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Obviously, the ECAP process refines the grain.
As shown in the Fig. 1, the ECAP processing refines the grain.
On the other hand, the number of grain boundary is increasing with ECAP processing, which lead to the increasing number of sensitive site for pitting corrosion.
Thus, the corrosion resistance of specimen is decided by the competition between the current magnitude of glavanic cell and the number of glavanic cell.
The superiority of grain boundary is weakened.

All results, including grain size, texture, and grain boundary characteristics, were based on the analysis of no less than 4000 different grains.
During recrystallization and grain growth, the magnetic field creates an additional driving force for grain boundary migration between adjacent grains.
In addition, grains with higher susceptibility grow at the expense of other grains during magnetic annealing.
The results of the current study are in accordance with previous reports by Zhang et al. [15] and Harada et al. [16], who explained that annealing samples magnetically produced fewer low-angle misorientation boundaries as an effect of reduction in the number of dislocations.
(3) Pulse magnetic annealing can accelerate dislocation motion and decrease dislocation pile-up, thus reducing the number of low-angle grain boundaries due to repeated magnetostriction induced by application of a pulsed magnetic field.

The TiC0.3N0.7 grains in preforms deposited on three kinds of substrates all took on anomalous equiaxed grains.
The grain size of them was all less than 3μm.
When with 45 steel as substrate, it took on near equiaxed grains.
During the metal spray forming process, the cooling rate of metal droplets was usually in the number order of 106℃/s[6-8], which was lower for one number order than that of the reactive spray forming process.
The growth of TiB2 grains along the c axis has been limited, which made it hard to form rod-like grains structure.

The interior of these new grains is free of dislocations.
ation method refines structure across Al plate in dependence on the number of passes performed and/or on level of strain introduced.
TEM microstructure analysis results indicate that there is a very low fraction of submicron grains with high angle grain boundaries even in case the strain applied is the highest.
A distinction between the values for the initial state and the deformed plates subjected to CGP straining due to the different number of pressings evident.
In order to clarify the CGP effect on grain refinement, transformation of subgrain boundaries to high angle boundaries and appearance of a small fraction of dynamically recrystallized grains, all these structural changes may substantially contribute to modification of plastic deformation of strained Al specimens, as regards the number of pressings.

If a misorientation of few units of degrees is allowed in each grain, the total number of grains in the explored area has been calculated to be around 2.4∗10 3 and 2.2∗10 3 for sample A and B, respectively.
Moreover, the grains are preferentially oriented so that the ϕ2 values are strongly peaked on 0o and 180 o while the φ for most of the grains has two peaks around 30 o and 150 o .
In this specific case, each grain possesses a strongly anisotropic CTE.
The thermal expansion coefficient is a second rank symmetric tensor, in which the number of independent components is linked to the crystal symmetry of the material.
The grain orientation distribution in the two films has been studied by means of electron diffraction.

With increasing number of ECAP passes and cold rolling reductions, the initial coarse grained structure in the as-received material was transformed gradually into an ultrafine grained microstructure with an average grain size of 0.2~0.3 µm.
For convenience, the tensile specimen is addressed with two letters followed by a number.
The first letter indicates the plane, from which the specimen is cut, and the second indicates the tensile axis, and the number indicates the layers number of the plane, as show in Fig.3.
Microstructure heterogeneity is clearly shown, especially for the case of pass 2, where the distortion of the grains in the microstructure increases with the layer number.
This is confirm in the present investigation by observing the distortion of grains after ECAP.

However, magnesium has a hexagonal closed-packed (HCP) crystal structure with a limited number of operative slip systems at room temperature, and its formability is restricted to mild deformation.
Some grain boundary areas contain small recrystallized grains.
The annealed microstructures (Fig. 5(d),(h)) consist of equiaxed grains with relatively clear grain boundaries.
In general the grain size becomes finer with increasing number of pass and decreasing deformation temperature as shown in Fig. 6(b-d),(f-h).
In general the grain size becomes finer with increasing number of pass and decreasing deformation temperature.

The present study aims to examine the tribological characteristics of the ultra-fine-grained dual phase steel.
The grain size of the ferrite grains is ~20 µm and the pearlite grains with the size of ~10 µm are distributed relatively randomly.
The microstructure of the ECAPed low carbon steel which is characterized by UFG ferrite grains with high density of lattice dislocations, subdivided pearlite colonies, and a large number of boundaries with extrinsic boundary dislocation [5] is suggested to provide the uniformly distributed austenite nucleation sites, and to accelerate the partitioning kinetics of carbon and manganese, which resulted in the uniformly distributed martensite islands along with equiaxed ferrite grains.
The martensite islands also restrained grain rotation, which impeded the coarsening of ultra-fine grains.
It is reported that the grain boundaries of the severely deformed monolithic materials are so unstable that coarsening of the ultra fine grains easily occur during wear, which results in high wear rate in spite of their high hardness [6].

The structure of austenitic steel before and after 25% of total number of cycles of low cycle fatigue tests conducted at room temperature is studied using TEM.
The X-ray analysis [2] showed that the value of microstress weakly depends on number of cycles.
It is recognized that main role in fracture process [6] play dislocation structure, grain boundary precipitates and grains of δ-ferrite [7-8].
In some grains the deformation twins are found to be grouped.
However, there are some grains without twins, or their number is too small.

An adequate microstructure was defined as displaying a small number of grain boundaries and a high amount of γ’ in the joint.
To judge the results regarding the grain boundaries the following characteristic number was used: A grid of parallel lines perpendicular to the brazing seam was projected on the joint area and the intersections of these grid lines with grain boundaries were counted.
To gain a number independent of the evaluated length of the joint, the intersections were divided by the number of grid lines.
This means if the number equals zero, no grain boundary developed in the joint and the value one means one grain boundary or several grains are located in the joint.
Regarding the grain boundaries developed in the joint, all samples are similar except one in which developed on average three grains boundaries in the joint.