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Misorientation Effects on Grain Boundary Grooving of Ni by Liquid Ag P.
On the contrary, GB energies vary in a very wide range depending on grains misorientation and plane position.
Grain size about 100 - 200 µm was obtained.
Randle: The Measurement of Grain Boundary Geometry (IOP Publishing, UK 1993)
Nevertheless, the study of a large range of GBs geometry required the use of a great number of different bicrystals.

These grains are initially formed on the pre-existing grain boundaries and gradually consume the deformed matrix as the deformation proceeds [1-3].
The disparity of substructure characteristics between the deformed matrix and DRX grains can partly be related to the grain size difference.
The organized band substructure observed within the coarse-grained deformed matrix is known to form through a restricted number of active slip systems largely concentrated on a particular {111} slip plane [11].
In contrast, the triple point and grain boundary regions in the fine-grained DRX structure will rapidly spread throughout the grain interiors with increasing strain.
Moreover, in contrast to the original matrix grains, the boundaries of DRX grains are moving while the grains are being deformed until the equilibrium grain size is reached.

The average grain sizes is reduced to 80-150μm under the spiral magnetic field.
The average grain size and the numbers of the dendrites was gradually decreased with the increasing stirring time when the time was not more than 20min.
In contrary, if the stirring time is too much (more than 20min), the primary phase grains aggregate again and the size of grains will become larger.
However, with the further increasing of the exciting current, the grains became larger in size and grew from equiaxed grains to columnar ones.
If the stirring time is too longer or the current intensity is too higher, the primary phase grains aggregate more easily and the size of grains will become larger.

Due to the smallness of the grain size, these NS metallic materials are usually several times stronger than their coarse-grained (CG) counterparts [1-3].
Based on measuring more than 300 grains, the calculated average grain size from the relative number frequency is approximately 22 nm.
Sample Grain size [nm] RTTLN σσ /2 Ref.
On the other hand, due to the strength rise with decreasing the grain size - Hall-Petch relation, the absolute strength rise is much more remarkable at smaller grain size.
As the grain size is reduced to the nano scale, the grain boundary (GB) related activities, such as grain boundary sliding and grain rotation, start to contribute to the plastic deformation significantly [11].

However, the elongation under shear manifested a reduction when the number of ARB passes increased.
A reduction in individual layer thickness was detected with increasing the number of ARB passes.
Furthermore, the number of layers and interface lines are related to the number of cycles and can be calculated with the relationships of 2n and 2n–1 , respectively [14,15].
Notwithstanding that the microstructural evolution in 2024 indicates elongated grains with high aspect ratio, Creation of fine structures was not detected for 6061 with an average grain size of 5 microns.
Both reasons contribute to achieving finer grain size in Al 2024 [16,17].

Polycrystalline laser hosts have a number of advantages compared to single crystals, including higher dopant concentration, cheaper fabrication, and larger devices.
A number of studies have shown that microwave heating often results in superior microstructure with fewer trapped pores, cleaner grain boundaries, and smaller grain size than traditionally sintered materials.
The figure shows the larger micron-sized yttria grains surrounded by the submicron-sized alumina grains.
The grain structure appeared to be 2-5 µm.
The grain boundaries appear to be clean, although there are a number of trapped pores [see Fig. 3(c)].

It has been shown that grain refinement and grain growth occurred simultaneously during the MAC process.
Fig. 3b shows that the fine grains are surrounded by coarse grains with the size of about 20~40 μm.
Hence, the grain size variation during MAC is determined by two factors: grain refinement and grain growth.
When the grain refinement and grain growth reach a balance, the average grain size remains a steady state.
Ai et al. [23] have proved that a large number of the contraction twins emerge and lead to an increased strain-hardening rate after the extension twins completely consume the matrix.

The results indicated that Al microparticles slowly dissolved into nickel grain to form an ultrafine-grained Ni3Al/NiAl composite with micro-sized pores dispersion due to volume shrinkage.
After 3h annealing, both the number and size of black Al microparticles significantly decreased, but gray areas with micro-sized voids dispersion around Al microparticles appeared, as seen in Fig.2c.
From Fig.2d, it can be found that the grain size increased to the averaged ~220 nm.
Thus, the number of alumina nuclei formed on the A-EMC Ni-Al increased with the increasing of annealing times.
In another word, the number and size of voids gradually decreased with the increasing of annealing time, as seen in Fig.2.

This process, grain growth, requires short-range transfer of atoms across the grain boundary.
(2) Here Nα and Nβ are the number of crystallographic orientations in the α- and β phase respectively, and the dependence of ϕα and ϕβ on space and time is suppressed as shorthand.
Four were with 500 α- and 500 β grains, and one was with 150 α and 150 β grains.
The white arrow on figure 3 points to an α grain surrounded by β grains.
The α grain pins the grain boundaries it contacts, while it diffuses through its neighbors.

The loading chips are mechanically removed with abrasive grains and bonding materials from the wheel surface by dressing, and abrasive grains under the previous wheel surface show up.
They are increase with increasing the number of treatment � till the four or five times.
Even if just once wheel treatment is carried out, the abrasive grains can project about one third of grain size.
The number of grinding, in which grinding current is higher than the steady current, increases with increasing the number of treatment �.
The surface roughness decreases with increasing the number of wheel treatment at steady grinding process.