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The hardness increase is faster with increasing number of the revolution as reported in other metallic materials [9-12].
Here, the equivalent strain, e, was calculated by the equation as [10] (1) where r is the distance from the disk center, N is the number of revolutions, s is the fraction of slippage and t(N) is the disk thickness after HPT processing.
After the subsequent annealing process, the grain size was measured to be ~125 nm and there was essentially no grain coarsening during the annealing process.
(1) Significant grain refinement form the initial grain size of ~800 μm to ~120 nm was attained by the process of HPT.
This grain size was essentially retained by the subsequent annealing at 583 K for 40 days

Grain of SG or TG grinding wheels is entirely composed of hundreds or thousands micro grains instead more rough structure of conventional alumina grains.
Such structure (SG or TG) favors micro-chipping of grinding grain and keeps grain sharp in the long term point of view.
Except grinding grain structure also bonding of grinding wheel undergoes the process of intensive research.
All analyzed parameters of surface roughness for the surface produced by conventional grinding wheel exhibit remarkable increase along with number of passes and the corresponding conventional grinding wheel wear, see Fig. 6 and Fig. 7.
Surface roughness produced by Norton Quantum stays either nearly untouched along with number of passes or exhibits the gentle increase (in the case of Rqd parameter in Fig. 7c).

The structure consists of distinctly faceted isomorphic grains of three-, four- and six-sided grains.
An average grain size increases to 5.2 µm.
The common feature of Ta containing samples is well faceted grains.
The external habit of grains is determined by metastable rhombic phases.
The fifth cycle reveals a number of anomalies on temperature dependences of real part of dielectric constant.

N is the number of potential slip systems of the crystal: {111}<110> for fcc metals (N=12) and {110}{112}<111> (N=24) or {110}{112}{123}<111> (N=48) for bcc metals.
In practice, the use of the latter is preferred, because of the availability of extremely fast seriesexpansion based techniques for the generation )(aM for a large number of strain modes a [7].
As the LAMEL model, the Grain Interaction Model (GIA) is a cluster model, but it treats a cluster of 8 grains instead of 2 grains [19]. 12 boundaries between sets of 2 grains exist within such cluster.
A B C D E F Grain α Grain β Region 1 Region 2 y1 y3 Fig. 2.
The model operates inside a given grain and interacts with the mesoscopic model for that grain.

However, there were a limited number of reports which deal with the field emission characteristics of the globe-like microcrystalline-aggregate diamond array which was grown in methane concentration of 10 vol % (H2/CH4=100/10sccm) using a microwave plasma CVD system in our laboratory.
It was found that aggregates of the lots of diamond grains were uniformly dispersed on the substrate, and form a globe-like grains array.
Fig 2(a) is the Micro-Raman spectroscopy on the diamond aggregated grains and Fig 2(b) is the Micro-Raman spectroscopy of the substrate among the grains.
The emission current was increased with increasing density of the diamond aggregate grains.
Such results reveal that the electron emission came from the diamond grains.

Creep cracks propagated along grain boundaries decorated with M23C6 carbides and also sigma phase.
In addition to cracks and microcracks propagating exclusively along grain boundaries, Fig. 6, all samples also exhibited numerous cavities and interconnected cavities, occurring at grain boundaries, at triple points and very often at the interface of Cr23C6 carbides or s-phase with the matrix, allowing them to combine and accelerate creep damage, Figs. 7 to 9.
N is the number of cavities per unit area of the metallographic cut (cavities/mm )2 2.
Type K damage refers to cases with minor damage outside the main line of damage; Type C damage refers to cases with scattered cavity formations; at low levels of oriented cavitation (class 3a. lower limit), types K and C may be indistinguishable; Cavity chain = formation with several cavities at grain boundaries (HZ) extending into adjacent grains 3.
Initiation and also joining of cavities is facilitated by the precipitation of Cr23C6 carbides and also by the formation of s-phase, which plays a decisive role in weakening grain boundaries.

To achieve thin sheets, TRC sheets are hot rolled in a number of passes and intermediate annealing depending on the thickness reduction and target gauge.
Therefore, the relative frequencies of fine grain size (<5 µm) and coarse grain size (>10 µm) where accumulated and compared (Fig. 2).
Due to low thickness reduction per rolling pass, the number of dislocations und therefore nuclei for dynamic recrystallization (DRX) is reduced.
This leads to a lesser quantity of recrystallized grains per volume, hence increased grain size, whereas sheet thicknesses of 0.6 mm to 1.0 mm contain more than 50 % of fine grain in their microstructure.
Smaller grains increase the possibility of favourably orientated grains and GBS [28].

Some of those grains had so close orientations that glassy grain boundary between them was replaced by a low angle boundary.
It is widely known that silicon nitride grains grow by dissolution-reprecipictation through the liquid, and grains have a core-rim structure.
Each core acts as a center for the grain growth and each grain usually has one core.
Fig. 6 shows that the glassy grain boundary is missing between the two grains growing from the two separate whisker seeds.
The large elongated grains were highly aligned and part of glassy grain boundary between grains with very similar orientations disappeared.

Methods Fine equiaxed Al-xCu (x=6, 8, or 15 wt% Cu) samples were produced by casting with Al-5Ti-1B grain refiner.
Based on direct in-situ imaging of the loading geometry and microstructure, different initial 2D packing fractions , , were generated in the DEM samples by slightly adjusting the size and number of cohesionless DEM grains.
After the onset, the percolating network was lost, and grains floated until they contacted grains at the top of the sample, as shown in Fig. 1a and b.
The new solid network created by the floating grains has a solid fraction , suggesting that 38% is the approximate percolation threshold for this irregular globular grain morphology.
In contrast, grains in the high solid fraction alloys pushed one another apart during grain rearrangement known as Reynold’s dilatancy [2].

Recently, there have been a number of studies dealing with the electrical properties as well as microstructures and varistor characteristics of SrTiO3 and (Ba,Sr)TiO3 ceramics [2-4].
Acceptor segregating to the grain boundaries in strontium titanate was also observed by Desu and Payne[6].
This leads to an increase of the grain-boundary barrier height, so the V1mA and α increase.
The improvement of the insulation of the grain boundaries results in a decrease of tanδ, and the increase in grain-boundary thickness results in a decrease of εr in that the apparent dielectric constant εr obeys the relation: gr gb(d d )r gb ε ε = (2) where dgr and dgb is the grain size and grain-boundary layer thickness respectively, and εgb is the effective dielectric constant of grain boundary.
As can be seen that the distribution of grain size is uniform relatively and the average grain size is about 3 microns or so.