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During Superplastic deformation crystallographic texture usually gets randomized because of random grain rotation.
Figure 2: Comparative bar chart of volume fraction of different texture components present in surface and middle layer Figure 1: The ODFs of the two layers before forming; a) important FCC texture components, b) ODF of surface layer and c) ODF of middle layer a) b) c) The randomness number of ODFs is indicated on top of each ODF.
The texture weakening with strain is typical of superplastic deformation wherein grain boundary sliding with random grain rotation randomizes the texture.
The textured middle layer support initial deformation by slip mechanism and, after recrystallization through grain boundary sliding and grain rotation [4].
Bate, The absence of relative grain translation during superplastic deformation of an Al-Li-Mg-Cu-Zr alloy, Metall.

A large number of grain boundaries will decrease the efficiency of a device since they decrease the mobility of an electron.
Grain Size Measurements.
We are interested in calculating the grain size of CdTe since it is the top layer of the superlattice and thus we can verify the calculated number by using the TEM.
Fig. 10 shows that the grain size ranges from 30 to 50 nm and Fig. 11 shows that the grain size ranges from 70 to 175 nm.
The values are in good agreement with the calculated numbers.

It is concluded that impurities (such as CaO and CaCO3) effected the porperties of CaF2, the grain size is smaller, the corrosion resistance is lower.
Introduction Precious metals smelting in China currently faces a number of problems regarding its serious environmental pollution, energy wastage and the poor purity of the smelted product.
The molecules number of per unit cell is four, the cation sublattice is face-centered cubic structure, anionic sublattice is composed of simple cubic structure.
Other materials with this structure include a number of materials used as nuclear fuel, i.e.
But A certain amount of defects was appeared from the Fig.4(c).Too many defects and small grain were appeared from the Fig.3(d) and Fig.4(d) when the samples were soaked in 10mol% HF solution for 24 h.From this result,we could conclude that impurities (such as CaO and CaCO3) effected the porperties of CaF2, the grain size is smaller,the corrosion resistance is lower.

The measurements [6] were performed with an accuracy of 0.01 mm and numbers of loading cycles N were recorded.
Oxygen is an element stabilizing α-phase, and this phase is dominating in the top layer as almost equiaxial grains.
In deeper layers, poor in oxygen, participation of β-phase increases, and grains of phases α and β become more elongated.
In the core, stripped structures were obtained for all the specimens, which characterized the big grains of the primary β-phase.
Let us note that the cracks are not continuous and they occur mainly in the grains of phase α (light grains, Fig. 4b), and their course proceeds in a transcrystalline way.

Elongation primary grain (PG) and boundary of subgrains (SB).
In FeAl alloy complete recrystallization is observed with average grain size of Ā=1440 µm2 (d=42,8µm) (Fig. 6b).The distribution of misorientation angles indicates a great number of narrow-angle grain boundaries with a relatively small misorientation angle (30%) (Fig 7a).
Conclusion In their initial state (after casting and heat treatment), the Fe3Al-Cr and FeAl intermetalic phase based alloys had coarse-grained single-phase structure with diversified grain size.
Deformed at a temperature of 1100°C has a large number of narrow-angle boundaries (below 15°), and typical strong texture.
In the FeAl alloy with a higher aluminium content 38% at Al, fine recrystallised grains forming on the boundaries of the primary grains and their number increases with the rise in the process temperature.

The grain aggregration with columnar structure were obtained from FE-SEM.
A small fine grain was observed at deposition time of 30 min (Fig.2a) whereas the coarse grains developed with contained faceted grain were found as reach to 90 min (Fig.2a and 2c).
Not only the refinement of grain but also evolution from fine to facet morphology were observed from FE-SEM results which come from a larger number of deposited atom/molecule arriving at the substrate as increased deposition time resulting increased adatom mobility and formation of nucleated cluster during deposition [9].
The effect of average grain diameter predicted that the increase hardness as the grain size decreases obtained from the Hall-Petch relation [12].
The grains aggregation and re-arrangement were observed as increased deposition time.

The quality of castings cast under pressure is influenced by a number of factors.
The area of structure formed out of a single nucleus is called primary grain.
Amount and size of grains depends on number of crystallization nuclei.
If during the solidification only a small number of nuclei is activated, the result is a coarse-grained structure and vice versa.
Dependence of amount of grains on crystallization parameters is determined by the relation as follows: (2) with: N - amount of grains [-], a - diffusional coefficient of proportionality [m2.s-1 ], n - number of nuclei [-], vk - linear speed of crystal growth [m.s-1], V0 - primary volume of liquid phase [m3].

Introduction For converting a coarse-grained material into an ultra-fine grained material, it is necessary both to impose an exceptionally high strain in order to introduce a high density of dislocations and for these dislocations to subsequently rearrange in order to form an array of grain boundaries [1-4].
This technique can be applied to commercial pure metals and metal alloys, with FCC, BCC and HCP crystal structures with coarse grains, to fabricate ultra-fine grained materials or nanomaterials that have no porosity and superior mechanical properties compared to the non-processed material [5-8].
Langdon, Principles of equal-channel angular pressing as a processing tool for grain refinement, Prog.
Butu, Mechanical behavior and microstructural development of 6063-T1 aluminum alloy processed by equal-channel angular pressing (ECAP): pass number influence, JOM, 64 (2012) 607-614
Higashi, Ductility enhancement in AZ31 magnesium alloy by controlling its grain structure, Scripta Mater., 45 (2001) 89-94

Route A denotes no rotation between two successive passes; route B imposes a rotation of 90° after each pass and distinguishing for either clockwise or counterclockwise rotation depending on the pass is even or odd numbered and C denotes a rotation of 180° after each pass.
Nine numbered sensors, as shown in Fig. 4, were defined in the billet with the purpose of the analysis of the strain path followed by the material in different zones of the sample.
The main axes of the grains rotate after each strain pass.
For the present specific ECAE application an empirical grain fragmentation procedure [16] plus a grain subdivision criterion [10] was implemented in the VPSC code.
The grain subdivision criterion consists in splitting the grain in two or four sub-grains if the ratios L/S (single split) or L/S and M/S (double split) achieve a critical value R.

From the map, by checking the distance between the various points, it is possible to estimate the effect of: (i) T6 precipitation on an undeformed sample; (ii) solid solution hardening and precipitation hardening, both on deformed samples, (iii) number of ECA passes, and (iv) annealing temperature.
In all cases Al2Cu precipitates were detected, some on grain or sub-grain boundaries.
On the other hand, the furnace cooled samples are characterized by coarse precipitates, mostly located along grain or sub-grain boundaries rather than within the grain.
The other parameters are the level of ECAPdeformation and the concurrent grain size reduction, both opposing dislocation accumulation.
(iv) Differences of the fine microstructure associated to different deformation severity (1X and 4X) exerted only a small effect on precipitate size, which is in the range 35 - 50 nm; the still wavy and ill defined nature of the grain (or sub-grain) boundaries precluded accurate measurements of grain size, except for sample 4X170, estimated as ≈ 200 nm.