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The unique compacting mechanism of the HCP leads a number of characteristics such as a higher compacting speed, wide applicability for net shape formation, etc.
Introduction A number of mechanical and other properties of structural materials are widely affected by state of the microstructures.
The mean length of intercepting lines between grain boundaries on the cross section is multiplied 1.78 times to estimate the grain size, assuming the grain shape as α－ tetrakaidekahedron[22].
No abnormal grain growth is observed.
Fig. 8 Grain-size / relative-density trajectory of HCP alumina.

In addition, the grain of recycled materials are wrapped up in the face by a powder layer.
The grains of brown alumina and zirconium mullite are whole, except that some grains of recycled materials are wrapped up in the face by a powder layer.
While There are apparent porosity in the face of some grains of fused silica. 1.3 Process of making samples The formulas from F1 to F4 are shown as Table 2.
The grain of recycled materials are wrapped up in the face by a powder layer.
(3) The grain of recycled materials are wrapped up in the face by a powder layer.

Firstly, nano-crystallization in surface layer of pure titanium was carried out by high-energy shot peening, and then the shot peening with small diameter shots was introduced to degrade the surface roughness, enhancing the quality of the nano-grained surface.
Because titanium and its alloys do not have 5 slip systems required by the Von-Mises law for materials to deform continuously without cracking, the formation of tiny cracks and holes can be caused along the boundary of twins and grains during the plastic deformation.
The chemical compositions of the pure titanium（Wt%） O N C H Fe 0.09 <0.05 <0.10 0.010 0.18 Figure 1 Shape and dimensions of notched specimen Table 2 Specimen Serial numbers, Conditions of shot peening, Roughness measured Conditions of shot peening Anneal Normal shot peening High-energy shot peening Combined highenergy shot peening Specimen Serial number A SP HESP RESP Ra（µm） 0.97 5.32 4.40 3.16 Figure 2 Surface morphology by SEM Figure 3 Surface roughness layer of commercial pure titanium was formed by high-energy shot peening with bigger balls [8]; In the next step, second shot peening on the surface of specimen employed by the low energy smaller shots to decrease surface roughness and to improve the quality of nano-grained surface effectively.
The serial numbers of specimen by shot peening with various conditions, the results roughness of specimens surface measured by the T1000 surface roughness instrument were listed in the table 2.
To SP, though the grains sizes in the surface layer did not transform to the nanometer level by shot peening, but the workhardening and, compressive residual stress was caused in the surface layer by shot peening.

A sharp change in the physical and mechanical properties is observed when the resource Ni/Np = 0,3-0,4 and Ni/Np = 0,7-0,8 is reached (where Ni/Np is the ratio between the current number of cycles when measured and the number of cycles till failure).
In order to determine the critical number of cycles, the first specimen was cycled till failure.
The average grain size was determined during the measurement with further plotting of dependence of the average grain size on the level of accumulated damages, which is given in Fig. 5.
Dependence of the average grain size on the level of accumulated damages after static tension away from the failure zone The indicated dependence shows that the grain size within the period Ni/Nр = 0...0,7 decreases.
Also, one of the indicators of the structure degradation is the increase in the number of micropores.

XRD method was used to analyze the crystal structure of the samples, and SEM was used to observe the topography, grain’s size and ceramics density.
The giant permittivity is attributed to electrons inside grain and insulated grain boundary.
It is known that in perovskite ABO3, the coordination numbers of the A site and the B site are 12 and 6, respectively.
Significantly, the inside of crystal grain will be semiconductive by the bringing electrons, and to result in the maximum permittivity [12].
The average grain sizes from the LN1 to LN4 are 0.47 μm, 0.50 μm, 0.66 μm, 0.53 μm, respectively. 4.

Because the number of the simultaneously engaged cutting inserts in turning and milling is fewer than that for grinding, to obtain high machining efficiency, depth of cut in individual cutting inserts should be much larger than in grinding.
High quality and high efficiency machining can normally be achieved by using a machining tool with a reduced size but an increased number in its cutting edges.
SiC grain Whisker Wear in Machining.
(a)Contact between the whisker edge and the SiC grain (b) Fractured SiC grain (c) Micro porosity formed by the SiC grain removal.
Its diamond grains are connected by the C-C covalent bond.

SEM/EDAX and TEM results indicated that the co-deposited CeO2 or Y2O3 particls were homogeneously dispersed in the finer-grain nanocrystalline Ni grains.
The RE ions in alumina scale, either segregated to the grain boundaries or moved toward the gas/oxide interface along the grain boundaries, block the outward Al diffusion via the grain boundaries, causing the decrease of the scalling rate and reducing the interface voiding kinetics.
Due to the solute-drag effect by RE ions or the precipitates, the scale-grain boundaries would be pinned [20], and fine-grained scales with enhanced adhesion could be retained.
Third, the CeO2 or Y2O3 particles themselves in the coating might act as sinks for vacancy condensation[9, 15], which decreased the number and size of vacancies at the scale/coating interface or in the coating.
Cyclic oxidation of an ultrafine-grained and CeO2-dispersed d-Ni2Al3 coating [J].

Grains.
The same leather type and color were the the selection criteria of grains.
These 3 kinds of popular cowhide grains were Smooth, Litchi, and Floater.
Hense, there were 5 kinds of grain specimens totally.
The preferences for grains.

Depending on the crystal structure, several types of granite can be distinguished: · coarse - grain diameter greater than 5 mm · medium-grained - grain diameter is 5 to 2 mm · fine-grained - the diameter of the grains is not more than 2 mm.
The strength of these materials depends on the grain size.
Granites with a fine-grained and medium-grained structure (Fig.2) are distinguished by high strength (ultimate compressive strength up to 3000 kg / m3, volumetric weight 2740 kg / m3).
To assess the process of layer-by-layer destruction, the number of experiments in one cycle is determined (Eq. 1)
(1) - is the displacement of the point of force application, - is the number of sectors, - the value is constant for each cycle, but increases with decreasing [11-12].

An increase in C content resulted in the decrease in the grain size and the increase in fcc-structure lattice parameter.
This is partially because of the overlapping of peaks from main and minor phases and partially because of a limited number of weak peaks from the minor phase.
The formation of small grain sizes gives rise to a high density of grain boundaries.
Increasing the density of grain boundaries can diminish dislocation activity, thus resulting in grain boundary hardening [9].
Increasing C content results in the decrease in grain size and the increase in fcc-structure lattice parameter.