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For example: orientations, dislocation densities, grain sizes etc.
The grain structure corresponds to material points within the box marked O.
These nuclei are then allowed to grow and erase the old grain boundaries.
(b) Proportion of new CA cells to the total number of cells in a finite element.
Fig. 4b shows the proportion of new CA cells that are occupied by the recrystallised nuclei to the total number of CA cells associated with an integration point.

Introduction Grain refinement is an important process to increase the strength of metallic materials.
However, it is generally difficult to achieve combined effects of both grain refinement and fine dispersion of precipitates.
Provided that such a supersaturation is achieved in an ultrafine-grained alloy, another important task is to make fine precipitation within the fine grains by subsequent aging while keeping the grain size small.
The hardness increase is faster with increasing number of the revolution as reported in other metallic materials [10-12].
(3) Simultaneous hardening due to aging and grain refinement was attained in the 2091 alloy.

Our previous TEM observation revealed that a large number of dislocations were accumulated on slip planes in the Ni3Al elongated pancakes, while they were rearranged into a cell structure in the Ni matrix [6].
In detail, there are a small number of regions having a Goss orientation (dark grey), which Goss component was not detected by the X-ray texture measurement.
They can be assumed to disappear when grain growth proceeds, because their size is smaller than the other grains.
The possibility for this encounter increases as the number of the 40˚<111> rotated Goss grains increases with the progress of the recrystallization.
This may cause the diminishment of the Goss grains during the grain growth.

The small equiaxed grains corresponds recrystallized grains.
The mentioned parameters expressed deformation path de according to the relation given in [6], where the proportion of the number of torsion cycles resulting from an increment in absolute strain over time affects the compression force and structural effects.
To form a submicron grain structure with the COT method, a high density of high angle grain boundaries must be generated with a spacing approaching the subgrain size.
Such behavior is typical for a coarse - grained material.
Hence, strong dislocation activity accompanies grain fragmentation.

The average grain size of AZ91D alloy is about 40μm.
(1) Where σr is fatigue strength; k is the numbers of coupled reverse results; m is the stress level series; n is the efficient specimen numbers which can be coupled; σj is the fatigue strength at No. j grade stress level; σi is the stress value at No. i grade stress level; υi is the specimen numbers at No. i grade stress level.
The fatigue crack is propagated along grain boundary as well as transgranular form.
The facet sizes are nearly the same as, or smaller than, the average grain size.
Fatigue cracks of AZ91D alloy initiate principally at inclusions of alloy subsurface, and propagate along the grain boundary.

Ultrafine-grained (UFG) structure with grain size 1-2 μm and coarse grain (CG) 20-30 μm were obtained by thermal annealing at a temperature below the recrystallization temperature [12].
Microcracks propagate mainly along grain boundaries and have uneven branching.
The numbering of stages is retained by the previously introduced Ivanova V.S. and Terentyev V.F. classification [4, 5] regardless of their availability.
Their number is not significant, and the dimensions do not exceed 3 μm.
a) b) Figure 5 – Microstructure of the submicro-crystalline sample They are poorly noticeable with an increase in x 1000, obtained with the help of an optical microscope, but their number is much larger than the number of twins detected for the UFG structure.

It is good for the future production of grain refinement we need.
The grain sizes of this two group samples are shown in Figure 1.
A B C D E F 30 40 50 60 70 80 90 100 Grain Size um Specimen Fig.1 Sample average grain radius Figure 1 shows the grain sizes of the first group samples are greater than that the second group samples.
Refinement effect with atomic number ratio of is stronger than that with atomic number ratio of .
When the atomic number ratio is , TiB2 and ZrB2 generate.

Introduction Fabrication of sheets out of coarse-grained Al alloys with equiaxed grains and isotropic mechanical properties is a complicated task due to both the texture formation and elongation of grains during rolling.
In this case one can expect the development of grain-boundary sliding retaining equiaxed grains.
ECAP was conducted with the number of passes n=10 at a temperature of 370°С and a traverse speed of ∼ 6 mm/s.
The mean grain size was calculated according to dark-field images.
Results The initial billets out of 1421 alloy had elongated grains up to 70 µm with 20 µm in cross section and with the S-phase particles (Al2LiMg) [6,7] with the mean grain size 5 µm and a volume fraction ≈ 6 % located mainly along grain boundaries.

The relatively low decrease in microhardness during HTE may be explained by grain growth which is retarded by Al2O3 nano-sized particles precipitated at the grain boundaries.
The grain size was calculated using equation 1.
The grain size, D, of compacts as a function of milling time.
This dislocation network activates the formation of significantly increased number of subgrains which may become the nucleation sites of newly formed recrystallized grains.
Nano-sized Al2O3 particles form a great number of interfaces considered as a possible source of additional electron scatter, which is a significant factor in reducing conductivity [3].

The different colors are assigned to different grain orientations.
The nearly identical color of two grains means that the misorientation between these two grains is small.
The average grain size of the HPT AA5182 alloy is about 79 nm.
(a) Area fraction distribution of the grain size; (b) Number fraction distribution of the misorientation angle.
Meanwhile, with the reduction of grain sizes, dislocations are no longer sustained within grain and, once generated, rapidly diffuse to the GB [13,24].