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Grain refinement and superplastic deformation behavior of Zn-Al alloys were investigated in this study.
There have been an extensive number of reports on superplasticity the various classes of materials including metallic materials, ceramics, and amorphous alloy. [4-8] Zn-Al alloys have also been reported to exhibit an excellent superplasticity. [9] Equal channel angular pressing (ECAP) is very effective way to obtain a fine grain size in crystalline materials by imparting severe plastic shear deformation. [10] In the present work, it was attempted to obtain a fine grain size in Zn-0.3Al alloy by employing ECAP and to evaluate the superplastic characteristics of the alloy.
It is apparent that in the as-cast specimen grains are very coarse and irregular and the grain size of warm rolled specimen was observed to be about 30 mm.
The strain imposed in the ECAP process can be expressed as the following equation (2), where N is the number of passages and are described in Fig. 1. [14] In the present study, the strain after a pass of ECAP is calculated as 0.62 and the strain rate as about 1.3´10-1 s-1.
Conclusions To obtain fine grain size in Zn-0.3Al alloys, ECAP process was successfully employed in this study.

The paper considers the problem of improving fine-grain concretes production technologies.
Materials and Methods The application of 3D-technologies creates the possibility of constructing buildings and structures of any shape or number of floors, or original architectural expressions.
Components of fine-grain concrete compositions № Number of composition Binder Type of main aggregate Fine aggregate Coarse aggregate 1 1 CEM I 42.5N Nizhneolshansk sand granite macadam 2 2 CEM I 42.5N QS crushing screenings – 3 3 CB QS crushing screenings – 4 4 CB QS crushing screenings, Nizhneolshansk sand – Prototype samples were made of the mix with the necessary content of all components, including the construction composite and the modifying admixture, which provided the optimal phase composition of hydration products (Fig. 2).
During the whole curing time a number of alterations in the material’s structure take place, due to the artificial contraction, decrease of porosity and prevention of flowing deformation.
For fine-grained concrete on a composite binder with high-density packaging, creep decreased by more than two and a half times compared to fine-grained concrete on cement.

The nucleation rate is the number of grains nucleated within a given time in the untransformed unit part of the parent phase.
It was assumed that after the transformation the grain size number (m) of the finest austenite grain structure would be a maximum of 10, NA = 8192 grain/mm2 (Eq. (11)), and thus on the simulated area the maximum number of developed austenite grains can be 1/2.84*10-3≈23.
The average areas of grains were 23.28 µm2, 36.41 µm2 and 76.76 µm2, the number of grains/mm2 (NA) were 42957, 27464 and 13028, and the grain size numbers (m) were ~12, ~11 and ~10.
A linear curve is kept for the nucleation rate as a function of grain size number (m) (Fig. 7b).
a) b) Fig. 7. a: Number of nuclei in a unit area as a function of time, b: nucleation rate as a function of grain size number The effect of carbon concentration.

During recent years, a significant number of studies have been carried out to study recrystallization kinetics and texture evolution during hot rolling [1, 2].
The fraction recrystallized is obtained from the number fraction of pixels in grains that have a GOS value less than 3°.
The volume fractions of different texture components in deformed and recrystallized regions were calculated from the average orientation and number of pixels in each grain.
The average orientations of grains are also used to determine the texture component of the each grain and weighted with the number of pixels of that grain to obtain the corresponding volume fraction.
This is also evident from the analysis of the number fraction of pixels of cube recrystallized grains against the deformed grains.

This bar was numbered pass 0.
The roll passes in the wire rod block were numbered from one to eight with the odd numbered being the oval passes and the even numbered the round passes.
For the determination of grain size a minimum number of at least 200 grains and 8 data points per grain has been recommended [5], and these recommendations are followed in this study for both grain and subgrain size determination.
Results and discussion The mean size for all grains (>10°), the recrystallized grains and the subgrains in deformed grains are shown in Fig. 1a.
(b) Map of recrystallized grains growing into a deformed grain after pass 7.

Mode I and Mode II Fracture Toughness Testing for a Coarse Grain Marble M.R.M.
A series of fracture toughness tests have been conducted on a type of coarse grain marble.
A total number of 22 CCNBD specimens were tested successfully under mode I conditions.
Specimen Number 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 KIc , KIIc (MPa m 0.5 ) 1.0 1.5 2.0 2.5 3.0 KIc (Test Data) Average value of KIc KIIc (Test Data) Average value of KIIc Fig. 4: Mode I and mode II fracture toughness of tested CCNBD specimens made of coarse grain marble.
The average value of σt reported for typical coarse grain marble is about 4.7 MPa [14,15].

Enhancing nucleation in the initial stages of solidification can increase the latter number of α-Al, where this can be achieved through using high cooling rates or adding grain refiners like TiB2.
Addition of Mn and Al-5Ti-1B grain refiner will enhance heterogeneous nucleation in the Al melt, thus this will aid in the prompt growth of α-Al grains.
The average grain size is shown in Table 3, for alloys I and II.
This is explained through an increase in the latter number of grains, as both Mn and TiB2 cause for there to be an increase in latent heat of extraction.
When there is a small grain boundary area, the liquid film around the grain envelopes will be significantly smaller and thinner [2,7].

Despite much activity in this field, only a limited number of studies were focused on the mechanism of grain refinement during severe plastic deformation [3,4,6,7].
In the presented data, Journal Title and Volume Number (to be inserted by the publisher) 3 200 µµµµm (a) 100 µµµµm (b) 1 µµµµm (d) 100 µµµµm (c) Fig.1.
Most of these grains exhibit elongated shape, since the equiaxed new grains were also observed.
Upon further strain the number of deformation-induced boundaries within areas locating between initial boundaries or extended medium to highangle boundaries increases.
A dynamic equilibrium is reached, i.e. the number of generated LABs with θ≤5 o and the number of annihilated LABs with these misorientations are essentially the same.

Introduction Many damage mechanisms of polycrystalline metallic alloys involve the accumulation of plastic strain and rotation at the sub-grain level, particularly in the vicinity of grain boundaries.
These bands increase in number and intensity with increasing stress level.
A limited number of 6 grains named G1 to G6 are analyzed in the present article.
This slip/strain bands distribution appears to be inhomogeneous within grains and may be directly correlated with the vicinity of double or triple grain boundaries.
Localized strain bands are observed to be often continuous across grain boundaries.

The surface grain is nano-size, and the grain size is about 10nm to 20nm.
Experimental results and analysis Fine single-phase austenite equiaxed grains accompanied with a large number of annealing twins can be observed after solution treatment (Fig. 2(a)).
A large number of new extremely fine grains are generated by the slip(Fig. 3(b)).
In Fig. 3(c), the grinding time of friction head is increased to 6 hours, no clear grain boundaries are seen we can see that between the grains has no clear distinction between the grain boundary, grain refinement to a certain extent and formed a large number of clusters flocculent microstructure.
It demonstrate this part of the grain is nano-scale grain.