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It could be observed that the whole drill surface is covered with a continuous layer of diamond films with grain size of 2–3 μm.
In drilling CFRP, the tool wear of WC-Co tool is mainly attributed to the abrasive action of carbon fiber as well as fractured WC grains.
The wear is measured during the cutting tests and the results are plotted in Fig. 5 as a function of the number of drilled holes.
The SEM study presents a continuous layer of fine grained diamond films, with grain size of 2–3 μm, covering the drill surface.

Single crystal has no internal boundary, therefore grain boundary strengthening and fragment rotation of a specimen (under strain less 3%) are missing, [3], and single crystal was chosen as the simulation object.
Change rate of the critical shear stress in each slip system is defined as the hardening function sum: , (1.6) where m is number of hardening mechanisms, are of m-th hardening mechanism parameters. 6.
In the investigation [4] the result of influence single crystal grain orientation to the inelastic deformation and the localization deformation in specimens is introduced.
The diagram of rated operating conditions, dimensions in mm; indexes are denoted grain face orientations The diagram of rated operating conditions (punches and single crystal specimen) in Fig. 1 is introduced.
Characteristic dimension of the finite element corresponds to the average grain size in polycrystalline metals – about 100μm.

The light gray parts are the sea (width of 0.2 to 0.8 µm) and the white parts are the pancake ice (width of 0.2 to 2.0 µm) and the sea contains a number of beaded black spots (diameter of 0.05 to 0.3 µm).
It can be seen in this figure that a layered Pt-Ti(-Au)/Au-(Pt-Ti) alloy flat grain, corresponding to pancake ice, was losing contact with the n–-type layer because of the interposition of a thin TiO2 layer and that the black spots were actually pillars of TiO2 formed in the sea region, which weakened the electrical linkage with the nearby grains.
This degradation can be well interpreted by simple kinetics whereby the Ti contact material reacted with ambient oxygen coming from the surface, diffused along the Pt-Au (more precisely, Pt-Ti(-Au)/Au-(Pt-Ti)) grain boundaries and then changed into insulating (or semiconductive) TiO2, resulting in large series resistance.
Outward diffusion of Ti along the Pt-Au grain boundaries was also observed [6].

While both wafers are essentially free from major defects, the wafer in Fig. 2, left, shows the residual "mottled" contrast, which is due to the minor sub-grain mosaic structure in the right-hand part of the wafer.
In addition to individual dislocations, the map in Fig. 3, right, also delineates the boundaries between slightly misoriented sub-grains.
Detailed x-ray measurements performed using a highresolution Philips double-crystal diffractometer showed that the degree of misorientation between such sub-grains is below 20-30 arc-seconds.
The "mottled" cross-polarizer contrast visible in some wafers is due to the minor sub-grain mosaicity.
X-ray rocking curve topography performed on a number of the 100 mm 6H SI substrates showed a relatively small lattice curvature with edge-to-edge  between 0.1° and 0.3°.

Since 1986, microwave irradiation as a heating method has found a number of applications in chemistry [15].
Clearly, microwave heating produced a product with a much smaller and more uniform grain structure as shown in Fig. 2(a and b).
The variation of grain size was from 700 to 900 nm in Fig. 2a and from 50 to 200 nm in Fig. 2b.
Obviously, the rapid heating should be responsible for the finer grain size since grain growth in ceramics was a function of both the peak sintering temperature and its soak time.

Besides, it can be seen that the number of the pores in the samples with BCu addition is decreased.
Moreover, the grain boundaries of the samples with large content of BCu become blurred.
As it is known that the overall conductivity of a material is composed of the contributions of grains and grain boundaries.
And the liquid phase is deposited at the grain boundaries during the cool process, resulting in higher resistivity in grain boundaries, which also leads to the decrease in LSCN conductivity with increasing dopant of BCu.
It has reported that the existence of grain boundary and impurity in microstructures would lower the value of TCR [28, 29].

Optical continuity of the bars reveals that each chondrule contains a very small number of dendritic crystals.
It is mainly composed of taenite and troilite irregular grains with deformation lamellae.
Analysed troilite grains reveal iron-sulphur atomic ratios always close to one, the FeS ideal formula.
Either as single-mineral or as aggregates of Fe-Ni alloy + troilite ± chromite ± wustite, the shapes of opaque grains usually suggest that they are interstitial relative to the crystals of silicate minerals.
(c) SEM image of a sector of the barred structure, showing the alternation of olivine (blue) and plagioclase (red) and the presence of very small grains of apatite (yellow).

The equipment parameters such as the shape, number of coils, coil dimensions, distance between the coil and pipe and frequency are fixed during the induction bending process.
Besides dispersion hardening, niobium has an added benefit on the refinement of the ferrite grains.
In the coarse grain region (CGR) of the HAZ, at the tangent end (Fig.4a), the microstructure was a bainitic ferrite matrix with poligonal and quasi-poligonal ferrite.
Tempering heat treatments promoted grain refinement, MA decomposition and precipitation [3, 8] which explains the observed toughness improvement (Fig.2).
The grain refinement, MA decomposition and precipitation, within the HAZ promoted by tempering at 6400C, increased toughness values by 68% when compared with the HAZ at tangent end.

The Curie temperature, TC of the nano-Pd-H2 system miscibility gap is lower by 135 K than TC for the coarse-grained Pd-H2 system [19].
Numbers beside data points indicate the crystallite size of the β-MgH2 phase [22].
At the same time the proton spectrum of coarse-grained PdH0.7 has only a single line (peak A).
The hydrogen diffusion peculiarities with account of grain boundaries effect are theoretically discussed in detail in reviews [26,27].
However, all peaks shift to the left and their broadening as a result of decreasing grain size and strain availability is very significant.

The results also indicated that raising the metal content of the cermets also promotes grain growth.
It was seen that the cermet have a large number of small grains with diameter less than 2μm, and few block grains with diameter greater than 5μm.
The results also showed that the small grain in A, B and C samples is polyhedral particales, and the small grain in D sample is spherical particles.
As shown in Fig. 7, there are two different forms of grain in samples: one is in large block, and the other is in small particle.
ZrO2 ceramics during the sintering process is the crystallization of the crystal growth process again, generating more uniform grain size.