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Then, the fiber is run through a container of titanium powder for gluing titanium grains on the polymeric coating (4-fig.1).
For temperatures lower than 700°C, grains in the vicinity of the fiber show that matrix consolidation is not completely achieved (fig. 2 and 3).
After 30 min in this hot pressing 5 4 Impregnation With powder Powder pressing by rolling Recoiling Coiling Cleaning Drying Impregnation with PMMA 1 2 3 Regulator condition, the plastic flow transforms the sharp-pointed grains into equiaxed grains.
When the pressure is slowly applied and reaches 100 MPa, the sharp points of the grains contribute to plastic deformation.
After a number of minutes at 100 MPa, the sharp points are fully deformed and the grains became approximately equiaxed, as previously shown [11].

The microstructure examination revealed the prominent equiaxed coarse grains with the well defined grain boundaries in the heat affected zone due to high temperature of GTAW.
At the fusion interface at AISI 304 side, one can able to observe the coarse grains and well defined grain boundaries of austenitic stainless steel.
The presence of coarse grains on HAZ side of AISI 304 could increase the corrosion resistance property (Fig.1).The larger differences in the hardness value in the weld region as compared to the HAZ region was due to the accumulation of carbides in the region closer to the HAZ and weld interface shown in Fig.2.
Presence of coarse grains found in the HAZ side of the AISI 304 offered high resistance towards the corrosion attack due to the molten salt environment.
After a specified number of cycles the oxides of ferrous and chromium dominates the formation of Nickel oxide.

Its chemical composition shows in Table 1.The refined grains Table 1 Chemical composition of 1050 Al (wt %) Al Fe Si Ca Mg Cu 99.7 0.16 0.04 0.01 0.06 0.03 and initial random texture were obtained by the method of Mao [12] and Raabe et al [13].
Initial orientations and deformation textures were obtained by scanning electron microscope-electron backscatter diffraction (SEM-EBSD).This technique made it possible to determine the orientations of grains.
We assume the stress response at macroscopic continuum material point to be potentially given by one crystal or by a volume-averaged response of a set of grains comprising the respective material point [10].
In case of a multi-grain description the volume averaged stress is ()∑== N k kkw 1 σ σ (1) Where σ represents a volume average of Cauchy stress, N the number of total grains in the polycrystalline, kw the volume fraction of each crystal, and kσ the Cauchy stress in the k th crystal.
F the deformation gradient, * F an elastic part and p F a plastic part.The stress measure which is the elastic work conjugate to the strain measure )1( E is defined as ()()() T− − = ** *)1( det 1 FσFFT (5) where σ is the Cauchy stress in the single grain.

This heat treatment builds up precipitation of Al-Mg phase on high-energy areas such as highly deformed bands and grain boundaries.
Results Figure 1 demonstrates the grain structure of 5182 alloy.
A large number of damage including voids, and damaged second phase particles were seen in these shear bands (Fig. 3).
However at intermediate plastic strain level (11%) some damage of the large second phase particles are observed inside the grains (Figure 6).
Damage is nucleated by large second phase particles which are inside the grains.

According to the reports of recent years [10, 11], small TiN particles, due to their little small misfit with ferrite, can act as nucleating centers to refine crystallization grains of steel.
Experimental results On basis of Fig. 1 which is a scanning electron microscope image of sample 1#, a number of fine particles dispersing in the steel are found.
Figure 1 (b) is the magnification image of the region between the grains of the Fig. 1 (a) .Table 1 is the result of energy spectrum analysis corresponding different sites of Fig. 1 (b).
The particles have specific square form of TiN shown in area (1) of Fig. 2(b), a magnified image of the region between the grains of the Fig.2 (a).
TiN precipitation remarkably refines the alloy grains.

It can be seen that the nanowire arrays with an average diameter of about 80nm are abundantly produced with compact prolate spheroid-like grains, and all the grains are localized in the nanopores of AAO template.
The growth mechanism of nanowires is in accord with that of powders prepared by sol-gel method, and the grains were confined in the nanochannels of AAO template instead.
The nanowire is composed of fine grains with different crystal orientations due to shrinking in the heat-treatment process, and these grains are cylindrical with an average transverse diameter of 17~20 nm and average longitudinal length of 60 nm.
Sample Lattice Parameter (nm) Grain size (nm) Nominal Ni:Mn Experimental Ni:Mn x=0.0 0.83419 10.309 - - x=0.25 0.83507 10.376 3:1 73:27 x=0.50 0.83578 12.010 1:1 48:52 x=0.75 0.83621 13.782 1:3 22:78 Table 1 Structural characteristic values of Ni1-xMnxFe2O4 T=300 K Fig. 2 X-ray diffraction patterns of Ni1-xMnxFe2O4 nanowires within AAO The magnetic hysteresis loops for Ni1-xMnxFe2O4 nanowire arrays with the applied field parallel to the nanowire axes is shown in Fig. 3.
Based on the chain-of-ellipsoids model, from the above SEM and TEM images, the nanowire arrays can be viewed as a segmented chain of magnetic ellipsoids, a large number of magnetic ellipsoids with random crystal orientations may lead to disorderly alignment of magnetic moments.

The original austenite grain size of the sample is about 12μm.
The other one is the austenitic grain size: the grains grow fast when the temperature increases.
While elements are always preferential diffused at the grain boundary and dislocation, carbon diffusion at grain boundary is greater than carbon diffusion at the transgranular [9].
Therefore, the reduction of the number of grain boundary results in the reduction of the diffusion coefficient.

Distinct differences compared to reference clinker were observed, concerning specifically the size and shape of belite grains.
Belite distribution around alite grains was in a shape of fish bone composed of mix of elongated and roundish grains.
Significant reduction in melt viscosity, substitution of Ca and Si by Li [12] and the ability of Li2O to form eutectic mixtures with SiO2 [5] also causes the change in the morphology of belite grains, which become finer forming dendritic structures.
Clinker microstructure at normal cooling rate without addition of Li2O (left) and 0.5 wt. % Li2O (right) – alite forms blue crystals, belite brown nests and interstitial mass form bright areas between crystals and grains (reflected light, polished cross sections etched with fumes of acetic acid) Fig. 5.
With slow cooling, the darker zones of products of decomposition in the alite are visible, the melt contains large number of crystallized dendritic belite crystals (reflected light, polished cross sections etched with fumes of acetic acid).

Modified aluminium was obtained by adding AlTi5B1 grain refiner.
The central group is a material with the addition of AlTiB grain refiner.
The similar situation is in the case of aluminium modified with AlTi5B1 grain refiner.
This is due to grain refinement in relation to the base metal.
It is noteworthy that these properties for aluminium and aluminium with a grain refiner are comparable.

With the increase of nickel content, the volume fraction of white phase decreases, the Fe52Ni48 alloy, besides the phase of white large number of black phase maintains.
We note that the finishing of grain in the alloys 3 and 4 is smaller than the alloys 1 and 2.
Observations by optical microscope assisted by computer MO lead us to deduce that the more the concentration of nickel in the alloy increases the smaller the size of the grains becomes.
Nickel is principally distributed in iron using surface diffusion and diffusion mechanisms at grain boundaries.
Bui, Poly cristaux à grains ultrafins élabores par métallurgie des poudres microstructure, propriétés mécaniques et modélisation micromécanique, 2009