in a multi-stage schedule (Ti, i, ei ti, i pass number up to ~20) on cold rolls, so the grains are usually pancaked, especially if the alloy contains dispersoid or precipitates at GB; often strip is given SRX for cold rolling [9,16-20].
In torsion simulations, the flow stress and substructure evolution were examined in each pass Ti, ei and interval ti with changes in number of passes and in [18-20].
In semi-solid forming, an alloy pretreated so that the grains have solute less than the liquidus and with a liquid constituent of low melting phases flows into the dye at pressures too low to cause much strain hardening in the grains [43].

The mechanism of refining grain in the compound process is probed.
To save the cost of preparation of semi-solid slurry, the fining of grain size and improvement of grain morphology by controlling pouring temperature or low pouring temperature were realized[1].
The mentioned results mean that there are the obvious effects on grain size of primary α-A1 by the compound process, especially on the grain size at the edge area.
Finally, the nuclei formed in the melt are copious in numbers so that the resulting grains could be finer and smaller in size.
The resulting grains are finer than that obtained by LSPSEMS.

The number fraction of the KAM more than 1°, f[θ>1] was 33.0%.
The fraction is selected as another index of the stored energy because the number fraction of the KAM not more than 1° was 96.6% for the 0P sample.
The sheet has been CCBent and annealed to consist of the coarse-grained surface and the fine-grained center layers.
Grain sizes were measured by the liner intercept method as about 64µm and about 8µm for the coarse- and fine- grained layers, respectively.
Fig. 4 Fractions of primary orientation components in the coarse-grained surface and center layers immediately before tensile testing, and after deformation to failure at 713K and various strain rates. 0 10 20 30 40 Initial strain rate, ε /s -1・ Number fraction(%) Before testing 1.4×10 -1 5.6×10 -3 5.6×10 -4 0 10 20 30 40 Initial strain rate, ε /s -1・ Number fraction(%) Before testing 1.4×10 -1 5.6×10 -3 5.6×10 -4 (a) Surface layer (b) Center layer <111>//RD <001>//RD <011>//RD Figure 4 represents fractions of <001>//RD, <111>//RD and <011>//RD in the surface and center layer.

Voronoi diagram is partitioning method that space is divided into a number of regions.
It is well known that diamond abrasive grains have wear flats in grinding processes.
The number of extracted cutting edges was 72,304.
Fig.5 shows the number of cutting edges with any extracted area every one pixel.
This is about 42% for the area of the average grain diameter 100µm.

An external force of vibration was not exerted to the mould but a chilling generator introduced into the alloy melt, and vibrating the chilling generator can produce a large number of nuclei for forming equiaxed crystal grain.
Considering the length l of the primary phase grains is very small, it approximates that .
The formula (9) shows the main factors of the grain free, which include the vibration frequency, amplitude, chilled temperature and the surface state of generator (corresponding to the wetting angle).In addition, the grain aspect ratio and the neck coefficient determine the size of the coefficient , which affect the ease of grain free.
The grain which has necking is more likely to be free, but necking is not the only prerequisite for grain free.
Figure 2 (b) shows that no detachment of grains occurs.

At sufficiently high temperatures PLD deposited TaC films can be grown epitaxially on 4H-SiC (0001) substrates; at lower temperatures the films recrystallize and ball up forming a large number of pinholes.
One interesting possibility is that TaC could grow epitaxially on the SiC making it much less likely that grains will ball up on the surface due to poor adhesion when the substrate is heated to 1600°C, or that openings in the patterned TaC will change their shape when grain growth occurs.
not perfect, however, as there are some extra, but significantly weaker spots that belong to misoriented TaC grains.
The micrographs show systematic changes in the morphology caused by the recrystallization and grain growth of TaC.
High temperature annealed epitaxial TaC films exhibited a smooth surface and interface morphology and no pin hole formation, while oriented films deposited at lower temperatures recrystallized when they were annealed forming a large number of pin holes and a very rough surface composed of faceted grains.

Therefore, how to improve the performance of grinding wheel by ordered grain arrangement have become a hot issue in the grinding field [1-3].
The abrasive raised height of the end wheel presents gaussian distribution, therefore, the mathematical track equation of grain ni on the wheel surface is established as: (2) where , , , , M is grains density, is the grains average dimension, is grains largest size, is grain mean value, is standard deviation.
The number of grains is increased with decreasing of phyllotactic coefficient k, meanwhile the grains number which scratch across surface is also increased under the same grinding conditions, thereby the surface roughness value of the workpiece is reduced.
[3] Pinto F W, Vargas G E, Wegener K: Simulation for optimizing grain pattern on engineered grinding tools.
[4] Aurich J C, Herzenstiel P, Sudermann H, et al: High-performance dry grinding using a grinding wheel with a defined grain pattern.

For the structure of the sample is characterized by a large number of particles of oval shape, with characteristics that match starch grains.
Individual grains slightly deformed.
Perhaps this is caused by different number penetration power of drinking water.
The structure is friable enough, as there are a large number of air pockets.
Only some few grains of starch grains of starch are in direct contact with each other [5, 6].