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As a consequence, two fully-recrystallized material states with different grain size were obtained: fine-grained with ~10 μm average grain size (Fig. 4a) and coarse-grained with ~200 μm average grain size (Fig. 4b).
Microstructure of CuZn10, a) fine-grained alloy with ~10 μm average grain size, b) coarse-grained alloy with ~200 μm average grain size a) b) c) Fig. 5.
Upon the first minutes of the test prominent traces of plastic strain, grains uplifting and cracking along grain boundaries are visible (Fig.8 a-b).
A surface state of the CuZn10 after cold rolling and annealing at 750 ºC (a grain size of 200 µm), a),b) plastic deformation effects, c), d) the uplifting of grain boundaries zones, e), f) cavities and craters n the sample surface Additionally, results of the SEM microscopic observations revealed a large number of shear bands located near grain boundaries.
A large number of shear bands observed on surface of each sample indicate on a fatigue character of cavitational destruction. 3.

Nanostructured and ultra-fine grained metals have higher strength but extremely limited ductility compared to coarse grained metals.
The final microstructure after rolling had a grain size of 100 to 200 nm and following short annealing at 180 o C for 3 min resulted in a "bi-modal" grain size distribution in the nanocrystalline to ultra-fine grain range.
The volume fraction of coarse grains with a grain size of 1 to 3 µm was about 25%.
Considering a material with i-modal microstructures, the number of the ith-order grains with a grain size of di can be described by a power law as D i i d C N = , (1) where Ni is the number of grains with a grain size of di, C is the constant; D is the fractal dimension.
Three-grain unit cell model of MMC with the periodicity boundary conditions.

Two populations of grains were studied, one textured (large grains or templates) with volume fraction f and texture factor r and one random (matrix small grains) with r = 1.
A bimodal microstructure dominated by a large number of interconnected large and anisometric grains is clearly observed.
For unseeded ceramics under the same processing conditions, only small plate-like and well-faceted matrix grains were observed, with a maximum grain size below 15 µm [8].
However, the final number of large anisometric grains for the samples sintered for > 2 h was greater than the initial number of templates, suggesting that new large grains are formed among the templates.
It is believed that the higher number of large grains, which are introduced in the stereological analysis, are probably responsible for the increase of the r parameter for samples with 2 and 24 h of sintering time. 0 10 20 30 40 50 60 70 80 90 0.0 0.2 0.4 0.6 0.8 1.0 Experimental March-Dollase fit Normalized Frequency θ (degree) 0.01 0.1 1 10 0.48 0.52 0.56 0.60 Texture Factor (r) Log Sintering Time (hours) Fig. 3.

This algorithm can remove the dependence of computation on the number of order parameter.
The nucleation number in each grain can be expressed as follows: (8) Clearly the nucleation rate is determined by the average subgrain size and the matrix grain size of grain .
This implies that higher deformation temperature will trigger recrystallization easier and speedup the DRX kinetics due to combined effect of increased nucleation number and increased grain boundary migration rate.
The initial matrix grain size has no effect on the steady grain size.
Grain boundary curvature and grain growth kinetics with particle pinning.

With the increasing in environmental management, and people developed a number of non-cyanide silver cyanide-free solution .the cyanide-free silver-plated was tested and research by a large number of Scholars and they got some results[5-9].
Fig.2 XRD pattern at different ultrasonic power The the grain size was caculated by the eq.1.
Tab 1 shows the the relationship between ultrasonic power and the grain size.
With the ultrasonic power increasing, the average grain sizes of the silver coating significantly reduced ,but when the ultrasonic power increasing ,the grain sizes of the silver coating did not have a significantly change.
When the nucleation rate was faster than the grain growth rate, the grain had been refined[12] .

The grain sizes are about 40μm after anneal.
The number of craters after 5 pulses reaches the top, and then decreases with the increment of pulses.
Generally speaking, material properties mainly depend on a number of factors like grain size, phase composition and residual stress.
Consequently, ultrafine grains were formed on the irradiated surface.
Fig.5 The relation between the microhardness of the surface and the number of pulses Conclusion Many craters are inevitably formed on the irradiated surface, and the densities of distribution of the craters are related to pulsed numbers.

It is accepted that P segregation at grain boundaries causes the improvement in grain boundary cohesion, intergranular oxidation resistance, and grain boundary precipitation [2-4].
However, a large number of blocky or needle-like shape η phase precipitated along the grain boundaries, and few granular phosphide particles were observed at grain boundaries through EDS.
However, the η phase was distributed within the grain matrix and along grain boundaries.
The grain size was unchanged compared to the as-rolled grain structure (Fig. 1a).
For the unchanged grains microstructure, the phosphide particles stayed at the original place (Fig. 6d); for the grown grains microstructure, the phosphide particles appeared within the grain interior outlining the original grain shapes (Fig. 6e).

Effect of Silicon on the Grain Size and Grain Morphology of AZ91E.
The grain size measurements were based on two samples and a minimum of 100 grain measurements was taken across each sample.
The average grain size of AZ91E was 103 ± 25 μm.
Effect of silicon on the average grain size of AZ91E.
The dendrites in the unrefined alloy are large and highly branched, while the grain structure in AZ91E with Si additions consists of smaller, less developed (less number of secondary dendrite arms) dendrites.

In the presence of lutecium (a), the diametrical growth of the silicon nitride grain is faster than when lanthanum (b) is present, resulting in low aspect ratio grains.
Combined with the greater preference of La for residing at the silicon nitride grain surfaces, these can be taken as mechanisms for limiting diametrical grain growth resulting in high aspect ratio grains when La is one of the components of the sintering additives.
With increase in creep strain, one observes an increasing number of these elongated grains that either contain cracks or are fractured.
As a result diametrical grain growth is impeded and elongated grains, which are desired to toughen the ceramic, are formed.
Rühle, "Grain Boundary Films in Rare-Earth-Based Silicon Nitride," J.

Micrographs were analyzed using standard image analysis software (KS 400, Kontron Electronics GmbH, Germany) to determine mean grain sizes and grain size distributions.
In consequence different microstructures were developed in each case: in particular the mean grain sizes, and grain size distributions differed.
The fracture toughness of the pure alumina (A3, 3.4 MPa.m1/2) corresponds at the mean grain size of 3.7 µm to MgSiO3-sintered alumina with 10 wt. % of silicate, and a similar mean grain size.
Further analysis revealed that the grain size distributions of all examined materials could be also described by a lognormal distribution function and the mean grain sizes and the grain size distribution widths were estimated by non-linear regression.
Acnowledgement The financial support of this work by the NATO Science for Peace Pprogramme, Project Number SfP-974122, and by the Slovak National Grant Agency VEGA, under the contract number 2/3101/23, is gratefully acknowledged.