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Surface defect grains formed on the surface of turbine blades: a) stray grain, b) equiax grain, c) freckle chain grain, d) low angle grain, e) surface pit grain, and f) recrystallized grain.
As already shown in our previous papers [9], each cross section of the surface defect grains showed an intermediate layer composed of elongated γ′ phase with a number of tiny Re-rich particles through the whole cross section.
Most of all, another cross section along the layer (Fig. 2c) clear shows that there are a number of tiny Re-rich particles in the layer.
A high magnification image (Fig. 3b) clearly shows that there are a number of Re-rich particles.
The cross section showed an intermediate layer composed of elongated γ′ phase with a number of tiny Re-rich particles regardless of the formation mechanism of each defect grain, which means that if there is any boundary region in a turbine blade, the layer and secondary phases can be found.

The scatter effect of grain behavior can be attributed to different grain sizes, shape and orientations which can be employed into each grain as a single element, functioning separately and mutually during the deformation process.
Instead of human input tediously, Python scripts can finish the setup with a large number of grains in GUI (ABAQUS/CAE) satisfactorily by typing given program statements.
In next section, grained heterogeneity will be implemented via Python scripting into each grain with a single plastic property in FE model.
Fig. 1 Voronoi tessellation in bending workpiece (a) 66 grains with grain size 24µm (b) 375 grains with grain size 10µm Grained heterogeneity.
The property of each grain will perform its role in the deformation process, especially the grains in deformed region.

Morawiec1, a 1 Polish Academy of Sciences, Institute of Metallurgy and Material Science, PL-30-059 Kraków, Poland a nmmorawi@cyf-kr.edu.pl Keywords: Grain boundaries; Interfaces; Twin grain boundary; Tilt grain boundary; Coincidence site lattice.
There are a number of classifications of homophase grain boundaries.
Since the accuracy depends on applied experimental methods, the data below are listed for a number of particular tolerances.
[9] Viewpoint set number 41: 3D Characterization and Analysis of Materials.
Conf. on Grain Growth, edited by H.

The number of counted grains was more than 200.
In the present simulation, the number of possible orientations Q was 48 for both the ordered and disordered phases.
A further reduction in grain size was observed when the thickness of carbon layer was decreased, i.e. by increasing the number of carbon layer from n = 1 to n = 4.
The more important point, however, is that all the grains of disordered phase come to be, at least on one side of grain, in contact with the grains of ordered phase and vise versa.
This means that the grains of two phases are well inter-mixed and the sides of their grains are inter-locked one another by the presence of inter-phase, at least, on one side of each grain.

)exp(DH oG ε−= Static and Dynamic Grain Growth in Single-phase Aluminium H.
From such maps, a number of microstructural parameters were determined, and figure 3 shows the crystallite size measured for samples of different initial grain size and deformed to various strains under different deformation conditions.
However, the effect has been noted in a number of aluminium alloys deformed to large strains at room temperature [4,7,8], and has also been found during deformation at elevated temperatures [9], and it is clear that it is a general phenomena.
The grain aspect ratio as a function of strain for all deformation conditions in 3µm grained material.
Conf. on Recrystallization and Grain Growth.

In all instances, the grain size at the end of recrystallization was very fine, D ≤ 2 µm and larger grain sizes were the result of grain growth.
A range of grain sizes 2 µm ≤ D ≤ 50 µm was covered by the grain growth experiments.
The number of pixels per grain size (mean linear intersection) was always bigger than 10 for the images used for grain size determination.
�D D 65.0 ≅ σ (2) N is the number of intersections with randomly oriented lines not crossing any grain more than once.
Grain growth equation.

Most of the materials in nature are polycrystalline materials, which contain a large number of grain boundaries and phase interfaces.
Nevertheless, as far as we know, the influence of grain boundary on the irradiation damage of iron-chromium alloy has not been reported.
It is mixed by a large number of vacancies and small number of interstitials.
Primary radiation damage near grain boundary in bcc tungsten by molecular dynamics simulations[J].
Efficient annealing of radiation damage near grain boundaries via interstitial emission[J].

To determine the rate of inelastic deformation elastoviscoplastic model of polycrystalline metals is used (15): is associated with implicit internal variables of mesolevel characterizing dislocation sliding – shear rate on slip systems , (K is the number of slip systems for the lattice type considered); tensor о described the actual orientation for crystallographic coordinate system of grain relative to the fixed laboratory coordinate system.
To describe the grain boundary sliding intergranular slip systems are introduced in analogy to intragranular dislocation sliding: boundaries are approximated by flat facets, two independent slip systems of grain boundary sliding are introduced for each of them (the double number of slip systems is used), elastoviscoplastic relation with regard to thermally activated motion of grain boundary dislocations describes shears: , (2) where is the (intergranular) grain boundary shear rate under shear stress equal to critical shear stress , Ugb is the energy barrier (for grain boundary shear), is Boltzmann constant, θ is a temperature, H(·) is Heaviside function, is total slip systems of grain boundary sliding.
On the one hand, grains begin to strike on each other under grain boundary sliding realizing that leads to increasing of critical stress.
In the second case more equiaxed grain structure and a grain boundary sliding is facilitated.
Further development of the model is seen in connecting parameters of grain boundary hardening with grain morphology characteristics.

Its microstructure (number and orientation of grains) can be determined by using Euler angles defining the orientation of each grain.
(a) (b) Fig. 6 Effect of the grain shape on the maximum stabilized stress at the global scale during TC load. 3.1.1 Interpretation of results In order to interpret these results, we inventory the number of activated slip systems by grain (ASSGs) during the cyclic stabilization phase for each value of (Table 3).
Note that ASSGs is calculated as the average of activated slip systems by grain, i.e., the total number of activated systems within the RVE in the stabilized state/ number of grains in the RVE.
These results can be explained by the amount of crystallographic slip, i.e., lg (=6)= < lg (=0.75)= despite the number of ASSGs (= 0.75) <number ASSGs (= 6).
These are thus the number of active systems that the amount of slip for each grain.

The formation of the grain microstructure of precision castings is a result of creation and growth of grains nuclei.
According to the nucleation law (1) the number of grains in the casting increases with a growth of undercooling.
Undercooling in front of columnar grains growth is too small for the liquid metal to form equiaxed grains whose growth can block the development of columnar grains layer.
Equiaxed grains block the growth of columnar grains in the airfoil/blade root transition area (Fig. 4 b).
The number of grains in the blade root is significantly lower in comparison to the airfoil.