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Due to the weak natural convection, the microstructures are composed of large dendritic grains and fine rose-like grains segregated at the interdendritic regions.
The billet exhibits fine and equiaxed grains.
Thus, large numbers of nuclei disperse within the undercooled melt, which is believed to increase the nucleation rate throughout the melt.
Clearly, increasing the vibration intensity causes a larger Lorentz force acting on the melt, which further increases the nuclei number in the melt and results in great grain refinement of the billet in our experiments.
Crystal grains in the billet have been refined under the electromagnetic vibration condition.

The superplasticity observed in this studied condition may be attributed to mechanisms of dislocation creep mainly within large grains and grain boundary sliding (GBS) of small grains.
A small number of large grains of approximately 20 µm in diameter are embedded in a matrix of small-recrystallized grains about 5 µm in diameter.
The grain compatibility during grain boundary sliding is also required to maintain by some accommodation mechanisms [10].
Moreover, it is also well known that grain boundary sliding is usually considered as a major possible plastic deformation mechanism in fine grains materials, and dislocation activity in fine grains (less than 5μm) is presumably very limited [6].
The mechanisms for superplasticity in present alloy may be a combination of dislocation creep within large grains and GBS of small grains.

Mechanical milling can bring about grain refining and change of lattice parameters.
Cu grain sizes are characterized by the peak of the XRD points of the composite.
The peak 1 and 2 of Cu the grain size peak changing with milling time.
After a long time of ball milling, grain was introduced in serious grain distortion, high density defects and nanometer fine structure, grain at high distortion stored energy state and the sintering activity improved which facilitating sintering densification.
For the composites being milled the grain continued to be refined and grains boundaries increase.

After FEG–SEM observations, these overestimates are mainly due to additional intergranular cavitation along grain boundaries.
It is expressed in term of the number of cavities per unit grain boundary area and per unit time and given by: N0=α'εmin with α'=Naεfin , Na=dgNmπdH (2) For various stress and temperature values, the parameter α' is determined using the image processing software of FEG-SEM micrographs which allows us to measure the area fraction of creep void and the cavity size distributions.
Ten FEG-SEM images (about 250 observed grains) with magnification X500 were analyzed to determine the number of cavities per unit area of polished section, Nm.
The number of cavities per unit grain boundary area, Na, was then deduced using Eq. 2. with dg the average diameter of austenitic grains and dH the harmonic mean of intersected cavity diameter.
The upper and lower bounds of the time to failure can thus be predicted by: 0.301 h(α)kbTΩDbδ∑n2/5ωf0.5164N03/5≤ tf≤0.354 h(α)kbTΩDbδ∑n2/5ωf2/5N03/5 (3) with Ω the atomic volume (1.21·10-29m3 [6]), h(α) the factor which depends on angle formed at the junction of a void and the grain boundary (0.697 [6]), Dbδ the self-diffusion coefficient along grain boundaries times the grain boundary thickness δ (Db°δ = 7.7·10-14m3s-1 and Qb=159kJ/mol [6]) and ωf the critical area fraction of cavities in grain boundaries (0.04 [7]).

It was established that the films annealed at T = 600 °C are polycrystalline with the structure of the orthorhombic BaSi2, with grain sizes of 100-200 nm.
Higher anneal temperature (T=750 °C) leads to increase of diffraction peak intensity of BaSi2 phase with grain coagulated into 300-400 nm aggregates.
For sample 13L the grains with sizes of 100-200 nm elongated in the one direction at root mean square roughness σrms = 6.9 nm are observed (Fig. 1a) that confirms film crystallization and grain texture formation.
For the sample 15R the grains of a circular shape with dimensions of 100-150 nm without preferential orientation were formed (Fig. 1b).
In order to calculate such structural parameters as lattice constants (a, b, c), average grain size (d) and grain micro strain (e) the experimental spectra were fitted by MAUD program [8] taking into calculations above mentioned orthorhombic BaSi2 structure.

The next is that diamond grains are plated and then nickel is plated again.
If the feed load is permanent, the diamond grains density decreases and the depth of the diamond grains into granite increases as the diamond grain size increases.
Table 2 Effect of diamond grain size on slicing process Grain size [Mesh] 170～200 200～230 230～270 Cutting force [N] 3.25 2.99 2.81 Cutting efficiency [mm/min] 8.04 7.68 7.50 Effect of Wire Speed.
If the pressure is permanent, as the wire speed increases, the number of cutting diamond grains increases per second and the depth of the diamond grains into granite decreases.
The depth of the diamond grains into granite increases and cutting efficiency rises as the diamond grain size increases.

For the highest values of stress gradient, the number of points in each bin tails off, leading to large variability.
Scatter plot of average value of KAM in each grain against the size of the grain (291 grains).
No correlation between misorientation and grain size is evident.
Lastly, in order to check whether the development of orientation gradients is related to the grain size, Fig. 6 shows the KAM averaged over all points in each individual grain, plotted against the size of that grain.
No relationship between orientation gradient and grain size was apparent, nor was any correlation with grain orientation found.

The lamellar g¢ phase in the cellular grains was radial, and perpendicular to the cellular grain boundary.
During the manufacturing process of single crystal blades, a number of processes can occur and result in plastic deformation in the material.
When heating time was about 16 h, the depth of CRX was about 35 mm, and the number of lamellar g¢ phases in the CRX increased and the lamellar g¢phases was almost perpendicular to the boundary of CRX.
It can be seen clearly that the CRX consisted of cellular grains, and the interface between different cellular grains was obvious.
The lamellar g¢ phases in the cellular grains were radial and perpendicular to the cellular grain boundary[21].

The experimental recrystallized texture presents a complete γ fiber, with Journal Title and Volume Number (to be inserted by the publisher) 3 a reinforcement of the {111}<110> comparatively to the {111}<112>, stronger than the modelling one.
A relatively good agreement in terms of grain morphology and grain size is obtained.
However, the Journal Title and Volume Number (to be inserted by the publisher) 5 recrystallized texture is not well reproduced.
At the TEM scale [13], the nucleation is observed near the grain boundaries as well as inside grains.
The nuclei grow into the "parent" grains without consuming the neighbouring grains.

This simulation model can be used to optimize forging process chains with respect to grain size distribution as well as cost effectiveness and energy consumption.
Outside of the deformation zone, only marginal changes occur in the modeled physical values, allowing for a simulation that uses a coarser mesh, and thus, reducing the total number of nodes and elements.
The use of the multi-mesh method for this example has lowered the number of nodes and subsequently, the number of degrees of freedom by 48 % when compared to a mesh with uniform element size distribution.
The time saving is lower than the reduction of the number of the degrees of freedom to be simulated because of the additional data transfer operations and the additional memory required by the multimesh method.
The models describing the kinetics of recrystallization as well as the grain size development due to recrystallization and grain growth, introduced by Sellars et. al [5-7], are applied.