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All the tested hardmetals exhibit an increase in the number of cycles until failure with a decrease in the maximum stress, i.e., the hardmetals exhibit a high fatigue sensitivity.
�Since brittle carbide grains are the primary constituent of hardmetals, the eccentricity of the test piece leads to a significant scattering in the experimental results.
The mean carbide grain size and Co content are listed in Table 1.
However, the plots are scattered, the tested hardmetals exhibit an increase in the number of cycles until failure with a decrease in the maximum stress, σmax.
Fig. 2 Mean carbide Mean flexural grain size, d WC [µm] stress, σ F [GPa] WC-4% Co 4 2.7 WC-6% Co 6 3 WC-10% Co 10 2.7 Table 1 Mean carbide grain size, Co content, and mean flexural stress of the materials under investigation.

Secondary phase particles decorate grain boundaries in this alloy.
WZ21 alloy in as cast state is characterized by almost equiaxed grains with the grain size (50 ± 8) μm.
The structure of PM alloy is more fine-grained.
Grains are elongated in extrusion direction.
Fig. 3 shows the diffraction patterns in Mg matrix zone that reveal characteristic number of LPSO reflection spots between primary and (0002)α-Mg spot – 5 for monoclinic 18-R (Fig. 3a), resp. 6 for hexagonal 14-H (Fig. 3b).

Whereas the n-Ti samples after the shot peened treatment showed manifest grain refinement structure.
Large number of distinct nanocrystalls with the size ranging from 40-100 nm with a mean value of about 60 nm was observed, and exhibited inhomogeneous distribution and clear grain boundary (Figure 1d). 3.2 Cell proliferation Figure 2 showed that the absorbance of formazan produced by viable cells adhered to titanium with surface nanocrystallization and the controls at days 1, 4 and 7 of culture, respectively.
mechanical properties and biocompatibilities that are fundamentally different from, and often far superior to those of their conventional coarse-grained counterparts[4, 5] .
The formation of nano grain is attributed to a great amount of deformation being introduced into Ti samples’ surface in a very short time.
And the original coarse grains were divided gradually by dislocation walls and dislocation tangles, etc .

The densification usually accompanies the elimination of porosity and grain growth during high temperature sintering.
In all ceramic samples can be observed that exists a large number of pores.
By the addition of 1 wt. % additives, the number of voids size decreased slightly as shown in Fig. 2(b-d).
Therefore in all micrographs there are not the grain growth rates.
Microstructural examination of sintered ZrO2TiO2 ceramics shows a large number of short porosity as is evident from Fig. 2(b-d).

The irregular micro-particles close-grained process was been analyzed under vibrating compressive.
The numerical simulation results demonstrate that the coarse-grained soil Irregular particles compacting effect of the simulation results with the actual theoretic situation in the basic line.
The Irregular particles were whirligig and movement, location of the rearrangement as a whole to show the close-grained process.
Based on the discrete element calculation results, using the post-processing system of discrete element program to obtain the elements state diagram at different times and with different numbers of compaction operations .
Stress transmission through a model system of cohesion less elastic grains [J].

As we increased the sintering temperature, the number of formation of necks between particles was also increased.
When more necks were formed between particles, it automatically reduced the size and number of pores inside the sintered parts.
When the sintered parts had a small number of pores, it become denser, and thus increased its hardness and strength.
By increasing the sintering temperature, a progressive change in the pore morphology from irregular pores to spherical pores within the grains or located at the grain boundaries.
In Figure 4, the grain boundaries were not yet formed, while in Fig. 5, the grain boundaries were completely formed due to formation of necks between the particles.

The results show that the composite coatings possessed higher microhardness and fine-grained structure.
Introduction Grain size, surface morphology and microhardness of composite coatings not only depend on bath composition, but also electrolysis conditions[1,2].
However, further increasing Toff resulted in a progressive increase of the size and number of spherical crystals, and a corresponding decrease of surrounding fine-structured matrix.
The reason is that longer Toff results in an activation of growth centres and larger grain sizes.
Fig.7 shows further refinement in grain structure at Jp of 10, 30 and 50A/dm2.

Therefore, a great number of investigations have been employed to improve their mechanical properties and corrosion properties.
The grains of all the samples are mainly equi-axed pentagon.
The grain sizes of the alloys are shown in Fig. 2b.
The average grain size of BE-state binary Mg-1.0Zn alloy is 22.1 µm [8].
Meanwhile, the deviations of the grain sizes are 2.88, 2.34, 2.53 and 3.70, respectively.

The results indicated that the addition of rare earth elements refined grain size and secondary dendrite arm spacing (SDAS), and the tensile strength was affected by means of the second-phase precipitation and the grain boundary.
Liu et al. [14] found that Ce would also refine the grain size and improve the mechanical properties of Al alloy.
With the increase of the RE, the dimples became shallow, the number increased, as showed in Fig. 6(B, C, D, E, F).
But with the increase of RE, more second phase produced and distributed around the grain boundary
Langdon, Influence of scandium and zirconium on grain stability and superplastic ductilities in ultrafine-grained Al–Mg alloys, Acta Mater. 50 (2002) 553-564

From Fig.3 (b), the grain of the original microstructure is coarse and distributed equiaxedly, the grain boundaries are straight.
When the strain was 0.01s-1 Fig.3(d), the region of recrystallization diminished compared with Fig.3(c), the grains of dynamic recrystallization grains replaced most raw grains, at the same time, the size of new grains smaller then former, the number of nucleation decreased.
Conversely, the influence of temperature on the size of grains was certain at the same strain rate.
With the Fig2(a-d), the conclusion is that the size of grain after dynamic recrystallization is inversely proportional to the flow stress, that is, the greater flow stress ,the finer grain size.
This is because in certain range, the higher temperature, the easier dislocation climb and sub-boundaries move, rotate and aggregation, which made the nucleation rate, grain boundary migration rate and the growing rate of grain increased.