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The number of dynamic recrystallization grains is less at lower temperature and higher strain rate than higher temperature and lower strain rate.
The initial grain size was about 80μm (Fig.1).
Generally, the number of dynamic recrystallization grains is less at lower temperature and higher strain rate than that at higher temperature and lower strain rate.
Fig. 4 Dislocation structures of the deformed material at T=623K and =0.01s−1 (a) in the vicinity of initial grain boundaries (b) inside of the subgrains (c) inside of the twins A number of twins are visible in compressive specimens.
(2) DRX grains gradually occur in the vicinity of initial grain boundaries.

However, arbitrary number of crystal orientation can be described by only two order parameters.
The KWC model also allows for the grains to rotate.
Hslam et al., in their Molecular-dynamics (MD) studies [21-23], have indicated that both grain rotation and grain boundary migration occur during grain growth in nanocrystalline material.
In the case of grain of region A, we can see many high angle grain boundaries and high dislocation density distributions.
On the other hand, in grain B, the high angle grain boundaries and the high dislocation density are observed only around the original grain boundaries.

Bulk ultrafine-grained Nickel consolidated from nanopowders J.
HIP), thus preventing grain growth.
With increasing strain, the number of loops increases and the stress field of these loops hinders the emission of new dislocations from the grain boundaries.
As the dislocation emission from the grain boundaries is hindered in the SPS-processed specimen, the further plastic deformation is most probably mediated rather by grain rotation or grain boundary-related mechanisms such as sliding and/or decohesion.
The further deformation of the SPS-processed samples is probably mediated mainly by grain rotation and/or grain boundary-related mechanisms.

D=i=1N4AπN (1) Fs=Ni=1NP24Aπ (2) where D, Fs, A, N and P are the average equivalent grain diameter, shape factor, area, number of grains and perimeter of the primary α-Al grains, respectively.
After liquid 6061 aluminum alloy flowed through the serpentine channel, the semi-solid slurry contained a large number of spherical primary α-Al grains.
When injected into the die mould, the slurry was chilled by the die mould, and so the residual liquid immediately solidified, resulting in a large number of secondary solidified α2-Al grains.
There are a large number of tiny dimples at the edge of the tensile specimen in Fig. 5(d).
Due to the chilling effect of the mould wall, the residual liquid rapidly solidified, and a large number of fine grains were distributed on the edge, as shown in Fig. 6(f).

Most models that simulate or calculate the microstructural evolution at the particle scale focus on a very small number of particles.
E = 1 2 1"# qi,qj( )( )j=1 n $i=1 N $ (1) where i is each site, N is the total number of sites in the system, j is each neighbor of site i, n is the total number of neighbors of each site, qi is the state of the grain or pore at site i and qj is the state of the nearest neighbor at site j and δ is the Kronecker delta with δ(qi = qj) = 1 and δ(qi ≠qj) = 0.
Time in a kMC model is measured in units of Monte Carlo step; 1MCS corresponds to N attempted changes where N is the total number of sites in the system.
Images obtained from the numbered points indicated will be used for model validation.
Sintering was simulated by attempting Ng (number of grainsite) grain growth step, Np (number of poresite) pore migration step, and vacancy annihilation with a frequency given by Eq. 3.

The number and the size of the second phase particles on the grain boundaries did not depend on the copper content.
The size of the second phase particles on the grain boundaries was less than a 0.5µm diameter, and the number of second phase particles on the grain boundaries was less than 100 per mm.
This result suggests that the total length of the second phase particles on the grain boundaries per the length of the grain boundaries was less than 5%.
The number and the size of second phase particles on the grain boundaries did not depend on the solution heat treatment time.
The size of the second phase particles on the grain boundaries was less than 0.5µm, and the number of second phase particles on the grain boundaries was less than 100 per mm.

An UFG microstructure with a mean size of secondary grains of about 0.3 μm was processed by a rotary swaging.
In the cross section, grains of primary phase were curved and took an oval shape with a mean size of about 2 μm.
TEM studies showed the formation of subgrains and increased dislocation density inside primary α-grains.
Acknowledgements The reported study was funded by RFBR, project number 20-38-70105\20.
Zhu, Producing bulk ultrafine-grained materials by severe plastic deformation: ten years later.

The influence of alloying elements on grain boundary and bulk cohesion in aluminum alloys: ab initio study.
There exist a number of ab initio studies of the impurity effect on the GB’s energy characteristics in aluminum [11,12,13], where the special GB was studied and the effect of Ga and Ca on the set of GB’s properties was estimated.
Rybin: Grain boundaries in metals (Metallurgy, Moscow, 1980)
Straumal: Grain boundaries phase transitions (Nauka , Moscow, 2003)
Shvindlerman: Thermodynamics and Kinetics of Grain Boundaries in Metals (Metallurgy , Moscow, 1986)

.:81-424-75-0650 e-mail: wmfjindo@din.or.jp Atomistic Simulation Study of Dislocations and Grain Boundaries in Nanoscale Semiconductors K.
In terms of X and r the particle number Ne and energy functional W are given as Ne = tr[3X SX - 2 X SX SX )S], ( ) [ ]HXSXSXXSXtr 23 =W
The major difference in the grain boundary properties between the nanoscale and bulk crystals is in the significantly smaller excess energy of the grain boundary in the former nanoscale crystals.
In Fig.3c, one can see no gap states appear for S=9(221) tilt grain boundary in Si-nanowires.
This is due to the fact that the effects of compressed and stretched bonds in the core region of the grain boundary almost cancel and effective coordination number remains around the value of 4.

Non-homogeneous melting then takes place at these places, and the inner crystal grains melt more easily in liquid surroundings presented by the melting grain boundaries.
The total number of carbon atoms in the polycrystalline system is 156,226, and the number of the atoms in the grain boundaries is 25,464 which is 16.3% of the total number.
Atoms with the most populous coordination number 4, that is the atoms in a perfect diamond lattice, are coloured with gray; similarly, atoms with the second most populous coordination number 3, in grain boundary, are coloured with forestgreen.
Other atoms with the coordination number 1, 2 and 5, also in grain boundary, are coloured with turquoise, burlywood and red, respectively.
However, some parts of the grain boundaries were melted as some atoms in this area have fewer numbers of coordinations than in the initial stage (the amount of the atoms coloured with turquoise and burlywood increased).