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Equiaxed grains about 20 nm are seen.
Submicron size equiaxed ferrite grains and cementite particles precipitated at grain boundaries are seen.
re-austenitized submicron-grained layers.
Recovery is easy to occur for SS dislocations since same number of different sign of dislocations distribute randomly.
The grain boundary energy of per unit volume of ferrite with grain sized of 100nm is given Eg = 37 2 1 m/J104.1 d 4 ×= ⋅π σ (1) where, σ is the grain boundary energy per unit area (0.6 J/m 2).

The BLT thin films were found to crystallize preferably either with (001)-oriented or randomly oriented grains depending on number of coating layers, substrate size and heating process.
When the number of coating layer increases the grain orientation tends to be random.
The heating process also affects grain orientation of BLT.
The AFM images of randomly oriented BLT thin films deposited on 10 mm × 10 mm substrate show rod shape grains lie on random directions.
When the number of coating layer increases the grain orientation tends to be random.

Its structure is complex, consisting of clastic structure and grain structure.
The latter refers to the fine grain chemical precipitation (micrite), which is from water.
This topological dimension with integer value is denoted by, which determines the numbers of the independent coordinate or the numbers of independent direction of a point in the coordinates [8].
The non-empty boxes are numbered as .
Firstly, numbers of boxes can be obtained through appling different corresponding.

Diamond powder with grain size of 1 µm was used as polishing material.
Microstructure of the alloy WE43 in initial state is formed mostly by equi-axed grains with smaller size of grains than in the case AZ31 alloy.
In the region of grain boundary the occurrence of intermetallic phases may be expected.
· After ECAP processing the fined grained microstructure of the alloys AZ31 and WE43 was achieved.
Continuous Severe Plastic Deformation Processing of Aluminium Alloys, Final Technical Report, DOE Award Number: DE-FC36-01ID14022, 2006, p. 1- 68

In the contrast with extruded AZ31(Figs.3 (b)), a number of secondary cracks and two group shear bands can be observed on the sample surface, which parallel or perpendicular to the main crack.
Comparing (a), (b) and (c), it is easily to find with the extension of annealing time the number of twin increased.
Twinning can only be found in coarse grains.
This is because dislocation need long glide in coarse grains, also stress concentration is more serious in coarse grain boundary than close grain.
For extruded AZ31, grain size play a greater role than twinning in plastic deformation, it is found that the larger grain size, the lower yield and higher strain hardening exponent.

At last in minor numbers of spectra the peak broadening exceeds 1.5 cm-1 so that two-component structure of the diamond line becomes obvious (Fig.2d,e).
The stress mapping within the surfaces of a number of individual grains has been reported in detail elsewhere [12].
The stress distribution study in a grain bulk was the next step.
In the second case, when identical atomic layers of the two grains form different angles with the coalescence direction, unequal number of the layers terminates at the common boundary from both sides.
To stack the layers the grain lattices should be deformed during the growth process so that one grain will be expanded and another one will be compressed.

An increase of the number of passes results in increased texture sharpness.
Moreover, based on a big number of experimentally identified twinnings in the cp-Ti, one can suggest an essential contribution of twinning process in ECAP-deformation of the metal [12].
The identified type and intensity of texture formed in the 1 st pass do not change essentially after the next passes, which was explained by a limited number of slip systems in the hexagonal lattice of Ti [13].
The presented microstructures revealed strongly defected state of material with visible grain boundaries.
The plane becomes a plane of separation between the active mechanisms of deformation as the number of the ECAP passes increases.

This improvement is related to a change of grain size/morphology, chemistry of intergranular phase, SiC particles distribution, and structure and chemistry of grain boundaries.
The composite additionally contains globular nano- and submicron-sized SiC particles, intergranularly located between Si3N4 grains and intragranularly in the Si3N4 grains.
No pores, clusters of grains/phases were identified in the microstructure of the nanocomposite.
They hinder the grain growth of the Si3N4, changing the shape and chemistry of the grain boundaries and grain boundary phases.
The intergranular SiC nanoparticles hinder the Si3N4 grain growth, interlock the neighbouring Si3N4 grains and change the volume fraction, geometry and probably also the chemical composition of the grain boundary phase.

While in most high performance systems, the number of GPUs is less than the number of cores of CPUs.
The outer parallelization exploits the coarse-grain parallelism across mesh blocks.
And the inner parallelization exploits the fine-grain parallelism inside mesh block.
For exploiting coarse-grain parallelism, the process spawns threads by employing OpenMP.
In the inner parallelization, the GPU exploiting the fine-grain parallelism by using CUDA, and the CPU spawn threads to exploit the fine-grain parallelism by using nested OpenMP.

Introduction Engineering ceramics, also called structure ceramics, such as silicon nitride, zirconia and alumina, are promising materials for a large number of high-technology engineering applications due to their excellent properties, including high strength at elevated temperature, low thermal expansion, good wear resistance, chemical inertness and so on[1].
Therefore, it is necessary to reestablish the model of grinding force for a single grain in ultrasonic grinding process.
Supposing that S is the contact area between grinding wheel and workpiece, and λ is the density of cutting points, the number of active cutting points N can be calculated as 3 2 g 2 0 02 π 6 π       ⋅== v d K RSN λ (3) where K0 is the coefficient affected by grain shape and dressing conditions; vg is concentration of grain; R is the radius of the end of a diamond grain; d0 is the average diameter of diamond grains.
Therefore the impulse of a grain PI on the workpiece is tN ftAfM N F P ∆ −== )π2sin(π4 22 t I (4) Supposing that W is resultant force impacted on the grinding wheel without ultrasonic assistance, the resultant grinding force of a single grain Pj equals to W/N.
The grain size of the wheel was 350# and the wheel velocity was 35.3 m/s.