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Results shows, the stress-induced anisotropy of coarse-grained soil occurs under the interaction of internal irregular microscopic structure and external non-isotropic stress.
Introduction Anisotropy is one of the basic mechanical properties of the soil, especially for non-continuous material such coarse-grained soil.
There have been many achievements about coarse-grained soil anisotropy.
For sample D, since it experienced initial non-isotropic stress state, the number of long axis orientation in the interval of (-900,-600) and (600,900) obviously decreases，the number of long axis orientation in the interval of (-600,-300) and (300,600) also decrease，but the number of long axis orientation in the interval of (00,300) and (-300,00) obviously increases, clump long axis orientation changes obviously.
(3) stress-induced anisotropy of coarse-grained soil will occur under the interaction of internal irregular microscopic structure and external non-isotropic stress.

Self-Diffusion Parameters of Grain Boundaries and Triple Junctions in Nanocrystalline Materials A.G.
Suggested methods describe the process of self-diffusion along grain boundaries and triple junctions in polycrystals without using geometric models of the grain boundaries structure.
Introduction Diffusion along grain boundaries (GB) in polycrystals is a process of atoms displacements with energy barriers overcoming in the grain boundary area, which forms the basis of the mechanisms of grain boundary migration, grain growth, the allocation of secondary phases at grain boundaries, Coble creep and other diffusion-controlled processes in polycrystals.
Significantly greater rate of diffusion along grain boundaries in comparison with the diffusion in the bulk of the crystal grains was found, the classification of regimes of grain boundary diffusion and grain boundary diffusion processes was studied in many polycrystals.
Following which effects on the model samples were switched off and the simulation was conducted by NVE (constant number of particles, volume and total energy) MD scheme.

Introduction Adding grain refiner is an effective and practical way to refine Al alloy grains[1-3].
As an efficient grain refiner for Al and its alloys, Al-Ti-C grain refiner has a low tendency of "poisoning", and its production is pollution-free.
The minimum grain size that can be achieved is 100 μm.
The effective nucleation number of α-Al is also increased under the action of high intensity ultrasonic, which making the fading less likely to occur.
Greer, Grain refinement of Al alloys: Mechanisms determining as-cast grain size in directional solidification, J.

With increasing the number of ARB cycles, Vickers hardness of the specimens increased and reached to a constant value.
It is obviously demonstrated that the grain subdivision[9] takes place with increasing the number of ARB cycles.
With increasing number of ARB cycles, density of high-angle grain boundary increases.
Number of cycles Vickers hardness, HV Fig.3 Change in Vickers hardness as a function of number of ARB cycles of the Al-0.2wt%Zr specimen.
Number of cycles 0 1 2 3 4 5 6 7 8 9 10 11 0 50 100 Fraction of HAGBs, fHAGBs(%) Fig.5 Fraction of high-angle grain boundaries (fHAGBs) as a function of number of ARB cycles in the Al-0.2wt%Zr. 5µm 5µm 50µm 5µm θ ≧ 15° 15°＞ θ ≧ 2° (a) (b) (c) (d) RD ND Figure 7 shows the grain boundary maps obtained by EBSD measurement of the ARB specimens aged for 360s at 623K or 723K, respectively.

However, as the grain size was reduced, fewer of these aligned microstructural features were formed, and at the smallest grain sizes, there was little evidence of significant substructure within the deformed grains.
Different grain sizes then were obtained by annealing the extruded bars, to coarsen the microstructures by grain growth.
In the 3µm grained material, micrographs showed no evidence of aligned substructures within the grains.
The low angle boundaries are considered in two misorientation groups, 0-3 o and 5-10 o and figure 3 presents data from samples of 60µm and 3µm grain size, where the number of boundaries analysed in each histogram is typically 5000-10000.
Low angle boundary alignment to the rolling plane in samples deformed to a strain of 0.7. a) 60µm grained material, 0-3o boundaries b) 60µm grained material, 5-10o boundaries, c) 3µm grained material, 0-3o boundaries and d) 3µm grained material, 5-10o boundaries.

Anomalous Effect of Strain Rate on the Tensile Elongation of Coarse-grained Pure Iron with Grain Boundary Micro-voids Xin-Ming CAO1, Qi-Qiang DUAN3, Xiao-Wu LI1,2,a 1 Institute of Materials Physics and Chemistry, College of Sciences, P.O.
Experimental results Figure 1 shows the microstructures of the raw coarse-grained CP iron.
From Fig. 1(a), the average grain size was measured to be about 200 mm.
In addition, as representatively shown in a magnified SEM image of Fig. 1(b), a number of micro-voids were found to pre-exist at GBs, and most of the micro-voids are in the size of several microns.
Fig. 1 Initial microstructures of the raw coarse-grained CP iron.

At the same time, significant grain refinement down to ~100 nm in diameter takes place in aluminium phase.
On the other hand, there are a number of possibilities to improve the mechanical properties of Al-Si alloys by micro-alloying and heat treatment [2-3].
After HE the grain size decrease to 119 nm and 109 nm, respectively.
The processing leads to significant grain refinement and particle redistribution.
Acknowledgment This work was supported by the Polish Ministry for Science and Higher Education (grant number 3T08A 06430).

Grain boundary sliding.
Figure 1.h shows the grain boundary offsets that occur in grains orientated at an angle offset to the tensile direction, with the early start of accommodation by surface grain separation or grain emergence.
This was observed across a number of grids, as well as at various locations on the surface that had not been FIB milled.
Again, this was exhibited across a number of grids, and in surface areas not FIB milled.
The number and size of these defects were believed to vary with strain-rate.

Modeling Grain Boundary Mobility during Dynamic Recrystallization of Metallic Alloys F.
Introduction Grain boundary migration plays an important role in dynamic recrystallization because it is one of the main parameters controlling the final grain size after hot working of a material.
(The other solution, ρ = 0, corresponds to the nucleation of a new grain.)
The grain boundary mobility in particle and solute-containing metals undergoing DDRX is therefore obtained by combining Eqs. 7 (assuming here that its validity range extends up to M = 0) and 8a, viz., ( ) ( ) z z 0 m s 1 k M M 1 C C − ρ ρ = + α (9) Particle Size and Solute Concentration Dependence of Grain Boundary Mobility Assuming spherical particles, the Zener pressure is given by [4]: ( ) 2zP 2 n d= π γ (10) in which γ is the surface energy of the precipitates, n is the number of precipitates per unit volume, and d denotes their diameter.
In the cross-hatched area, the grain boundary mobility is zero.

Aydiner et al. determined the grain-resolved stress tensors for several grains in a coarse-grained (100 μm) Mg alloy sample with a cross-sectional diameter of 1.2 mm, that was subjected to plastic deformation [10].
Such samples tend to give rise to overlap of diffraction spots from a large number of grains on the area detector, which is a serious problem with the 3DXRD technique.
To overcome this problem, we previously proposed a scanning 3DXRD technique [14], in which a two-dimensionally focused microbeam is used to reduce the number of diffraction spots in the recorded pattern.
Because only the grain at point Q is always illuminated by the incoming beam, it can be assumed that the ratio of the number N of recorded diffraction spots to the theoretical number M of diffraction spots from a single crystal with the same orientation is larger for this grain than for all other grains.
The scanning 3DXRD method is useful for polycrystalline samples with a large number of grains in a given cross section.