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AZ grain is produced by mixing alumina grains with zirconia grains of 30%wt., which is about 1300 in knoop hardness [4].
And the stock removal with AZ grain is larger than that with WA grain that is similar to that with GC grain.
That is, the interference intensity of GC grain is larger than of WA grain because of higher hardness of GC grain.
AZ grain acts on the workpiece surface stronger than WA grain, as the result that AZ grain including zirconia abrasive is softer than WA grain but its specific gravity is larger than that of WA grain.
The number of acting abrasive grain on the workpiece surface is estimated to be proportional to the abrasive concentration, but stock removal at 30%wt. is remarkably larger than those at other concentrations.

In this area, the grains are elongated towards the surface.
The size of coherent-scattering region X-rays of the grains of the c-ZrO2 phase is 15–20 nm.
The total number of pulses was N = 100 and 300.
It is seen that the shape of the grains in the melted subsurface region and that of the grains in the sample volume are radically different.
In the surface layers, the grains are oriented towards the surface to be treated.

It can be seen that the microstructure under different solution temperatures are of equiaxed grain structure, and that the grain sizes increases with increasing solution temperatures.
The grain boundary mobility increases with increasing temperatures, which resulted in the increasing grain sizes with increasing solution temperatures for this metal matrix composites.
It can be seen that the microstructure under different solution temperatures are of equiaxed grain of different sizes, and that the grain sizes increases with increasing solution temperatures.
The formation of refined grain sizes should be due to higher energy storage caused by more severe deformation, which is benefit for the forming of more nucleus and more refined recrystallized grains.
Acknowledgement It is a project supported by natural science foundation of shanxi province China (project number: 2011011021-1).

Recently, a large number of researches focus on Bi0.5Na0.5TiO3 (BNT)- and K0.5Na0.5NbO3 (KNN)- based lead-free piezoelectric ceramics[2].
To improve its piezoelectric properties, a large number of BNT-based solid solutions, such as BNT-Bi0.5K0.5TiO3 [4], BNT-NaNbO3 [5] and BNT-Bi0.5K0.5TiO3-BaTiO3[6], have been studied intensively.
Obviously, a preferred grain orientation of (h00) happened.
The vacancy and chemical deviation would hamper the orientation of grains.
In the early period, a large number of grains with a small size could be observed except for some templates with a large size, which proved that the growth of matrix powders along the templates did not take place sufficiently.

SEM micrograph showed the Jc is induced significantly by continuity of grain formation via grain size.
The doping of alkaline-earth metal does not just increase the number of holes in the CuO2 planes, but reduces the current blocking effect of grain boundaries [2,3].
Larger grain size will enhance the grains continuity, lessen the porosity thus enhance the Jc value.
Bigger grain size, minimum porosity and less of grain boundries is also founded with Y123 system.
The existence of impurities (Ca) and the continuous formation of the grain decrease the number of grain boundaries.

Wetting of nanoparticles by liquid aluminium presents a number of challenges.
A number of techniques have been used to incorporate nanoparticles into molten aluminium.
Grain refining was accomplished using 5TiB master alloy to achieve a level of 40 ppm B in the melt.
Most particles and particle clusters remained at the grain boundaries.
Conventional grain refining improved tensile, yield and elongation values.

Meanwhile, the crystalline grain had a uniformity distribution, and the grain size was about 9.5~10 grade.
When the tempering temperature rose continuously to 640℃, a large number of supersaturated precipitation carbides happened along the grain boundaries, and began to gather and grow forming black network microstructure, as shown in Figure 4(c).
The most numerous of these precipitates were needle-shaped type, while a smaller number of precipitates were club-shaped type.
On the other hand, yield strength of HSLA steels has reached 780MPa [2], which were contributed to the large number of carbide precipitation distributed finely and uniformity.
Consequently, the reduction in the number of M3C carbides leads to an improvement in the fracture toughness [6].

Image analysis techniques which can discern individual `grains' (the circular Hough transform and the ImageJ particle analyser) were used to evaluate the grain size distribution from SEM images.
(a) ImageJ analysis: grain outlines (b) ImageJ analysis grain size distribution Fig. 6: CuO thin film crystallite size analysis using ImageJ.
A number of image analysis techniques can be used to extract size distributions from high resolution SEM images.
It is surprising to observe thermal activation behaviour in such a highly disordered film, comprising a large number of grain boundaries.
This result is perhaps surprising given the extremely large number of grain boundaries and associated defects that are found within our sample.

On the other hand, the number of under-3um Al-Fe-Si particles at outside surface was much than that at inside.
The number of over-3um and low-aspect- ratio particles was almost same.
Black lines are large angle grain boundaries >15°.
Cube grains were observed under small cracking area.
Black lines are large angle grain boundaries >15°.

For the extrusion speed of 0.2mm/s, the microstructure of extruded Mg rods was composed of equiaxed fine dynamical recrystallized (DRXed) grains and some elongated coarse un-DRXed grains.
On the one hand, higher extrusion speed not only enhances the nucleation of DRX grains but also shortens grain growth time and thus benefits to grain refinement [14,19].
The repeated number of the tensile testing specimens for every extrusion speed was three.
When the extrusion speed was increased to 4.0mm/s, as shown in Fig.1(c) and (f), the DRXed grains in the extruded high-purity Mg rod were remarkably coarsened and the elongated coarse un-DRXed grains vanished.
The following main conclusions can be drawn: (1) The microstructure of high-purity Mg rods extruded with extrusion speed of 0.2mm/s composed of equiaxed fine DRXed grains and some elongated coarse un-DRXed grains.