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The elongated grains are observed in the parallel extrusion direction and a grain size of ~ 200 µm.
The variation of mechanical properties of 3003 Al alloy with the number of pressings; (a) yield and (b) tensile strength, (c) elongation.
Fig. 3 shows the variation of the mechanical properties with the number of ECA pressing using three routes.
After one pass, the yield and tensile strength increased with increasing number of ECA pressings and work hardening is observed.
Tensile and yield strength for Al billet produced by route A and BC was improved with increasing number of ECA pressings while those for Al billet produced by route C was greatly not changed with number of ECA pressings after one pass.

Once equiaxed grains formed, further reduction in the grain size was not observed with the further cycles.
It is noticeable to find that there is abnormal large grain after five cycles in Fig. 3(b).
Recovery is supported by the fact that the number of dislocations inside grains seemed rather small after five cycles in Fig. 3 (b).
Conclusions Ultrafine grained pure Al sheets with average grain size ~0.5 μm were successfully fabricated by ARB at room temperature.
Tensile strength increases largely with the number of the ARB cycles, reaches a maximum of 228 MPa after the first cycle, and then it decreases to ~210 MPa, beyond that showing a gradually decline with the further cycles.

The specimen and grain size dimensions (in experiments and simulations) were chosen such that, first, the number of grains in thickness was decreased from approximately three to one, i.e. columnar grains.
Thereafter, the number of grains in the specimen width was also decreased towards one, i.e. a single grain in a cross-section.
The extended model of Evers et al. proved suitable for the investigation of grain statistics effects in specimens with a limited number of grains [10].
Schematic illustration of the dependence of the tensile strength on the grain size for tensile sheets with a limited number of grains across the thickness.
• For components with a single grain across the thickness and a considerable number of grains in the other dimensions, the stress level depends primarily on the ratio of the thickness and grain size.

Much of the work has been on the development of ultrafine grained steels.
Therefore, ultrafine grained steels are expected to have higher reduction in area, compared to conventional grain size ferrite - pearlite steels.
The aim of the study was to evaluate the strength and reduction in area balance of these ultrafine grained steels and to verify good formability of ultrafine grained steels.
Although some sub grains and ferrite grains elongated in the rolling direction have been retained, a large number of equiaxed ultrafine ferrite grains surrounded by high angle grain boundaries were observed.
However, among the grain boundaries with low angle grain boundaries of 5°εθε1.5°, high angle grain boundaries of θε15°and middle angle grain boundaries of 15°εθε5°each account for approximately 35% of total grain boundary length.

Since the adoption of the ISO metric sieves thus the old AFS grain fineness number can no longer be calculated and the average grain size, expresses as micrometers (µm) is now used.
The permeability number for moulding sand from Mansfield Sand Company mixed with 6% water is 21 [13].
Effects of Water and Clay on the Permeability Number Fig. 5.
The effect of moisture and clay on the permeability number.
Fig. 5 displays the effect of clay on permeability number of sample.

Therefore, in that work, the specimens were performed with large grains.
Meanwhile, the number decreased gradually.
To further study the fine carbonitrides in the experimental steel, a large number of smaller precipitates were found to appear in the shape of spherical.
The volume fraction of precipitates can be determined by [15]: (2) where N is the number of precipitates per area, S is the specific area for estimation, D is the equivalent dimameter of precipitates, r is the equivalent radius of precipitates.
The influence of grain boundaries on mechanical properties, Metall.

Molecular dynamics (MD) simulation was performed to study the stress induced grain boundary migration caused by the interaction of dislocations with a grain boundary.
A y z x [110] (a) z x y Grain boundary B [110] (b) Journal Title and Volume Number (to be inserted by the publisher) 3 Fig. 2.
The figure suggests that the atoms in the second grain moves downward by the reaction of dislocations at the tube with atoms interfacing the grain boundary in the second grain.
This appears a special case of the high angle grain boundaries and further studies with non-symmetric high angle grain boundaries are necessary for the complete understanding of the stress induced grain boundary migration.
This unusual phenomenon of stress-induced grain boundary migration of a high angle grain boundary is attributed to the symmetrical atomic arrangement of the � = 5 (210) grain boundary.

The severe plastic deformation results in creation of high number of lattice defects.
We have found that microstructure of HPT-deformed Mg contains two kinds of regions: (a) "deformed" regions with UFG structure (grain size 100-200 nm) and high number of randomly distributed dislocations, and (b) "recrystallized" regions with low dislocation density and grain size of few microns.
It has been demonstrated that ultra fine grained (UFG) metals with grain size around 100 nm can be produced by high pressure torsion (HPT) [3].
A number of UFG metals exhibit favorable mechanical properties consisting in a combination of very high strength and a significant ductility.
Typical feature of UFG structure is a high number of defects introduced by severe plastic deformation.

Pittsburgh, Pennsylvania 15213-3890, USA Keywords: Grain Boundary Character Distribution; Grain Boundary Planes; Stereology; Spinel.
In this case, the local maxima are clearly split into two peaks; one is a {111}-type orientation and the other is a complementary plane 40° away.Journal Title and Volume Number (to be inserted by the publisher) 3 MRD Figure 1. l(n), the relative areas of grain boundary planes in spinel, in multiples of a random distribution, plotted in stereographic projection along [001].
In each case, the reference frame is the same as used in Fig. 2 and the circle with the x shows the position of the misorientation axis.Journal Title and Volume Number (to be inserted by the publisher) 5 Discussion The high populations of {100} grain boundary planes in MgO and SrTiO3 have been quantitatively compared to the measured surface energies, which show minima at these orientations [5,6].
For example, since the average number of faces on a grain (13-14) is greater than the multiplicity of the {111} planes, and grain boundaries always have some curvature, it is necessary to introduce non-habit planes in the interfacial network.
Acknowledgment This work was supported by the MRSEC Program of the National Science Foundation under award number DMR-0079996.

It is found when the processing number of the ECP treatment is not greater than four times, the grains are refined and more homogenized, and the texture intensity obtained from the (0002) pole figure appears an obvious enhancement from 11.22 to 22.88.
However, increasing the repeated ECP processing number will cause the coarsening of grain size and the decreasing of the texture intensity.
By adjusting the pass number of ECP at the same current density, the microstructural evolution was investigated, and the related mechanism was also discussed.
With the increasing the repeated ECP processing number, the grain orientation has an apparent rotation and the intensity of basal-type texture presents an enhancement until the processing number to 4´ECP.
From Fig. 2 and Fig. 3, it can be found that when the repeated ECP processing number greater than 4´, the grains become coarsening and the texture intensity becomes weaken.