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Introduction The grain size, grain size distribution and grain orientation strongly influence the strength, electronic properties and durability of polycrystalline films.
In the presented simulations, only the minima with ηi = 1 or ψ = 1 are considered. m is a parameter related to the depth of the free energy well. p is the number of grain orientations considered in the simulation.
The κi,j and γi,j are related to the free energy of the grain boundary between the grains with orientations i and j and the κi,ψ and γi,ψ to the surface free energy of grain i.
Since grain boundaries move towards their center of curvature, the grain with low surface energy grows at the expense of the other grain.
The equilibrium angles between the grain boundary and the grain surfaces continuously adapt to the new position of the grain boundary.

A notable inference was that the variation in grain refinement was not significant with the increase in number of passes corresponding to effective strain values ranging from 1.16 to 4.64.
As the number of passes increase, there is some recovery of the deformed microstructure because of specimen heating before every pass.
A plot of ultimate tensile strength (UTS) and % elongation versus the number of passes is shown in Fig. 4.
This was possible as they were processes augmented by high compressive stresses which lead to higher number of passes (19 passes in case of HE).
The maximum number of passes and effective strain values of the GP and CGP processes were lower when compared to the other SPD processes and hence lower the grain refinement that was achieved.

Si and Mg2Si precipitated in the grain boundary of these two materials.
The weld penetration into the grain of the precipitates and a decrease in the precipitates on the grain boundaries can be considered as reasons for this improvement.
Moreover, an increase in the fine dispersion of the precipitate (Si, Mg2Si) in the grain and grain boundary were caused by the artificial aging treatment.
The fine grains are thought to be related to the increase in strength.
Forging of the artificially aged material produced fine grains and decreases the number of precipitates at the grain boundaries. 3.

The steel structure consisted of large grains of high-temperature ferrite (~ 15%), without visible mesostructured, and martensite packages with a great number of low-angle boundaries.
The grain structure remained stable.
Relatively small number of carbides was detected at CSL special boundaries Σ11, Σ25b, Σ33с Σ41с.
In this case any high-angle boundaries can be considered as special ones, distinguished by the number of grain boundary defects.
Winning, Five-Parameter Grain Boundary Analysis by 3D EBSD of an Ultra Fine Grained CuZr Alloy Processed by Equal Channel Angular Pressing, Adv.

Compared with 20MnSi, steel 20MnSiV boasts much finer microstructure, and large numbers of nanometer precipitates exist in the specimens of 20MnSiV.
Formation of Widmannstatten structure is caused by many reasons, such as chemical composition (carbon content), austenite grain size and cooling rate.
Grain refinement hardening effect can be described by well known Hall-Petch equation (3) where: d is the average ferrite grain size; is constant and its value is 0.55 (17.4N/mm3/2) for HSLA steels.
It can be seen from Fig.3 that large number of nanometer particles exist in 20MnSiV steel, which can provide strong precipitation hardening effect.
(2) A large number of nanometer particles exist in 20MnSiV steel, but this kind of particles can hardly be observed in 20MnSi steel

In the present work, the net pressure on the grain boundaries is based on the summation of the two major driving forces associated with stored energy and grain boundary curvature (different models of grains boundary curvature are presented in the next chapter), but it can be additionally complemented with the possible influence of precipitates [22]: , (3) Then, the equation (2) is considered for each CA cell which is located at the recrystallization front in tth time step: , (4) where: - recrystallization volume fraction in ith CA cell in the t-1 time step, – velocity of the recrystallization front in jth cell from eq. (2), rx - number of recrystallized neighbours, - physical cell size.
In this case, the grain boundary curvature value is determined based on the CA cells states within the extended Moore neighbourhood (Fig. 1a) and is expressed by the following formula: (6) where: a - the side length of the cell in the CA model, N - the sum of the number of neighbours of a given cell, Ni - the number of neighbouring cells that belong to the same grain as the considered cell, A - the aspect ratio depending on the cell shape (rectangular or hexagonal), Kink - a constant equal to 15 for 2D space and 75 for 3D space, respectively.
In this case, the driving force associated with the grain boundary curvature is the primary factor controlling grain growth.
But at the same time, the role of the crystallographic orientation of grains on grain boundary mobility is also considered.
Huang, Grain boundary curvature based 2D cellular automata simulation of grain coarsening, J.

This is because the existence of a sufficient number of isotropic crystal grains in the X-ray irradiation area are based on the X-ray diffraction theory.
From Eq.(1), if the stress plane condition in the sample surface is assumed, the stress components σ11P, σ22P and σ12P can be calculated and decided by the three numbers of ε33L values.
The average grain size is 2.23 mm.
Fig5(a) is for the crystal grain A and (b) is for the crystal grain B.
The blue marks are the results of the crystal grain A and red are of crystal grain B.

Twinned WC grains are sometimes observed in WC powder and sintered WC-Co alloys.
Eta grains were carburized at 700-1450℃ for 1 min to 9 h.
Twinned WC grains formed during the carburization.
A number of investigations have been made on the formation of the twins in WC[2-6].
The types of twinned WC crystals or the carbon position in each sides can be determined by the number of stacking faults in the growing crystal.

Introduction Ultra-fine grained (UFG) metals and alloys with the grain size in the sub-micrometer range may exhibit a number of attractive properties, e.g. high strength and hardness, low-temperature superplastic behavior at high strain rates, improved magnetic properties [1], just to mention a few of them.
†Note that strictly speaking the recrystallization front is not a singular interface, but consists of a number of segments - individual grain boundaries - with own misorientation parameters.
While the C-type experiments do profit from an increased number of GBs that enhance the total GB flux and improvesthe counting statistic decisively, the B-type measurements are almost impossible due to contaminate grain growth.
Application of the back-pressure during ECAP processing (about 200 MPa) suppresses formation of the percolating porosity in Cu, if 4 passes are applied, and the percolating porosity appears again if the number of passes is increases to 8 or 12 [49]
Or they could be consumed by new grains due to recrystallization and grain growth.

To measure the average grain of CCS according to GB 6394-36 [12], three views are taken in the selected region of observation position, one hundred grain size is test in each view.
The more number contained in grain is, the smaller its size is [11].
Its grain only grew, and not to be equiaxial.
The results show that the grain size in cross section of a-Fe phase is from 2 mm to 21 mm, small size grain is enhanced with the increase of the drawing deformation.
[12] The testing method of metal average grain.