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High-amplitude and thin-pulse electricity accelerated the nucleation and restrained the growth of the crystalline grains, and as a result nano-sized nickel grains homogenous in size were obtained, which are shown in Fig. 3(b).
The following explanation is as follows: (1) When pulse electricity was employed, existence of the pulse interval hindered the growth of the crystalline grains and changed the growth direction, thus prevented the grains from growing into bulks [4-6]. (2) The size of grains of the deposited layer depended on the velocity of nucleation and growth.
According to the theories in electrodepositing, when the cathode polarization is stronger, the rate of crystal nucleate will increase, and the number of nucleuses will multiple.
However, under the direct current electrodepositing condition, the cathode polarization is weaker, and the numbers of nucleuses are fewer, which will cause the grains to grow bigger and form a rough surface.
SEM shows that the average diameters of Ni grains and AlN particles are smaller.

The reduction of the carbide grain average size was found as well (owing to nanoparticles blocking influence on re-crystallization).
Introduction Strength and tool life of hard metals correlated with their microstructural parameters: volume content of binder and carbides, carbide sizes, mean free path between carbide grains, intercarbide boundaries.
Conventional notions regarding the failure of hard metals composites indicate that the boundaries between carbide grains are very weak structural elements [3,4].
Introducing nanoparticles also inhibits the growth of carbide grains and recrystallization by mass transfer through the cobalt layer, while preventing the formation of intercarbide WC–WC boundaries.
(2) The probability of structural parameters l1 and l2 emergence was determined from: ; , (3) where: n0 – number of particles with volume; n2 – total number of nanoparticles.

The as-forged Ti-45Al-5Nb-0.3Y alloy is comprised of a large number of dynamic recrystallization (DRX) γ grains, curved and broken lamellae, and a small amount of remnant lamellae.
Furthermore, each of grains is comprised of lamellar microstructures (TEM image is shown in Fig.2b).
Metallographic examination shows that, after high temperature forging, the majority zone of the asforged Ti-45Al-5Nb-0.3Y alloy is comprised of a large number of dynamic recrystallization (DRX) γ grains, curved and broken lamellae, and a small amount of remnant lamellae (Fig.4a).
The DRX γ grain size reaches 1~2µm.
After holding at 1320℃,1340℃ for 30min and at 1370℃ for 15min, TiAl samples contain γ and α2 grains, and when it is furnace cooled to room temperature, the phase transformation of α → L (α/γ) → L(α2/γ) takes place in α grains.

But at 700°C the grain size and translucency were both increasing and grain boundaries cannot be clearly distinguished, which means the initial integration.
Therefore, it can be inferred that Vita Alpha powder contains a large number of ceramic components, rather than the glass-based composition.
From the microstructure of sintered ceramic as shown in Figure 3.2, we can see the grains have began to fuse.
The transparency and grain size were also gradually increased.
At 700°C, the Vita Alpha porcelain has showed initial integration and it's individual grains has unable to be distinguished.

The coarse grained tungsten carbides are mainly used in mining or drilling applications.
A reduction of the WC grain size, on the other hand, increases the hardness and improves other mechanical properties [7,8].
In the applied research of ultrafine cemented carbide, Liang Ping[9] and Yu Jiedong [10]et al. showed that ultrafine cemented carbide tool life improved several times over the conventional coarse grain cemented carbide; Pan Yongzhi [11], Kuai Jicai [12] and Zhang Hui [13] et al. indicated that grain refinement significantly reduce the friction coefficient of the ultrafine grain cemented carbide by the friction and wear testing.
Cutting Tool Material Tool materials that were selected for cutting test is YG6 and YG8 with the grain size 2 to 3μm as well as YG6U and YG8U with the grain size 0.2 to 0.3μm.
Thirdly, ultrafine WC/Co cemented carbide tools have a finer grain size, bigger grain surface area, larger volume fractions of grain boundaries twists and uniform distribution of binder phase Co, greater impeding the generation, motion and propagation of micro-cracks, so that the possibility of WC grain being removed reduce, the chipping of cutting edge is more difficult .

Homology analysis In this paper, we used the same method to analyze the fracture surface based on out former paper for prior austenite grains in JIS SUJ2. [8] It is noted that the Betti number is topologically invariable, i.e., while the images of fracture surfaces have a variety of shapes, the Betti number is independent of their shapes.
The values b0 and b1 represent the numbers of red areas and their connection numbers, reaspectively.
Comparing the all Betti numbers b1 of all distances, it was found that the Betti number b1 decreased with stress intensity factor.
(a) Betti numbers, b0 Observation No.
Mizobe, Homoogy analysis of austenite grain size of SAE52100 bearing steel processed by cyclic heat treatment, Apple Mechanics and Materials, Vol. 813, pp. 116-119. (2013) [5] K.

(The average width of the α-SiAlON grains is the mean of the minimum distance passing the geometric center of each grain).
Since the backscattered electron intensity depends mainly on the mean atomic number, the differences in the amounts of neodymium presented in the α, β SiAlON and grain boundary phases make them easily identified.
Grain growth during post heat treatments.
A grain growth was observed in α-SiAlON grains related to high temperature heat treatment and holding time.
Additionally, results of measurement of grain size according to LSW theory showed that grain growth mechanisms are different for width and length of grains.

Reduction by carbon is carried out on the chromite grain surface due to the cations and anions diffusion in the oxide lattice towards the grain surface.
Reduction by carbon is carried out on the chromite grain surface due to the cation and anion diffusion in the oxide lattice towards the grain surface.
A characteristic feature of this model is the formation of reduced metal particles on the surface of chromite grains in veinlets of host rock or along grain cracks.
The rate of metal reduction, the number and size of the metal particles should be the highest in the surface layers of the ore piece.
Chemical composition of reduced metal in the ore “Voltschegorskaya” Sampling point number Element content, % wt.

The reduction in grain size due to the increase of grain density results compressive residual stress.
As shown in Figure 3b, pearlite grains after 6.25% pre-deformation can become barriers for next moving ferrite grain.
The total number of cycles that cause failure is sum of the number of cycles that caused the initial crack and its crack propagation.
The effect of this plastic deformation makes changes in the grain structure become larger, the reaction from the specimen and the environment occurs more in the grain itself, resulting in brittle grains [14].
Number of cleavage surface due to propagation of fatigue crack are found to be many more in number and size (Figures 5c and 5d).

Although observed in various metals of diverse crystal structures, twinning is most prominent in hcp metals, which often have an insufficient number of slip systems to accommodate externally imposed strains [1].
While the twinned grains were refined due to sub-division by the twins, the untwinned grains, which had undergone only slip, had a largerthan-average grain size.
Hence, due to the high stored energy and the large number of high-angle boundaries, heavily twinned regions and particularly the regions of twin boundaries impinging to the prior grain boundaries become favorable nucleation sites for recrystallization.
Texture evolution during grain growth thus appears to arise from the size advantage of the recrystallized grains.
Vol. 50 (2002), p. 1245 12345678910 0 10 20 30 40 Overall specimen (a) Ave. grain size 3.9 µm Frequency [%] Grain size [µm] 12345678910 Grains with CRTC (b) Ave. grain size 3.1 µm Grain size [µm] 12345678910 Grains with RXTC I (c) Ave. grain size 4.2 µm Grain size [µm] 12345678910 Grains with RXTC II (d) Ave. grain size 4.3 µm Grain size [µm]