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The grain size of sample 2# which sintered at 1273 K is about 370 nm~1.5 μm.
When the sintering temperature increased to 1373 K, the grain size increases slightly to 550 nm~2 μm.
Moreover, it should be noted that the number of elongated grains and the degree of elongation in elongated grains increase with sintering temperatures.
The elongated grains may improve some properties of CuAlO2, which enable them have wider applications.
It is found that, as the sintering temperature increased, the grain size of the samples increases as well as the degree of elongation in elongated grains.

Structural relaxation effect of the diffusion coefficient has been observed in the grain-boundary region of the alloy.
A number of studies have been done on selfdiffusion as well as impurity diffusion in nano-crystalline alloys in recent years [1,2,3,4,5,6,7,8].
It is found that the grain-boundary diffusion in nanometals is similar to that in conventional polycrystalline metals.
Also, electron microscopy and Mössbauer studies suggest that grain-boundary structure in nano-metals is similar to that in conventional coarse-grained poly-crystals [9,10].
Annealing of the nanostructured phase results in grain-boundary relaxation towards equilibrium phases.

Due to the high density of interfaces and grain boundaries present in the nanocomposites, the scattering of phonon across a broad wavelength spectrum was enhanced.
PPP disperse in the matrix evenly, locating not only on the grain boundaries, but also inside the grains.
The electron of low energy (with small relaxation time) is filtered by such extra potential, leading to a local increase in electron number at the Fermi level [13, 14].
Due to the high density of interfaces and grain boundaries present in the nanocomposites, the scattering of phonons across a broad wavelength spectrum was enhanced.
Due to the high density of interfaces and grain boundaries present in the nanocomposites, the scattering of phonons across a broad wavelength spectrum was enhanced.

It indicates that Co2O3 in the ceramic acts as flux because of its low melting point (900°C) and some pores occur in the grains if its content excesses 2.4wt%.
The main grain phases are Mg2TiO4 and Mg2SiO4.
Additionally, minor grain phase MgO occurs because Mg 2+ is replaced with Co2+ in Mg2TiO4 to form (Mg,Co)2TiO4 solid solution and MgO educts.
Acknowledgements This work was supported by the National Science Foundation of People's Republic of China under grant number 50172035, and the '863' High Technology and Development Project of Peoples Republic of China under grant number 2001AA325110.

Table 1 shows the list of these powders, including the number 0-20 vol% of CBN, and the number 8 wt% of Co added to the hard metal matrix.
A micrograph from a fractured surface is obtained (Fig. 3 (b)) in order to reveal the morphology of the CBN grains.
At the temperature, a submicrometer grain microstructure, without a pronounced grain growth.

However, owing to boundary segregation and coarse dendritic grains, typical cast aluminium alloys have low hardness and strength, limiting their use in large-scale and complex-shaped applications.
The composites' grain structure demonstrated a uniform distribution of reinforcing phase of Al 6063 Alloy.
A fine-grained emery polishing paper was used to produce the micro-hardness samples (see Fig. 6).
The images demonstrate that the reinforcement in the matrix of Al 6063 alloy enables grain refinement.
Additionally, the grain microstructure of the composites showed that the reinforcement was distributed evenly throughout Al 6063 Alloy's matrix.

This occurs because the nature of PL is such that an improvement in the number of carriers (electron and holes) results in enhanced PL intensities.
Higher deposition power appeared to increase the ratio of Si atomic concentration and, hence, an increasing number of silicon nanodots.
Results and Discussion In all samples, the grain sizes are uniformly allocated on the surfaces of the substrate as shown in Fig. 1 (a) for the samples grown on quartz substrate at temperature 600 °C, RF power 100 W and deposition time 10 min.
It is noticed that as deposition power increases, the number of nanodots also increases.
The higher deposition power seems to cause an increase of ratio Si atomic concentration and, hence, an increase of silicon nanodots number.

The interface usually has a wavy shape with characteristic increase of hardness and largely deformed grains.
Transcrystalline cracks were in the majority of observed cracks, but grain boundary cracks were also noticed.
Fatigue tests results, a) steel-titanium bimetal – strain amplitudes εa relation to total number of cycles to failure Nf, b) titanium Grade 1– stress amplitudes σa relation to total number of cycles to failure Nf Summary Summarizing performed experimental research on titanium Grade 1 and explosively welded steel-titanium bimetal, following conclusions are drawn: (i) ratcheting and cyclic instability were observed during bimetallic specimens fatigue tests, (ii) titanium Grade 1 do not exhibit ratcheting phenomena, (iii) softening of the bimetal and hardening of titanium specimens were observed, (iv) investigation on titanium Grade 1 fatigue properties and their influence on bimetal properties require further researches.
Decision number: DEC- 2011/03/B/ST8/05855 References [1] F.

Mesh generation method For convenience, we use tetrahedral grids to construct the modal, and assume that several grids form a grain for a given porosity, also the spatial distribution of the solid skeleton is completely random.
The steps are first generate the tetrahedral grids, then several grids form one grain, finally specify the physical parameters to each particle randomly.
Fig.4 shows the influence of the number of grids on the computation error.
Fig.4 (a) shows that the relative error decreases with the increase of the number of grids; although there are a decreasing trend in the relative error, the changes are relatively flat with the increase of the number of grids when the grid number is greater than 10 million; the relative error of Keff is 0.0078% when the number of grids is 15 million, which also verifies the reliability and correctness of the program.
As shown, the critical value that the number of grids affects the errors is about 1×105.

In the process of low-load fatigue, the shape and distribution of MMMT signal curves are similar under different cycle numbers of fatigue load.
The value of MMMT signal increases a little with the increase of cycle number of fatigue load, and then increases sharply when the specimen is to be fractured.
Analysis[3,4,5] (1)When the load is small, in the uniaxial tensile load, the specimen is not up to the sliding grain critical stress to produce dislocation pile-up, so magnetic memory signal has a little change.
After Specimens yielding, the grain in the right direction slides, a large number of dislocation pile-up occurs, and then dislocation density increases.