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The effects of number of grains on simulation reproducibility depending on crystal orientation are investigated by the obtained numerical results.
Shape of grains is almost isotropic and the deformation twin can be observed in some grains.
The mean size of grains is about 3.21 mm when the grain boundary is defined as a boundary whose misorientation angle is larger than 15°.
The unit-cell model is composed of 151 grains whose mean grain size is 3.21 mm.
Numerical simulation with number of grains of 77 had variations in contours of the plastic work.

The tensile strength, compressive strength and the elongation to failure of the fine-grained AZ31 are enhanced due to the reduction of grain size.
Reduction of the mean grain size is also expected to promote super-plastic deformation at higher strain rates and/or lower temperature than those conventionally used for large grain size materials.
The number of ECAP passes was six.
The structure is an equaled grains with a grain size of about 120µm.The sample subjected to six passes has a homogeneous, fine-grained microstructure with a grain size of about 8µm, as it can be seen in Fig. 1b.
A fine-grained Mg alloy AZ31 was obtained by ECAP.

Simulation model Grain growth model.
Thus a relation can be obtained between grain size (Lmax) at the highest sintering pressure, σmax, and grain size (Lσ) at an arbitrary sintering pressure σ: (7) where kP is pressure factor which reflects the possibility of grain growth.
Lattice sites having the identical Q number are considered as a grain, and a grain boundary segment is defined to lie between sites of different Q number.
In order to study the effect of sintering pressure on microstructure evolution, the pressure factor, kp, is coupled into MC Potts model, the probability of switching the orientation number at a lattice site is determined by evaluating the energy change ΔE [8] during reorientation.
It can be found that the mean grain size of matrix phase increases with an increment in sintering pressure in the same simulation time, and the number of nano-particles entrapped into matrix grains increases accordingly, indicating that higher sintering pressure is beneficial to grain growth and the formation of intragranular-type microstructure.

The size of the ferrite grains is by an order of magnitude less than the original grains size.
Closer to the disk axis the number of defects increases sharply.
The maximum number of twins in large ferrite grains which includes the twins belonging to different systems is more than one hundred.
The number of twins grows on getting close to the centre of the plate under examination.
A great number of cracks is seen along the localized plastic flow bands (Fig. 8 a).

A gradient nature of changes in the number of stress concentrators when moving away from the failure surface was defined.
The scalar density of dislocations in grains without a band structure was about 3.3x1010 cm -2 .
However, broken sub-boundaries are often observed in grains with a chaotic dislocation structure.
The scalar density of dislocations in grains without a band structure was about 3.6x1010 cm -2 .
The scalar density of dislocations in grains without a band structure was about 3.1x1010 cm -2 .

Enhancing nucleation in the initial stages of solidification can increase the latter number of α-Al, where this can be achieved through using high cooling rates or adding grain refiners like TiB2.
Addition of Mn and Al-5Ti-1B grain refiner will enhance heterogeneous nucleation in the Al melt, thus this will aid in the prompt growth of α-Al grains.
The average grain size is shown in Table 3, for alloys I and II.
This is explained through an increase in the latter number of grains, as both Mn and TiB2 cause for there to be an increase in latent heat of extraction.
When there is a small grain boundary area, the liquid film around the grain envelopes will be significantly smaller and thinner [2,7].

Fig. 5a-b shows the histograms of the internal stresses σ in grains with simple and complex grain bending for the deformation degree ε = 14 %.
The distribution analysis showed that both at simple and complex grain bending of a grain one sees the inhomogeneous polycrystal grain deformation.
Consequently, the number of more stressed sample sections (σ > 2 GPa) is insignificant.
It should be also pointed out that the total area of the second and the third mode for a grain with complex bend is greater than for a grain with simple bending, i.e. the number of sample sections with the internal stress increasing 2 GPa is greater at complex grain bending than in grains with simple bending.
This is explained by considerable relaxation of the internal stresses in steel caused by appearance at ε > 20% of a great number of microtwin packages in the deformed material.

High Temperature Deformation of Cast ZW11 Magnesium Alloy with Very Large Grain Size K.P.
However, the resultant alloy developed a very coarse grained microstructure with a grain size in the range of 2,600 to 4,000 μm (2.6-4.0 mm).
The numbers associated with the contours represent efficiency of power dissipation in percent and the shaded areas represent flow instability regimes.
The numbers for the contours are efficiencies of power dissipation and the shaded areas are flow instability regimes.
The developed microstructures reveal complete recrystallization and the grain sizes are in the range of 30-60 μm, with finer grains corresponding to higher strain rates of deformation.

Superplastic behavior and cavitation were investigated for WC-15 mass % Co cemented carbides with the WC grain sizes of 0.7 µm (A) and 5.2 µm (B), WC-10 mass % Co cemented carbide with the WC grain size of 1.5 µm (C) and WC-5 mass % Co cemented carbides with the WC grain sizes of 0.5 µm (D) and 2.5 µm (E) by tensile tests at 1473 K.
The WC grain size, dWC, and the mean free path of Co phase, λCo, are given by [9] s L WC N N d ⋅= π 4 (1) L Co N f− = 1 λ (2) where NL is the number of the carbides intercepted per unit length, Ns is the number of the carbides included per unit square and f is the volume fraction of carbide.
Values of the WC grain size, the free path of Co phase and the WC contiguity for the cemented carbides.
WC grain size, µm Mean free path of Co phase, nm WC contiguity Fine-grained WC-15 mass. % Co cemented carbide (A) 0.7 55.7 0.51 Coarse-grained WC-15 mass. % Co cemented carbide (B) 5.2 154.4 0.31 Medium-grained WC-10 mass. % Co cemented carbide (C) 1.5 533.4 0.27 Fine-grained WC-5 mass. % Co cemented carbide (D) 0.5 23.4 0.56 Coarse-grained WC-5 mass. % Co cemented carbide (E) 2.5 109.8 0.49 Results and Discussion SEM photograph of A annealed at 1473 K for 1.8 ks are shown in Fig. 1, where the specimens were polished mechanically and then etched with Murakami reagent.
The WC contiguity, which is one of parameters representing the number of the WC grain in direct contact with the WC grain without the Co phase, is given by [10] WCWC CoWC WCWC WC NN N C / / / 2 2 − = (3) where CWC is the WC contiguity, NWC/WC is the number of interfaces between WC grains intercepted per unit length and NWC/Co is the number of interfaces between WC grains and Co phase intercepted per unit length.

The results are shown in Figs. 6a-6d, in which the number fraction is calculated by dividing the number of grains of certain sizes by the total number of grains counted.
This deformation-induced grain growth is associated with grain boundary migration, grain rotation, and grain coalescence, which will be discussed later in more detail.
The deformation amount is expressed in terms of true strain, and the number fraction is calculated by dividing the number of grains of certain sizes by the total number of grains counted.
The terms 'transverse' and 'axial' denote the direction perpendicular to and parallel to the loading direction, respectively. 0 20406080100 0.00 0.05 0.10 0.15 0.20 0.25 0.30 Number fraction Grain size (nm) 0% Transverse 0 20406080100 0.00 0.05 0.10 0.15 0.20 0.25 0.30 Number fraction Grain size (nm) 0% Axial 0 20406080100 0.00 0.05 0.10 0.15 Number fraction Grain Size (nm) 40% Transverse 0 20406080100 0.00 0.05 0.10 0.15 Number fraction Grain Size (nm) 40% Axial 0 40 80 120 160 200 0.00 0.05 0.10 Number fraction Grain size (nm) 140% Transverse 0 20406080100 0.00 0.05 0.10 0.15 0.20 0.25 Number fraction Grain size (nm) 140% Axial (a) (b) (c) (d) (e) (f) In a uniaxial tensile test of nc-Ni, the plastic deformation is typically less than 2% [7, 15, 28].
Molecular dynamics simulations of uniaxial deformation of nanocrystalline metals revealed that grain boundary sliding takes place mainly via a large number of small local sliding events of atomic clusters that comprises a few or at most a few tens of GB atoms [33, 35, 36].