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The X-ray method to determine the dislocation density has a number of advantages in comparison with the direct observation of dislocations by means of TEM: high statistical significance of obtained results, separate observation of effects from dislocations with different Burgers vectors, selective possibility to determine the dislocation density in grains with any orientation of interest, possibility to construct the distribution of dislocation density depending on the grain orientation.
In particular, since each α-grain contains only one axis <0001>, one-to-one correspondence exists between orientations of these grains in PF(0001) and orientations of the Burgers vector for their cdislocations.
When the X-ray study is extended to grains with different orientations, the method of Generalized Pole Figures (GPF) proves to be most appropriate, where GPF is the distribution of diffraction or substructure parameters of reflecting grains in the stereographic projection of the sample [4].
In particular, grains with dislocation densities ρc and ρa from 1×1014 up to 1×1015 m-2 account for volume fractions of 33% and 40% respectively, whereas grains with dislocation densities ρc and ρa above 1×10 16 m-2 - for volume fractions of 11% and ~1%.
Grains with basal axes at T-direction deform predominantly due to tangential compression by the decrease of the tube diameter, whereas grains with basal axes at R-direction - due to radial compression by thinning of the tube wall.

It is imposed by the reduced rotational symmetry for this direction which favours the activation of a low number of glide systems.
This is produced by several individual large grains which are displaced in angular position by the values corresponding to the instrumental resolution rather than by a fine grained micro domain structure which would be noticed by smoothly broadened rocking profiles.
Back scattering Laue pictures with spot sizes of 0.5 mm confirm the existence of macroscopic grains and such grain boundaries deferred of the crystal surface can even be from an inspection by Fig. 1.
It has no separated grains with constant orientation, but a drift of orientation outside the facetted region.
Summary Crystals grown in the [01-15] direction show a different macro and micro grain structure than [0001] crystals.

The combination of high strength with a sufficiently high electrical conductivity in samples subjected to DL-LNT is explained by a formed mixed microstructure, containing elongated grains with a large number of dislocations, areas with nanotwins, a volume fraction of nanotwins in which was 20%, and particles of the secondary phase.
The average size of the elongated grains was d»1600 nm.
The grains contained dislocations of high density.
They consist of a large number of dislocations.
Valiev, The determination of the grain boundary width of ultrafine grained copper and nickel from electrical resistivity measurements, Phys.

The analysis of rolling texture formation is done for two types of lattice rotation in function of grain-matrix interaction parameter used in a deformation model.
It is based on the assumption that a resultant rigid body rotation of each grain and of the sample are the same, at least statistically.
Crystal lattice rotation A glide δg on the slip system (n, m) produces a rigid body rotation (plastic rotation) of grain: .
The rolling textures were predicted for the following parameters: N=5000 (number of grains), G=46 GPa and 50% rolling reduction.
Another important parameter is the magnitude of grain-matrix interaction (a).

The substrate show fine equiaxed grain, and the grain size is about 4 µm, as shown in Fig.1(d).
It is evident that grain sizes are different in three zones.
It is easy to understand that the closer to surface of Mg alloy, the absorb energy of grain should be higher, which promotes grain growth.
It is well known that microstructure in NZ for FSW welds generally presents fine equiaxed grain [13], and its grain size is less than that of BM and HAZ.
No other crystalline phase peaks can be observed, that indicates a great number of metallurgical reactions between Al coating and Mg alloy don’t occur on the interface.

It is found that surface damages increased with the rogue grain size and concentration, and the large grains present even at a very low concentration can degrade the surface quality in the loose abrasive processing[1].
The force on the large particle equals the one on other abrasive grain.
The quantity of the large particle is described by concentration, i.e. the number of large particles in 1mm2 area on the SAFT surface, and the number is counted under stereomicroscope.
When it comes the concentration degree V, it is too many to count, the number of the large particle is not listed in Table 3.
When the number of the large particle in the machining area exceeds the critical value, the effectiveness of 'trap' effect goes down.

- Interactions between precipitation and recrystallisation and their effects on grain refinement
It is also observed that, in spite of the big difference in the prior austenite grain size, the grain sizes start to converge after several passes.
Evolution of grain size after reheating at 1400°C and 1200°C, prior austenite grain size as 806 and 129 µm, respectively.
During multi-pass deformation process, grain refinement takes place as well as ferrite formation from austenite.
The deformation resistance calculation has been carried for a number of steels, Fig. 8-10, with alloy compositions and experimental details given in Refs. 24 and 25.

With increasing negative voltage, the surface became thinner with a lesser number of nuclei.
The grain structure varied from the continuous film at 0 kV to the channel at -1 kV, and further to the islands (mounds) at -5 kV.
Increasing applied negative voltage makes the surface smoother with lesser number of particles.
With increasing negative voltage, the surface became thinner with a lesser number of nuclei.
The grain structure varied from the continuous film at 0 kV to the channel at -1 kV, and further to the islands (mounds) at -5 kV.

Subsequently, a number of efforts were made to investigate the effects of magnetic annealing on the development of recrystallization and recrystallization texture in ferromagnetic materials [2-6].
They showed that the nucleation of {111} oriented crystals occurs in deformation banded γ grains, since α deformed grains contain only small lattice curvatures, and in-grain nucleation is rare.
When the holding time is 10min, the retained deformation bands are much bigger in the T/℃ 650℃ B=12T B=0T 0min 10min 30min 120min 650℃ field annealed specimen than in the non-field annealed specimen, and the number of recrystallization grains in the former is also much less than the latter, even though there are some abnormal growth grains in the field annealed sample (Fig.2 (c) and Fig.2 (d)).
When the holding time was increased to 120min, the process of recrystallization finished completely, but the recrystallization grains were not equiaxial (see Fig.4) because the annealing temperature (650°C) was not sufficiently high. 25μm 25μm 25μm 25μm 100μm 100μm Fig.3 The number percentage of recrystallization grains obtained at 650°C for different holding time with and without magnetic field.
Furthermore, the domain walls can also act as a barrier to grain boundary migration [16].

Abrasive grain in the furrow surface of the plastic material, not once, can produce chip, chip formation process is more complex.
The extension of metal material has a certain limit, one or more impact in the grinding grain, when the deformation exceeds material allowed an extension of the limit, cracks will occur in the material surface, when it has again been grinding grain effect form chip was broken down.
Therefore, influence the factors of cutting mechanism of the plastic material is mainly abrasive impact velocity, point grinding grain number, relatively than the hardness and mechanical properties of target material.Abrasive impact velocity depends on factors such as water pressure, nozzle diameter, reflects the impact kinetic energy of the abrasive particle.
The grain number of abrasive grinding are connected with unit time supply, factors such as feed rate.this is a characteristics quantity that the abrasive jet cutting different one made of erosion wear.
As a result, the speed of the grinding grain is not the higher the better, but there is a optimal value.