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The grains were observed by means of light optical microscopy (LOM) and polarized light after Barker’s electro-etching and their mean grain size determined.
Grain fragmentation by lattice rotation and grain boundary serration were observed at high Zener-Hollomon parameter (Z) meaning high strain rate and low temperature combination.
The grain size is inversely proportional to the Z parameter.
The continuous rotation of the lattice followed by formation of high angle grain boundary (HAGB) is responsible of the grain refinement at temperatures larger or equal than 400°C.
The authors thank to AMAG GmbH for the provision of the material and to the Austrian Agency of Research founds FWF for supporting project number [P22238-N22].

Recently a number of researchers focused on the combination of ECAP with an appropriate post-ECAE heat treatment in order to regain the ductility [10-17].
The average grain size of the T4 condition is shown in Figure 5a is ~5 µm.
This suggests that the formation of a truly homogeneous ultrafine-grained microstructure has not been completed.
Nevertheless, ultrafine grains with an average size of ~ 300 nm are formed in some regions.
ECA-processing of the naturally aged condition above 220°C does not necessitate BP and yields a continuous decrease of strength with increasing extrusion numbers.

An influence of a real structure of a grain-oriented material on a stress-strain state was shown.
According to the radiograph data the degree of the grain-orientedness, i.e. a number of grains with a specific crystallographic orientation was determined.
The festoon height in FEM of the anisotropic grain-oriented by 70% sample is greater than in FEM of the grain-oriented by 40% sample.
a – isotropic; b – anisotropic; c – anisotropic grain-oriented by 40%; d – anisotropic grain-oriented by 70% a b c d Fig. 5.
Graphs of the force value changes on the punch in the drawing process of FEM parts. a – isotropic; b – anisotropic; c – anisotropic grain-oriented by 40%; d – anisotropic grain-oriented by 70% From the shown graphs it follows that the maximum stress in the deformation of the isotropic model is higher than those of the anisotropic, anisotropic grain-oriented by 40% and by 70% models.

On the basis of analyzing space relationship between scanning line and casting boundary, two conditions were gained, 1) the number of grids crossed by scanning line must be even number; 2) any two boundary grids crossed by scanning line must be not neighbored to each other.
For OGFM, any corner of mesh region can directly regarded as a grain to do filling operation.
In the paper, two algorithms to identify the grid nature are put forward, which are named Inner Grain Filling Method (IGFM) and Outer Grain Filling Method (OGFM).
When scanning line crosses through boundary grids, the existing cases can be summerized as: 1) scanning line encounters 1 boundary grid (fig.2 (1)); 2) scanning line crosses through 2 boundary grids (fig.2 (2)); 3) scanning line crosses through more than 3 boundary grids, and the grids number is odd number(fig.2 (3)); 4) scanning line crosses through more than 4 boundry grids(fig.2 (4)), and the grids number is even number; 5) scanning line crosses through a boundary line(fig.2 (5)); 6) scanning line crosses through double boundary grids(fig.2 (6)).
y x Fig.4 The grain filling for two isolated shapes The algorithm of OSGFM is shown in fig.3.

Grain growth occurred during the solid solution process.
This kind of precipitation consumes solute atoms in the alloy, making the subsequent aging process only a little number of solute atoms being able to precipitate the Age-hardening phase.
In the crystal within the matrix grains and at grain boundaries also exist a large number of spherical particles seeing as C area, the spherical particles were segregation due to the temperature reducing and deformation stress and other factors in the forging process, by XRD analysis verified that the precipitated phase are another kind of intermetallic compounds, Mg5(Gd, Y,).
While the matrix grain size hasn’t grown up too much, there is well coordinating effect between matrix grains.
Grain Refining Mechanismin Mg-9Gd-4Y Alloys by Zirconium [J].

A large number of subsequent efforts on ceramics as well as single-crystal samples were made to explain the universal dielectric properties of CCTO based on respective experimental results, and revealed additional features, such as dipolar relaxation, relaxor behavior and strong non-linearity [2-5].
The polygonal grains and an unobvious bimodal distribution of grain size have been observed.
Ceramics with small grains has higher grain boundary concentration, corresponding to higher compression on grains, than that with large grains[4, 16].
Inset is the Arrhenius plots for the conductivities of grain and grain boundary.
Complex impedance analysis has been used to distinguish the resistance between grains and grain boundaries.

Therefore the grain orientation spread is not independent on the grain size.
The minimal number of points, which are required to decide whether a given group of points should be considered as "grain" (the Minimum Grain Size), can be specified by the user along with the Grain Tolerance Angle.
Fig. 3 shows the grain misorientation and the grain orientation spread as a function of creep time.
This is the stage of the process when the strains within the grains have the maximum value, as the grain orientation spread and the grain average misorientation values show it.
In this period the average subgrain size is the smallest, i.e. there is the maximum number of small angle boundaries, therefore the strength of the material is the highest.

The number of the cycle times was pre-set according to the conditions in experiments, the experiment would be interrupted if it reached the number, and then the middle surface short fatigue crack on notches would be observed and recorded, after that the experiment continued.
At the early stage of short cracks’ fatigue life, initiation is the main forms of fatigue damage (Figs.3 (b)-(d)), and the increasing in numbers of short crack instead of in length by the influence of the grain or phase boundary barrier.
The crack growth data are showed in Fig.5 and Fig.6, where x-axis is presented in two different life forms, one is the numbers of cycles; the other is the percentage of life.
The fatigue crack length at the plateau regions was 20~100mm, which equaled 1~5 grain boundary length.
The influence of barriers will not disappear until the crack length increases to 1~5 grain boundary length

When the recrystallization is complete (), further grain growth takes place to reduce the grain boundary area per unit volume.
(2) where is DRX fraction, is strain for 50% recrystallization, is initial grain size, is recrystallization grain size, is growth grain size, and is average grain size.
The total number of element and node are 28116 and 6408, respectively.
Distribution of average grain size.
The grain size in the region Ⅳ is the finest compared with that of other regions and the average grain size is about 30 (μm).

With world-wide strict legislation for reduction or removal of lead from industrial waste, development of a large number of lead-free alternative solder materials had been intensively examined.
However, application of this Pb-Sn conventional solder alloy have prompted numbers of problems associated to the restrain of lead-containing substances[3].
The transport processes controlled by Al diffusion along grain boundaries as the dispersed Cr and Al nanoparticles and a great number of grain boundaries promote rapid selective oxidation for Al after oxidation, subsequent to a continuous fine-grained oxide formation.
Striking improvement in the film microstructure, in terms of the compactness, uniformity and refinement of grains was found with the addition of these additives.
(c) Gelatin with thiourea and OPPE:- smoother, more uniform, compact and finer grain, with grain size of about 3–4µm films was observed. [21] Summary Electrodeposition can be used to synthesize a large number of nanocrystalline metals, alloys, and composite materials.