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The experimental results indicated that a large number of spherical silicon oxides were dispersed as amorphous state, and the size range was in hundreds nanometers.
The formation of oxides during sub-rapid solidification, which could be favorable to attain grain refinement to enhance the strength of steel, has attracted a lot of attention.
Table 1 Oxygen contents, thickness of copper mold and cooling condition of A1, A2, B1, B2 Sample Number [%O]/ppm Thickness of Copper Mold/mm Cooling Condition A1 59.8 9 water cooling A2 52.4 9 air cooling B1 49.6 5 water cooling B2 50.6 5 air cooling The chemical compositions of solidified as-cast steel are respectively shown in Table 2 respectively.
Table 2 Chemical compositions of alloying elements by compound deoxidation (mass fraction, %) Element Number C Si Mn Ti Ni S P A1 0.022 0.0531 0.264 0.0124 0.0118 0.0178 0.0115 A2 0.0248 0.0534 0.257 0.0152 <0.0050 0.0187 0.0105 B1 0.0763 0.0476 0.261 0.0129 0.0073 0.0229 0.0192 B2 0.0254 0.0468 0.265 0.0117 0.0061 0.0166 0.0127 Results and Discussion Amorphous silicon oxides in the sub-rapid steel.
The solidification rate must be large enough to inhibit the grain generation and growth, and the critical solidification rate mainly depends on the grain’s nucleation capability and growth kinetics.

The valorization of dredged materials and their use in road pavement and in construction is a topic that has attracted the attention of an increasing number of researchers in recent years [12–17].
The grain size distribution is used for sediment classification according to the French guide GTR (LCPC-SETRA-92) [33].
When water is added into a dry mixture, each grain is first covered with a water film.
The results of the particle size analysis showed that the largest portion of grains had a size less than 1mm.
The amount of grains with size equal or less than 63 μm was about 97% by mass.

Explosion welding has produced a large number of dissimilar joints.
Due to the high hardness, 65-70 HV, of the as-received AZ31, a prewelding annealing was done at 450°C to reduce the hardness and improve the grain structure homogeneity and capacity for plastic deformation.
Marya et al. [15] reported that heating of work-hardened AZ31 to 450°C followed by rapid cooling, could lead to formation of single phase fine recrystallized grains and an increase of microhardness to 96 HV.
Considering the time scale of the welding process, it is presumed that such a thermal cycle induced grain refinement in the material near the interface.

SMG has many advantages of high temperature, salt tolerance, shear resistance, controllable grain size, good control and oil displacement effect.
The projection area of each particle is calculated, according to the principle of equivalent projection area of each particle size, and then the number of particles in the certain area is established statistically.
SMG microgels are the new kind of deep profile control agent used in many oilfields, which has many advantages such as high temperature, salt tolerance, shear resistance, controllable grain size, good control and oil displacement effect. 2.
Development and applications of grain size analysis technique [J].

Tribology and Self-repairing Nature of RE Nanophase Composite Material Guo Ze-chenga, Chen Ming, Zhao Dong-bo, Zhang Fei-meng Hefei New Star Applied Technology Research Institute, Hefei, AnHui Province, P.R.China a15005603968@126.com Keywords: RE; Nanophase composite material; Frictional wear; Self-repair Abstract.RE nanophase composite material between the grain size 30nm and 100nm are prepared by the method of mechano-chemistry，in which the material’s adsorptive capacity to metal base is checked，and the nature of anti-friction as well as self-repairing effectiveness to the surface of abrasion is tested by four-ball friction wear testing machine.
Domestic scholars made a number of fruitful results.
This is because of the strong chemical activity of rare earth element, atomic radius, electronegative low, the low solid solubility on the surface, the strong adsorption ability at the grain boundaries, the enrichment on the friction surface.

Several experiments for compaction of tungsten amorphous powder with a mean grain size about 5 microns were performed using C4 explosive with a detonation velocity about 8.2 km/s.
An assumed compaction setup shown in Fig.1 was used for simulation of the process and by using computer simulation results an optimum setup was designed and several explosion tests were performed for compaction of tungsten amorphous powder with 5 microns mean grain size by using C4 as an explosive material.
Experimental Procedure As shown in Fig.2, using the results obtained from the simulation model, an optimum experimental setup for the explosive compaction of the tungsten powder was designed and a number of tests were conducted.
The amorphous tungsten powder with a mean grain size of 5 microns was prepared and placed in the powder container.

SEM images showed that the grains were well defined with highly dense surfaces makes it potential as an electrolyte material in solid oxide fuel cells (SOFCs) or gases sensors.
The atomic radii trend is in the order Sm>Mg=Zr>Fe in 6-coordinate while Sm>Mg>Zr>Fe 8-coordination number [19].
The grains are well defined.
SEM revealed packed surface with connected grains and no obvious porous was found.

The numbers in the figure show positions where electron-diffraction patterns were taken and EDS analyses were performed.
The surface is covered by large TiO2 grains with a size of 300-500 µm.
Beneath the TiO2 outermost layer, fine grains with the size of 100 nm or smaller can be seen and the grain size becomes larger toward the inner part.
The EDS results indicate these grains to be oxides, α-Al2O3 or TiO2.
This layer consists of relatively large and near-columnar grains, such that one grain occupies almost the entire layer thickness.

The phases to be considered are the liquid solution and a large number of solid stoichiometric compounds.
Within the grains the diffusion coefficient was supposed to be isotropic.
For the simulation a mesh of 36 grains was used.
Increasing the alloy grain size leads to decreasing inner oxide layer thickness, because the density of grain boundaries yields to a decrease in the supply of oxygen to the oxide / substrate interface.
Experiment Simulation grain size = 10 µm Fig. 10.

However, since hot deformation behavior and microstructure evolution of 2297 alloy is not well understood, there are still a large number of difficulties in the production of hot rolled 2297 plates.
A large number of dislocations are annihilation and rearrangement and enhanced the softening process.
When the strain rate decreased to 0.1s-1 at 420℃(Fig. 4(d)), some sub-grain structure were clearly observed.
As the strain rate decreased to 0.001s-1 at 500℃, the recrystallization grain was growth by merging.
Grain boundaries became more straight and clear, equiaxed grains with larger angle boundary formed, as shown in Fig. 4(f).