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Some researchers [12-13] thought that the increase of supercool for nucleation would increase nucleating rate resulting in the grain refinment.
When the temperature was high enough, the atom number of the atom cluster with the biggest size in Al melt basically tended to a constant, and hardly changed with temperature.
Thus grains again grow up by the action of the interface curvature and interface energy.
Hence, it can be drawn a conclusion that the optimum superheating temperature is 860°C and the suitable isothermal holding time is 25min, in which there are the fine grains in the alloy by melt superheating, during this research.
The finer the size of grain is, the more amount of grain on the unit area to cause the greater resistance against deformation, thus the hardness of the alloy is raised so that the resistance of the alloy is improved finally.

For the achievement of accurate material equations, three different aspects must be taken into account for testing superplastic specimens: the strain rate sensitivity, the grain size evolution and the cavitational evolution.
A number of researchers have examined the effect of stress state on cavitation [1-4].
In the case of the constitutive equations presented in this paper, the strain rate sensitivity vs. strain rate curve is dependent on the strain rate, strain, grain size, isotropic hardening and cavitation fraction.
This equation set takes into account grain size hardening, isotropic hardening and void area evolution, and the constitutive constants have been obtained from controlled constant strain rate tensile tests.
Dunne, "Modelling grain growth evolution and necking in superplastic blow-forming," Int.J.Mech.Sci. 43 (3), 595-609 (2001)

The thin films can be deposited by a number of different techniques such as sputtering, metal chemical vapor deposition (MOCVD), pulsed laser deposition (PLD) and sol-gel method [8].
Based on Fig. 2 (a), (c) and (d), they have non-uniform grains and relatively rough surface.
However, for Fig. 2 (b) and (e), we can see that the surface is quite smooth and more uniform grains.
The AFM result revealed that Gd concentration which is 1% and 8% has a quite smooth with fine structure and uniform grains.
However, for 0%, 2% and 4%, they have non-uniform grains and relatively rough surface.

The cooling speed is the important factors to decide the microstructure and grain size of the experimental steel [6-9].
For observation of the grain structure, the polished samples were etched with 4% Nital.
Proeutectoid ferrite firstly precipitated at the grain boundary of the original austenite.
The nucleation position and nucleation rate of ferrite increase, and the effect of grain refining is strengthened.
The letters beside the cooling curve are on behalf of the cooling rate and those numbers below the cooling curve are the values of Vickers hardness （HV0.2）.

Fine ground recycled concrete was used as a filler with certain bonding properties of nonhydrated cement grains in FGRC.
To obtain the best images from the microscopy the samples were gradually grinded and polished on the machine Struers LabPol – with 5 of sandpapers with fineness of 300 grains/cm2, 500 grains/cm2, 1200 grains/cm2, 2400 grains/cm2 and 4000 grains/cm2.
The following conclusions were determined from the results presented in this article: · The largest shrinkage affected by the largest number of pores were found in the samples of cement mortar with 67 wt. % of FGRC

Synchrotron radiation micro-beams are more suitable to illuminate a small number of grains and modern image detectors are able to record the diffraction patterns in real time to observe the structural evolution in situ [7-9].
With a monochromatic beam, the individual grains deliver diffraction spots when the Bragg condition is fulfilled, and each spot is a diffraction image of grain carrying information about the size and sub-microstructure.
The development of diffraction intensity in high-energy X-ray diffraction is corresponding to the growth of grains or the disappearance of grains [10, 11].
Results and Discussion The diffraction intensity of Debye-Scherrer rings is homogenous when the orientation of grains in polycrystal distributed randomly.

Molybdenum can obviously improve the hardenability of the steel and heat resistance, grain refinement, purify grain boundaries, to prevent the temper brittleness, remanence and coercivity increase.
See Table 3 for the process number.
Table.5 The impact toughness values in different conditions number AK/J αK/J/cm2 1 33.28 41.62 2 48.31 60.04 3 32.65 40.07 4 31.34 39.43 Contrast analysis on the mechanical properties.
According to the relation of conversion between hardness HRC and hardness HB, ( HRC ) = HB /10-3, the hardness value of the number.1 is 13.2HRC, the hardness value of the number.2 is 9.8HRC.
Cross coordinate graph represent different process number, the ordinate represent the change impact toughness.

Kandala et al [7] have reported the use of a small parallel-plate capacitor in the measurement of the moisture content in single grains of corn non-destructively, in which the capacitance of a small parallel-plate capacitor with the grain between the plates was measured.
Further studies by the same authors revealed that use of the complex impedance of the parallel-plate capacitor loaded with a grain measured at two frequencies, 1 and 4.5 MHz, provided sufficient information to predict the moisture content of single grains independently of their shape and mass [8-10].
Moisture contents of individual grains were predicted to within 1% with these techniques.
The same technique was later used in the measurement of the moisture of grains of peanuts [11-12], popcorn [13] and pecans [14].
Where a is amplitude;α, real, is the wave number; and α π λ 2 = is wavelength; β is complex (i.e.

The array was, in effect, a fine-grained replica of the original spatial arrangement of the spheres.
This procedure has been used many times in related problems, especially in connection with grain boundary diffusion, see, for example, ref. 19.
The diffusivities were scaled directly to the jump frequencies from site to site in each phase, time was scaled to the number of jump attempts of a particle.
On the other hand, as mentioned above, other Monte Carlo studies [15-17] have shown that the MaxwellGarnett Equation does not do so well when the dispersed phase is represented as squares or cubes as might be used as a primitive model for grains surrounded by wide grain boundary regions in nanocrystalline materials.
Gust: Fundamentals of Grain and Interphase Boundary Diffusion, (Wiley, Chichester, 1995)

In the bearing steel, Cr is the element that easily forms nitride; the segregation leads to be rich in Cr on the grain boundary.
A number of spherical V (CN) existed between upper pair and underneath pair, it absorbed more energy to improve the carrying capacity of bearing steel and reduced bump contact between the friction pairs.
In addition, vanadium can inhibit the growth of austenitic grain and refine the grain size.
This was because the decrease in nitrogen potential lead to the inhibition of nitrogen diffusion along the intracrystalline diffusion reduced, and then nitrogen mainly diffused along the grain boundary, which promoted the combination of chromium and nitrogen at the grain boundary.
On the other hand, the types of deposition grow in number after the strong permeability for a long time.