Search results

On the other hand, the calculation domain must also contain a large number of grains in order to obtain statistically reliable results.
Similarly, it has been shown ‎[12] that for 3D grains the number of neighbours is on average close to 14.
To keep a sufficient number of grains in the domain, simulations were repeatedly interrupted to rescale the domain size, number of grains and grid size.
This technique effectively reduces the numerical cost of the 3D simulations while maintaining a statistically significant number of grains in the calculation domain.
Figure 4 -Variation of with number of grains in the simulation domain at the various simulation stages with different grid sizes, dx, for the grain growth case shown in Figure 2 a.

Finally, the mean grain size and the fraction of high angle grain boundaries were determined as a function of the number of cycles.
To characterize the formation of ultrafine grains, the evolution of both microstructure and texture has been analyzed by EBSD and the microhardness measured, as a function of the number of ARB cycles.
Fig. 3 illustrates the results obtained for the mean grain size and the fraction of HAGB as a function of the number of ARB cycles.
As the number of cycles increases, the average grain size decreases, reaching a value of 580 nm for n = 7, and the fraction of HAGB increases, reaching a saturated value after 5 cycles.
Fig. 3: Evolution of the mean grains size and the fraction of High Angle Grain Boundaries (HAGB) as a function of the number of ARB cycles n.

Figure 6 shows the stress-strain curve of the cemented coarse-grained soils and the coarse-grained soils.
Additional, the residual strength of the cemented coarse-grained soils are very close with that of the coarse-grained soils because the cemented coarse-grained soils material become similar to the coarse-grained soils material after all cement bonds broken.
Microscopic mechanism analysis Fig. 7 presents the cumulative number of cracks during the loading process.
The added number of cracks reached the maximum when the strain reached 1.5% ,which was the strain corresponding to the peak stress, and the number of cracks produced in the unite time reduced gradually until it reached a constant value.
Fig.9 shows the energy stored in the parallel-bond, it has the same evolution as the number of cracks.

Introduction Grain growth is commonly treated as a process of grain boundary migration not affected by triple junctions (TJ).
Grain growth kinetics is described by temporal alterations in the distribution and the mean grain size.
Grain growth kinetics in polycrystals with 0D = 68 lu and different m (see numbers).
If, however, second phase particles, pores or a low grain boundary mobility retard normal grain growth and lead eventually to the commencement of abnormal grain growth, the ratio increases with time steadily.
Time dependence of Dmax/DM in polycrystals with 0D = 68 lu and different m (see numbers).

Diffusion in an Ensemble of Intersecting Grain Boundaries A.N.
Grain boundary (GB) diffusion in an ensemble of three grain boundaries intersecting in the point of GB triple junction is described on the basis of quasi-steady Fisher’s model.
Two versions of the configuration of the ensemble are considered, namely, with different number of GBs adjacent to the surface covered with a diffuser source and with different angle between GB and surface.
It has been found that Zn diffuses along TJ lines in a coarse-grained aluminium with a columnar grain structure much faster than along GBs that form a TJ line [6, 7].
There are, however, a number of diffusion problems where a triple junction manifests itself as a singular point of space where the diffusion fluxes along GBs intersecting in TJ point merge or separate.

Therefore, the properties of polycrystalline materials strongly depend on the number, the structure as well as the character of the grain boundaries.
The fractions of grain boundaries of different types were determined in terms of the length fraction by dividing the number of pixels of a particular boundary with that of the entire grain boundaries [11].
And the maximum number of grains was obtained in the stage of complete recrystallization.
The absolute number of the low-Σ boundaries in the recrystallized specimens increased due to the number of grains multiplied.
Moreover, a large number of random boundaries and low-Σ boundaries were both generated, the number of random boundaries increased faster than the low-Σ boundaries during the recrystallization stage.

The elongation slightly decreases with the number of the ARB cycles, regardless of the stacking layer number.
knln 3 2 �� � � �� � � =� (1) Here, n is the number of ARB cycles, and k is the stacking number.
Optical observation revealed that it shows recrystallized microstructure with mean grain diameter of 37µm.
This is considered to be due to the difference in the grain size.
The elongation slightly decreases with the number of the ARB cycles, regardless of the stacking layer number

The initial grain was about 200µm.
(Phosphorus deoxidized copper) Number of Passes Strength (MPa) 10 20 30 40 50 60 Elnogation(%) Fig. 3 Tensile properties of oxygen free copper with respect to the number of ECAP passes.
Journal Title and Volume Number (to be inserted by the publisher) Results and discussion The microhardness as a function of number of ECAP pass was presented in Fig. 2.
Then, microhardness increases gradually up to 3 pass and saturated with further number of pass.
A large number of dislocations are observed within these bands.

Its mechanism is that Al4C3 particles can form a large number of dispersed sites for heterogeneous nucleation, and therefore enhance the nucleation rate.
In order to exactly describe the activation efficiency of grain-refiner in the melt, we define that the activation efficiency of the grain-refiner Al4C3 in the magnesium alloy melt, ρ, to be the ratio of the number of grains in unit volume after refinement to the number of particles which in size are bigger than or equal to the critical nucleation size.
(1) In the equation, λ is the number of grains in unit volume after the solidification of the melt and Ф is the number of particles which in size are equal to or bigger than the critical nucleation size.
(2) λ1 is the number of the grains in unit volume when adding Al4C3 grain refiner only. λ2 is the number of grains in unit volume when the Al4C3 grain refiner and the electromagnetic field acting simultaneously.
The number of Al4C3 particles of nucleation, Ф, is recorded as can be expressed as follows:

Area intensities of grain and subgrain boundaries, length intensities of triple grain and subgrain junctions, structural homogeneity and its thermal stability are strictly dependent on the number of passes.
It is generally believed that the grain structure improves with the number of passes but detailed structural studies are rather rare.
Let NA be the number of profiles per unit area of the test plane and NL the number of intercepts per unit length of the test line.
The effect of number of passes and subsequent annealing on the total intensities S, L [S] [µm-1] [L][µm-2] Number of passes 2 4 8 12 2 4 8 12 As pressed 1.1 1.6 2.1 1.6 1.1 1.9 3.4 1.8 After annealing and creep 0.28 0.28 0.29 0.35 0.09 0.11 0.10 0.13 Fig. 2 The effect of the number of passes on the fractions of boundary areas (left) and triple grain junction lengths (right) with misorientations in three intervals: subgrains 2 o ≤ ∆ < 10 o, intermediate boundaries 10 o ≤ ∆ < 15 o and grain boundaries ∆ ≥ 15 o.
Summary With increasing number of passes, the increase of boundary misorientations gradually proceeds; subgrains become grains but the total boundary area of grain and subgrain boundaries remains nearly constant.