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So in commercial point of view there is a need to reduce the strain and number of passes required to produce ultrafine grained structure by ARB processing.
The region shows grains in the size range of ultrafine grain material by definition i.e., grain size range 200nm-800nm.
The grains are fairly equiaxed in shape.
It is proposed that large number of dynamically recrystallised grains form in the material at the end of 2 pass ARB itself and they are more copious in the 3 pass ARB.
(a) (b) (c) (d) Conclusions Al-2.4wt%Cu-0.3wt%Si alloy was conventionally rolled to a rolling strain of 2.46 followed by accumulative roll bonding process to different number of passes.

- 1 - A Study on the Manufacture of Aluminum Grain Refiner by Flux Reaction M.
Studies on the grain refining ability of Al-5wt.
Fig. 5 (b) shows the effect of reaction temperature and holding time on the number of TiAl3 particles.
As you see, the number of particles tends to decrease with the holding time and reaction temperatures.
Fig. 5 (a)Size and (b)Number of TiAl3 particles as a function of holding time at the various reaction temperatures.

Two distinctive groups of materials fall into this category: Nanocrystalline (NC) materials with grain sizes up to 100 nm, and ultrafine-grained (UFG) materials with grain sizes ranging from 100 nm - 1 µm [5, 6].
ECAE processing is generally described by the number of extrusions and the so called processing route.
The impurities in the material of commercial purity further stabilize the microstructure by pinning the grain boundaries, resisting grain coarsening and grain boundary rearrangement.
Slight changes that occur upon cyclic deformation include more well-defined grain boundaries and decreased dislocation density in the grain interiors.
It should be also noted that the grain size observed in the TEM is smaller than the grain size obtained from EBSD measurements.

In this case, ferrite grains in the range of 1-3µm were produced and a much more homogeneous distribution of these grains was present.
At least 200 grains were counted so as to give proper representation of average grain size and 95% confidence limits.
Clearly, ferrite grains present in sample deformed at 915 o C are coarser and distributed in a what seems a bimodal way with a population of grains of the order of 4-5 µm and another with grains around 10-11µm.
Less than 10% of the total number of grains counted was of sizes larger than 5µm.
It seems plausable then to conclude that SIT of γ into α grains generated finer and more uniform ferrite grains.

It is mainly observed in metals and alloys with cubic face-centered lattice, characterized by a high number of slip systems (Al, Cu, Ni) [4].
At this temperature the total number of 3 passes was applied.
The mean grain size is about 1.9 mm, what indicates that two additional passes of ECAP caused almost 2.5 times reduction of grain size.
The microstructure is mostly composed of small equiaxed grains and only few larger grains with a high density of low angle boundaries can be detected.
The average grain size is about 1.9 mm.

The average grain size after strain application was 0.5 µm.
As a result, 67µm equi-axial crystalline grains were obtained.
The current study result also supports the high grain-size dependency on yield stress that has been reported in crystalline grain refining methods [1-3].
At the same time, we have deduced that, although low-misorientation grain boundaries and high-misorientation grain boundaries are formed in parallel in uniaxial working, by making the working multi-axial, the intersection of the low-misorientation grain boundaries divide the inside of the original grains finely and uniformly, which consequently form a nearly equi-axial grain structure in high strain regions [1-3, 5].
Conclusions An increase in the number of strain paths is most effective for the easier evolution of ultrafine grains in high-strain working.

Because the stored grain insect action sound are to weak too be detected, and also affected by the environment noise, the effective extraction of insect action sound has become the key of the stored grain insect sound detection.
The design ideas of the sound insulation chamber The stored grain action sound is the sound generated when insects, which grow in the stored grain heap, feed stored grain or creep in stored grain.
The stored grain insect feeding or crawling sound is generally as a unit with a pulse.
Because the stored grain system contains both solid structure and gaps, the sound wave is the multi-mode wave and mainly propagates through the gap of grains[2].
Sound detection of stored-product insects that feed inside kernels of grain.

BEHAVIOR OF GRAIN BOUNDARIES UNDER DEFORMATION Grain boundaries can respond to stress in a number of ways. [2] They can act as dislocation sources by emitting dislocations into the neighboring grains.
In addition to transferring stresses and strains, the boundary itself can deform by a number of processes.
Slip continuity, expressed as percent in Fig. 1, was defined as the ratio of the number of slip traces across a boundary divided by the total number of slip lines impinging at the interface.
The localization of strain leads to a mismatch at the grain boundary; called a “deformation ledge.” [11] Das and Marcinkowski characterized the deformation ledge by an “effective” Burgers vector B, given by: (1) B = n(b1-Qb2), where b1 and b2 are the Burgers vectors in grains 1 and 2, respectively, Q is a rotation matrix, and n is the number of dislocations that enter the boundary.
In the case of localized deformation and channeling, dislocations pile-up at the grain boundary in only a small number of widely spaced locations, increasing n and therefore, B.

The variations in the structure of the material are obtained by changing the load applied on the roller and by increasing the number of passes.
Microstructure describes the grain refinement in ARB processed materials.
ARB of dissimilar alloys shows layer thinning and grain refinement [6].
Ultrafine grain size was achieved through ARB process.
Bonding between the layers was successful only after a required number of cycles.

On the other hand, the number of research works as to SPD of commercial medium carbon steels is still limited [6], because SPD processing is relatively difficult in steels with higher flow stress.
Grains of pearlite with size of ~ 50 μm are lined by the finer ferrite grains (~10 μm in diameter).
These pearlite grains are lined by finer ferrite grains, Fig. 1a.
Finishing ECAP deformation the corresponding effective strain in dependence of number of passes was εef = 2.7, 3.4 and 4 respectively for individual samples.
The deformed microstructure, which resulted from different ECAP straining of steel, related to different number of passes through die channel 500 nm (N= 4 and N= 6 passes) is presented in Fig. 4.