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Grain size decreased with decreasing in cooling rates.
Three major regions were observed; the dynamically recrystallized (DRX-ed) α-Mg fine-grains region, the hot- worked α-Mg coarse-grains region, and the kink-deformed LPSO phase region.
Although average grain size of the DRX-ed grains in the extruded alloys was ~ 4 µm regard- less of different SDAS, area fraction of the DRX-ed region increased with decreasing SDAS.
To describe the change in a dispersion of LPSO quantitatively, dispersion level, DL (mm-1), was defined for discussion by the following expression in this study, DL = Σ v / ΣLv, (2) where Lv (µm) is length of a segment L that is vertical line drawn against extruding direction in Fig. 3, and v is number of LPSO phase that intersects with a segment L.
The DRX-ed α-Mg fine-grains largely contributed to the improve- ment of the ductility of the alloys.

A number of grain refining additives have been discussed such as Ca, Sr [14, 15, 16] or even Mn [17].
Small pinning particles of stable intermetallic compounds could be used as grain stabilizers preventing further grain growth to a certain extent.
However, the application of forged parts based on magnesium is restricted to a small number only [4, 25].
Fig. 11 shows two flow-curves at 350°C of the materials in the DC-cast condition, one is coarse-grained with an average grain size of 400 µm, the other is fine-grained with 80 µm on the average.
Fig. 12: Conventional coarse grained sample (left) and fine grained sample (right) after deformation.

Microstructural examination showed the grain sizes of both alloys were reduced to the range of ~0.3-0.5 µm through ECAP.
The Al-7034 billets were pressed at 200°C and rotated by 90° in the same direction between consecutive passes in the processing route termed BC and the Al-2024 billets were pressed at room temperature using route Bc-C where they were rotated by 90° after odd-numbered passes and by 180° after even-numbered passes.
The as-received Al-7034 alloy contained a fairly equiaxed array of grains with an average grain size of ~2.1 µm and there was a low density of dislocations [7].
These peaks move slightly to higher temperature with an increase in the number of ECAP passes, and they occur at 376, 380 and 394°C for 2, 6 and 8 passes of ECAP, respectively.
This effectively reduces the number of obstacles available to impede the movement of dislocations.

It could absorb crack propagation along grain boundary.
And it played fine grain role on this ceramic.
Increased crack propagation path, grain refinement and more grain boundary of AlON were all caused by SiC pined on AlON grain boundary.
The sample grain was smaller with more SiC added.
Acknowledgements This work was supported by the National Nature Science Foundation of China (grant number 50672060) and the Shenyang Science Fund (grant number 1081237-1-00).

Inversely, at lower sintering temperature, such as 900ºC, the sample exhibited smaller grain size, which contributed to a higher amount of amorphous grain boundary phase compared to that in the samples with larger grain size.
The higher number of contact points between the particles activates the transport of matter, leading to the higher number of necks between the particles, enhancing the diffusion and evaporation-condensation of the matter on surfaces with consequent bulk densification.
The understanding of the development of the morphological features i.e. grain, grain boundaries and pores is important because a high amount of porosity and larger number of grain boundaries would be effective pinning centres to domain wall movements, hence increasing the demagnetizing effect in the sample which results in decreases of magnetization.
Increase in the density and grain size and the decrease in porosity with sintering temperature would influenced the permeability where large grains diminish the number of grain boundaries, therefore results in reduced the hindrance of the domain wall motion.
Besides that, the fraction of grains that are occupied with domain walls increases in the larger grain thus increases the eddy current and hysteresis losses.

The original grains are generally visible but the density of LAGB and HAGBs inside the grains is much lower: the strong influence of temperature on reducing grain fragmentation in Al-Mg alloys is clearly seen.
In the 3D grain texture simulations involving 14-sided grains, this grain coalescence by lattice rotations to 3 texture components leads to long, interpenetrating "orientation chains".
Fig. 4 illustrates a 2-D section of the evolution of grain structure and texture components during a grain interaction texture simulation.
It is important to note that at the end of each cycle (n x 3 x 0.2 where n denotes the number of cycles), the RCSQ is close to zero, which means that on each one of the 12 slip systems, the slip quantity produced by one increment ends up being annihilated during a future increment.
Since the texture components are fewer in number as compared to the grain neighbors on average, this leads to significant grain coalescence and eventually the formation of "orientation chains".

Imaginary part of the pseudo-dielectric function of a µc-Si:H film deposited on a-Si:H by the layer-by-layer method and measured at increasing number of cycles.
On the contrary, if the hydrogen flux is too high, a fast crystallization will be obtained but this will result in reduced grain size because of competitive growth of the high number of nucleation sites.
The numbers in brackets indicate the values of the RF power and the partial pressure of silane.
Besides crystallinity, the quality of the grains is an important parameter for electronic applications.
PSil stands for large grains polysilicon and PSif for fine grain polysilicon.

Good penetration of copper along the grain boundaries of the 60% porosity sintered ceramics was analysed in the whole volume of composite.
Linear dependence of the amount of loss material on the number of electrical discharge analytical cycles for Cu/ZrB2 composite was determined.
The dependence of overall loss of weight with the number of electrical discharge analytical cycles was determined.
Any contact angle decreases were due to volume shrinking connected to the geometry of voids and grain boundary energetics.
However, the presence of open porosity in the sintered ceramics gave the opportunity to show good penetration of molten copper along the grain boundaries [1].

The amorphous precursor is crystallized to the epitaxial α-Fe2O3 grains in three steps with annealing temperature; i) the growth of the well aligned α-Fe2O3 interfacial crystallites to approximately 200-Å-thick, together with the transformation of the Fe3O4 crystallites to the α-Fe2O3 crystallites (< 400℃), ii) the growth of the less aligned α-Fe2O3 grains on top of the well aligned grains (> 400℃), and iii) the nucleation of the different less aligned α-Fe2O3 grains directly on the α-Al2O3 substrate (> 600℃).
The importance of iron oxide films led to an increasing number of surface science and film growth studies [5-7].
The inset of Fig. 3(a) shows the rocking curve of the crystallized α-Fe2O3(0006) grains at 600℃.
From these results, we suggest that the less aligned α-Fe2O3 grains, having the nucleation temperature of ~400 ℃, are homogeneously nucleated on top of the well aligned grains, as a preferred nucleation site.
The second step is the growth of the homogeneously less aligned (3.08 o FWHM) α-Fe2O3 grains, having the nucleation temperature of ~400℃, on top of the well aligned grains keeping grow to the CDS of 200 Å in the film normal direction.

Effect of Increase of Dihedral Angle on Thermal Grain Boundary Grooving W.
Also, backscattering electron Kikuchi patterns for each grain adjacent to the groove in Fig. 4 changed across the groove root confirming the existence of a grain boundary below the groove root.
The number of spatial mesh points used in computation is 401 and the error tolerances in time integration are set to 10 -9.
During this period the grain boundary grows longer and the total surface area decreases.
The newly formed grain boundary is almost straight in the simulation.