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Y2O3 (purity>99.9%, grain size is about 6μm) was used as sintering aids.
The grain boundary phase was Y2Si2O7 in the samples sintered at 1450℃ and 1600℃.
Y2Si3O3N4 and YSiO2N were the grain boundary phases of the samples at 1550℃, 1650℃, and 1700℃.
The hexagon β-Si3N4 grains began to arise in Fig. 4(b).
The growth of β-Si3N4 and large numbers of linear grains resulted in bulk expansion, and then the reduction of bulk density, as shown in Fig. 3(a).

The number of factors known as causes for separation [5] in our case of low-impurity steels with predominantly bainitic microstructure can be reduced to two general causes: microstructure banding (whatever it is caused by) and cleavage on {100} planes [6].
Grain size determination can be done using several approaches in EBSD data post-processing software.
Both methods indicated that the central layers of the pipe wall have larger grain size than the sub-surface ones.
The degree of microstructure elongation, or morphological anisotropy, can be estimated by the relation of two abovementioned grain sizes.
The average grain diameter divided by the average intercept length is defined as a parameter determining the degree of morphological anisotropy.

The IBP addition on ceramic surfaces did not decrease the number of osteoclast colonies and appeared to improve the performance of the HA as a surface for osteoblast culture.
Introduction Bisphosphonates have become the drug of choice for a number of clinical applications characterized by an excessive bone resorption for which no previous treatment existed.
The presence of secondary phases and an excessive grain size should be avoided on the ceramic body [8].
Ceramic bodies examined with SEM display a mirror-like surface with grain sizes under 1 micron and a medium surface roughness of 0.08 μm.
The BP addition did not decrease the number of osteoclast colonies and appeared to improve the performance of the HA as a surface for osteoblast culture as shown in figure 1 right.

Takao.et.al [7] found that slip band in a grain of carbon steel was nearly equal to the grain size in early stage of fatigue process.
N and Ni mean number of cycles and fatigue crack initiation cycles, respectively.
In this study, fatigue crack initiation is defined when the fatigue crack in a grain reaches a grain boundary and starts to grow in Mode I.
Therefore the grain size can be defined as the initial crack size in carbon steel.
Average ferrite grain size df (=20μm) was regarded as half-surface crack length, a.

In the process an aluminum rod claded with a copper tube was extruded repetitively three times where a number of the single extruded rods were bundled together and subjected to hydrostatic extrusion to obtain multi-filament wire bundle.
Second, recently, HE is applied to fabricate nanostructured or ultrafine-grained metals starting from metallic bulk or by powder consolidation [4, 5].
Hydrostatic extrusion of commercial magnesium alloys at 100 [degree sign]C and its influence on grain refinement and mechanical properties.
A study of hydrostatic extrusion as a consolidation process for fabricating ultrafine-grained bulk Al-Mg alloy.

The form of the welding groove and the number of welding passes of double-connected pipes are shown in Figure 3.
(a) Groove Form (b) Number of Passes of the Welding Layer Fig. 3.
Groove form and number of passes of the welding layer.
The grain size of the coarse grain area is relatively large, up to 122 μm.
To sum up, although the grain in the coarse grain area is large, the toughness can be guaranteed.

The number of nuclei in Fig. 1 left and middle and right is the same: 100 nuclei.
Clearly the reaction is faster with an increasing x1 as the number of nuclei increases.
The agreement is quite good even though CA grains do not have spherical shape.
Matern cluster process The important parameters[6] in a Matern cluster process are: a)λp, the number of clusters per unit of area; b)nc number of points per clusters and c)R, the cluster radius.
The total number of nuclei per unit of volume is simply λpnc = 1250.

Fig. 1 RVD grain shape The use effect of this kind of abrasive is not good.
The Characteristics of CSD Diamond The Grain shape Characteristics of CSD Diamond.
Each grain contains a number of tiny particles with the different size.
These small particles are known as the sub-crystal grain.
Each sub-crystal grain size is between several microns to dozens of microns.

Since under the same experimental conditions, the plastic deformation of crystal grains of different orientations are not the same, even in different region of the same grain, plastic deformation is not the same [7]。
At initial process of the surface-nano, plastic deformation occurs in the first orientation of the grains of some of the slip-prone, but due to the plastic deformation of the grain boundaries having a certain impediment, so that the plastic deformation of crystal grains in the same layer is uniform.
The figures show that, after a nanometer processing, copper alloy surface tissue was refined, and the processing time is longer, the grain size is finer, and surface-treated for 10min, the nano-size grains on sample surface had little microstructure difference than the treated samples for 20min
This universal rule of thumb is suitable to the grain size of the crystalline material from the ordinary to several hundreds of micrometers, that is, with the decreasing of the grain size, yield strength (or hardness) are increasing, they have a linear relationship with .
When H68 alloy after surface-nano processing, grain refinement occurred significantly, the number of grain boundaries increased and interfaces to increase, while the surface stress on alloy surface increased, makingcopper alloy surfaces in an unstable state, the copper alloy is immersed in aerobic ammonia oxygen corrosion occurs in the surface layer of CuO or CuO / Cu (OH) 2 passivation film, the higher the surface energy, the trend is more obvious for the formation of passive film, the more dense passivation film is formed, and in the electrochemical corrosion test measured corrosion potential is higher, the better the corrosion resistance.

On the other hand, nanocrystalline (NC) materials and ultrafine grained (UFG) materials describe polycrystalline materials where the grain size (all or average) is below 100 nm and 1 µm, respectively [3, 4].
In NC materials, a large fraction of volume consists of grain boundaries or interfaces [4].
Atoms located at grain boundaries tend to behave differently from those within grains, and thus the properties of NC materials deviate quite significantly from their coarse grained counterparts.
The inverse relationship between strength and grain size in metals follows the well established Hall-Petch relation.
Powder metallurgy provides a convenient way of introducing variations in both scales and number of phases.