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The grain size of CVD-SiC(C) is bigger than that of CVD-SiC(N).
Methyltrichlorosilane (CH3SiCl3 or MTS) has been employed frequently to deposit SiC because of the same number of silicon and carbon atoms in one MTS molecular and thus it is easy to prepare stoichiometric SiC [15-19].
Fig.5 Grain size of CVD-SiC(C) and CVD-SiC(N) calculated according to Scherrer formula.
As can be seen, the grain size is 54nm in CVD-SiC(C) and 46nm in CVD-SiC(N).
The grain size of the CVD-SiC(C) is always 6-7nm bigger than that of CVD-SiC(N).

In turn, the Elektron 21 alloy before the modification contained grains of both dendritic and cellular morphology and only grains of cellular morphology after the modification.
The measurements of size and shape of the grain in tab. 5 and 6.
WE43 - mod. acc. to MEL WE43 - mod. +50% WE43 - mod. +100% grain size area of flat section A [µm2] 1706 534 442 293 number of grain per unit area NA [mm-2] 570 1841 2222 3336 relative area of grain boundary SV [µm2/µm3] 0.066 0.104 0.110 0.131 heterogeneity of the grain size variation coefficient A ν(A) [%] 72 111 121 143 grain shape shape factor ξ - 0.553 0.647 0.666 0.680 elongation factor δ - 1.62 1.70 1.68 1.66 Table 6.
E21 - mod. acc. to MEL E21 - mod. +50% E21 - mod. +100% grain size area of flat section A [µm2] 2987 459 421 452 number of grain per unit area NA [mm-2] 328 2138 2328 2171 relative area of grain boundary SV [µm2/µm3] 0.045 0.118 0.120 0.113 heterogeneity of the grain size variation coefficient A ν(A) [%] 99 92 101 101 shape factor elongation factor ξ - 0.642 0. 622 0. 617 0. 624 area of flat section δ - 1.65 1.67 1.71 1.66 The fractographic investigations revealed the existence of non-metallic inclusions on the surfaces of fractures.
The size of the grain decreases along with the increase of the amount of modifiers, apart from the +100 modification variant, with which the size of the grain insignificantly increases.

As pointed out by Gao et al. [8], however, a limited number of reports have presented data on the wear behavior of HPT-processed materials and many of these results appear to be conflicting [9-12].
The grain size was about 15 µm.
The number of turns (N) was varied in five conditions: N = 1/8, 1/4, 1/2, 1, 2, and 3 turns.
It can be seen that the grain sizes for the specimens of N = 1/8 and N = 3 were 1.0 and 0.2 μm, respectively.
The grains were significantly refined with increase of N and r.

The quality of the steel depends on additional factors which cannot be deduced from its grade number, e.g. the manufacturer and the processing route comprising smelting and melting, final annealing and the treatment of semi-finished products.
In a great number of cases, the short life of dies from tool steels is often the consequence of inadequate thermomechanical treatment.
The values in fine-grained areas were almost 40 HV3 higher than those of coarse-grained areas.
The parameter value is obtained by dividing the time, over which the part cools down from 800 to 500 °C, by the number 100.
The weakening of the boundaries of grains is also evident from the manner of crack propagation: cracks propagate along grain boundaries in the so-called intergranular fracture (Fig. 8).

The particle is W7 AI2O3 with primary mean grain size of 6.3μm.
Results and Discussion Fig.3 and 4 show the variations with grains size of the total number and active number of particles in two-body machining, respectively, in grinding zone.
The active particles number with grain size shows a similar trend.
Wheel workpiece nozzle Abrasive slurry Fig.2 The set-up diagram of abrasive jet machining Fig.3 Variation of the number of particles in grinding zone with grain size Fig.4 Variation of the active particles number in grinding zone with grain size Fig.5 Compared diagram in theoretical and actual material removal rate Fig.5 shows the theoretical and actual MRR.
The total number of particles and active particles number models in grinding zone were founded and simulated.

Cr carbide precipitates at the grain boundary, and some of particles distribute continuously on the grain boundary after service.
The continuous precipitates in grain boundary and dislocation lines in the grains can be observed in a trigeminal grain boundary region, and the particles of each precipitate are very fine, as shown in Fig.7 (a).
In another zone of the sample, a large number of dislocation lines and dislocation entanglement areas and twins can be observed, as shown in Fig. 7 (b).
According to the relevant research [8], the stress-induced strain will increase the density of matrix dislocations and produce a large number of nucleation zones, and fine NbC precipitates from the matrix, especially in the places with dislocations.
Fine NbC precipitated in the crystal can increase grain strength, and more plastic deformation is concentrated on the grain boundary.

It is shown that friction stir welding provides a fine-grained structure of the weld.
The weld zone of Al-Cu alloy consists of equal size grains, with intermetallic particles located along the grain boundaries.
Along with the above features of second-phase particle distribution, the weld structure contains a small number of voids up to 2 to 20 µm in size (Fig. 4) whose formation is related to a vortex-like flow of the material.
The structure of metal in the AMg5 alloy weld is inhomogeneous (Fig. 7): it is more fine-grained near the base metal at a depth of about 100 µm, followed by a band with coarser grains (indicated by arrows in Fig. 7,a), and then becomes fine-grained again.
Acknowledgements This research was carried out under project number 02.G25.31.0063 of Ministry of Education and Science of the Russian Federation (Resolution No.218 of the Government of the Russian Federation).

Introduction Fabrication of sheets out of coarse-grained Al alloys with equiaxed grains and isotropic mechanical properties is a complicated task due to both the texture formation and elongation of grains during rolling.
In this case one can expect the development of grain-boundary sliding retaining equiaxed grains.
ECAP was conducted with the number of passes n=10 at a temperature of 370°С and a traverse speed of ∼ 6 mm/s.
The mean grain size was calculated according to dark-field images.
Results The initial billets out of 1421 alloy had elongated grains up to 70 µm with 20 µm in cross section and with the S-phase particles (Al2LiMg) [6,7] with the mean grain size 5 µm and a volume fraction ≈ 6 % located mainly along grain boundaries.

In the 1970s, Bailey et al. had classified the different diamond grain wear forms, which consist of grain wear, grain broken, grain pullout and bond broken [3,4].
(a) The hexagon or quadrangle exposed area grain; (b) The fracture grain; (c) The covered grain; After the tool wear.
(a) The attrition wear grain; (b) The part fracture grain; (c) The whole fracture grain; (d) The pullout grain; For the (a) attrition wear grain and (b) part fracture grain, we consider the wear mechanism is frictional wear.
From the above grain forms counting results, we can see that the numbers of different grain forms are changing with the material removal in Fig. 16.
Fig. 16 The number of grains with different forms Fig. 17 The TWR vs. material removal Depending on the above grain forms, we measure the wear areas of each grain with different forms and draw the graph to reflect the relationship between material removal and TWR.

The average grain size was determined by SEM micrographs using the linear intercept technique by counting at least 500 grains and by multiplying the average linear intercepts length by 1,56.
The grain size distribution was measured based on an appropriate number of SEM images of each sample.
A large number of micrographs were obtained from each sample, allowing for the measurement of more than 150 individual grains.
Grain size distribution of samples heated to 1500ºC/2h and heated to 1050ºC/2h followed 1500ºC/2h.
The two-step sintering, which the alumina is heated at a higher temperature and then cooled, it was present more homogeneous sintered microstructure, coupled with a smaller mean grain size and narrower distribution in grain sizes.