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It is determined that stirring temperature of 608ºC and stirring speed of 300 RPM leads to the uniform grains distribution and therefore arrives to better hardness for the produced billets.
A number of mechanisms have been put forward by various researchers to explain the transformation of dendrites to spheroidal morphology.
Numbers of researchers have been studied on semi-solid forming of metals by mechanical stirring.
Table 4: Hardness of semi-solid formed A356 alloy Stirring Temperature (ºC) 603 608 613 Hardness (HB) 69.6 65.2 61.3 Average Grain Diameter (µm) 94 104 146 ` Fig. 4.
Results of hardness tests and average grain diameters presented in Table 5.

The increase in gas pressure may cause an increasing number of collisions between Ti, TiN, and gas particles.
(a) The relationship between modulation period Λ (interface width, grain size) and pressure of a mixture of Ar and N2.
(a) The relationship between modulation period Λ (interface width, grain size) and bias voltage.
(a) The relationship between modulation period Λ (interface width, grain size) and substrate temperature.
Figure 6(a) shows the effects of substrate temperature on the modulation period Λ, interface width, and grain size.

Since the chemical composition of a chimney-ladder phase MnX2n-m is related to the numbers of the M and X subcells in the unit cell, the X/M atomic ratio (y) of the chimney-ladder phase is directly related to the ratio cX/cM by the following equation: 1 M X2 2 M X −       −= − = c c n mn .
Following the calculations by Imai and Watanabe [12], the size of the band gap may be altered by changing the average atomic number for semiconducting chimney-ladder compounds.
Using the VEC=14 rule for predicting the semiconducting behavior, adjustment of the group number of the M-site elements might be used to alter the VEC, producing p-type semiconductors for VEC<14 and n-type for VEC>14, with the carrier concentration related to the deviation from VEC=14 [12].
The as-grown ingot of the Ru1-xRexSiy chimney-ladder phase with x = 0.36 was a columnar-grained polycrystal, in which the [001] direction of each columnar grain is nearly parallel to the growth direction.
Fig. 3 shows temperature dependence of Seebeck coefficient measured along [001] in the case of the single crystals and along the growth direction in the case of the columnar-grained polycrystal.

The samples of glass ceramics were cut into small pieces with the size of 10 mm ´ 10 mm ´ 3 mm and polished, the number and composition of samples show in Table 1.
The composition of Na2O-Y2O3-P2O5-SiO2 system glass sample (mol%) Sample number Na2CO3 Y2O3 SiO2 H3BO3 P2O5 Sb2O3 PG 15 3 45 31.4 5.4 0.2 Fig.1.
The Fourier transform infrared spectra of the samples were taken using a FTIR-8400S spectrometer in the wave number range of 1500–400 cm−l.
The samples of heat treatment at 650°C have smaller grain size, with the increase of heat treatment temperature, the grain size increases obviously, even occurs reunion phenomenon.
This result is in accordance with the calculated results of the average grain of GC2 and GC3.

Sintered compacts generally contain some pores, new phases or dislocations at the grain boundaries, whereas there is no pore, second phase or dislocation observed at the grain boundaries of YAG ceramics, as shown in Fig.2 [2].
We can see a clear lattice image of the grain boundary.
Input power to laser medium is fundamentally determined by the number of reflectors.
YAG ceramics contains much more grain boundaries than YAG single crystal.
The dopant ions are likely to segregate at the grain boundaries.

A great number of semi-solid metal slurry forming technologies have been developed in China over the years, namely the New MIT, Cooling Slope, Twin-screw Rheomolding, Shear-cooling Roll, New Rheocasting, Near Liquidus Casting and many other processes.
The shape factors were between 0.78 and 0.86 and the grain diameters were between 48-68 μm.
It was observed that increasing the plate length resulted in an increase in the shearing action and the cooling time was prone to produce finer grain structures.
It was also observed that the primary α(Al) grains tended to coarsen and spheroidize during slow cooling.
It was reported that globular and fine grain semi-solid metal slurry could be obtained from a gas assisted stirring and vibration apparatus.

The corresponding number of the prepared sample was denoted as S1, S2, S3, S4, S5, S6, S7.
However, at 2θ (28.46°), S1 sample number have the diffraction peak of Sb2O3, which indicate that antimony powder of S1specimens have been oxidized.
To obtain nanometer-scale particles of antimony, the grain growth and aggregation should be controlled.
In this experiment, the nano-antimony powder is achieved by changing the current density and the control of grain growth.
In addition, there are not only a lot of Sb3+ ions but also H+ ions, OH-ions and a large number of free electrons in the electrolyte because the electrolyte can be electrolyzed under current function.

Recent researches have reported that ceramic composites incorporating nano-size particulate within matrix grains or at the grain boundaries possess excellent mechanical properties, even at high temperatures [7].
This is due to crack deflection and inhibition of grain boundary sliding at elevated temperatures by dispersed phase and residual stresses based on mismatch of coefficients of thermal expansion between matrix and dispersoid.
The size and number of such spherical pores as observed in composite Z-70 (ZrO2: 70%) decrease with the increase in mass % of ZrO2 (Fig. 1).
SEM micrographs of the matrices of the composites showed that number and sizes of pores decreases with increase in mass % of ZrO2.
SEM photographs showed that spherical pores of several µm in diameter were uniformly distributed in the matrices of composites; and the number and sizes of the pores were reduced with increasing the mass % of TZ-3YS.

The weld nugget consists of small grains in FSW than those found in MIG weld.
Because of this technical importance, a large number of designers and technologists have been employed to investigate and to optimize the manufacturing processes of aluminum alloys; a particular interest has been given to the welded joints [1-6].
A different structure was observed for FSW, in fact it is showed that the Thermo-Mechanical Affected Zone is characterized by recovered grains containing an high dislocation density, while in the stir zone, a very fine equiaxed grains occur due to the dynamic recrystallization [3, 4].
Finally, the microstructural analysis showed a high density dendritic structure in the weld metal of MIG due to the rapid heating and cooling of the welding zone, while a fine equiaxed grains occur in the weld metal of FSW due to the dynamic recrystallization.
Higashi, “Influence of friction stir welding parameters on grain size and formability in 5083 aluminium alloy.

And a number of double perovskite compounds have been known, where the Curie temperature can be as high as 635 K [3].
The average grain size D of the samples is 39.7, 37.1, 33.4 and 31.9 nm, respectively, which is decrease with the increasing of x for the smaller radius of Cr (61.5pm) than Fe (64.5pm).
The resistivity of these samples decrease with temperature, and shows semiconductor behavior for the existence of grain boundaries which depend on thermal scattering carriers, as commonly seen for polycrystalline ceramic samples [12].
The x-ray diffraction patterns of the samples show that the samples are in nanometer range, and the average grain size D of the samples decrease with the increasing of x.
The resistivity of these samples decrease with temperature, and shows semiconductor behavior for the existence of grain boundaries which depend on thermal scattering carriers, as commonly seen for polycrystalline ceramic samples.