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Rotation of grains leads to emergence of high local internal stresses.
Rotation of grains leads to emergence of high local internal stresses (fig.3).
So, high chemical activity of gallium turns this technological task into a sufficiently complicated process which depends on the number of both positive and negative factors.
Mass transfer of gallium into Al alloy between grain (SEM).
The diffusion results in an intense growth of grains sizes and volume of the detail, in shifting of old grain boundaries and formation of new ones.

At lower deformation, these bands are parallel and start and terminate at the grain boundaries.
As the strain level increases, the number of the twins band increases and they intersect each other.
This figure shows also the presence of annealing twins in some grains, specially in larger grains, which give evidence of a low value of the SFE in the alloy.
At lower deformation (Fig. 3a), it is observed a microstructures of nearly equiaxed grains with straight deformation twins present only in a few grains.
The major gliding activity is located in the not twinned austenite grains.

With nitrogen rate (168 kg/hm2), irrigation (90 mm) in jointing stage, and irrigation (70 mm) in heading stage, grain yield was higher.
Five factors were showed by capital letter (A, B, C, D and E) and four levels were showed by number in right hand of capital letter respectively.
It also showed that irrigation was main factor of improving and ensuring crop grain yield in arid region.
Therefore, the optimum combination of higher GY grain yield was A2C1D2.
Grain water use efficiency (GWUE) comprehensively reflected the relationship between water consumption and grain yield.

Decreasing of the titanium grain size increases the number of ways for new phases formation, due to the facilitated diffusion of alloying elements.
The smallest grains of oxide phases with up to 20 nm are localized at dislocations in the volumes of the target grains.
With an increase in the grain size, we detected increased thickness of the Ti3Al grain and primary localization on the board of grains.
There is an ordered Ti3Al phase in coarse-grained titanium targets (17 microns), localized in the form of interlayers not only along the grain boundaries, but also in the body of α-Ti grains.
In titanium with grain size 1,5 mm TiAl3 phase particles localized along the matrix grain boundaries.

Spherical grains can be obtained by several semisolid processes in aluminium alloys.
As the dislocation density increases, there will be more grains for recrystallisation.
Thus, grain structure will be more refined [2].
Spherical grains of 7075 (a) treated at 575oC for 35 min (b) treated at 600oC for 20 min Fig 2 shows the SEM image of the spherical grains of 2024.
Comparison of the elongation at fracture results for 2024 and 7075 alloys Fatigue tests were applied after PH process to several numbers test bars in both quenching mediums (Quenching in RT Water / RTW-Q and Quenching in Boiling Water [80°C] / BW-Q after SHT).

Most of these effects are related to the nanometer-scaled grain size.
Carbon will pin dislocations and grain boundaries, slowing down the dynamic recovery process.
This is in contrast to the ductility which is limited by the number of inclusions.
The number of inclusions and the purity content are correlated.
An increasing amount of impurities leads to a higher number of non-metallic inclusions, restricting the intrinsic ductility.

The strength of Cu-Ag alloys is determined by a number of strengthening mechanisms, which to a certain extend influence each other.
Work hardening originates from the cold work, that is applied in order to prepare the wire in its final dimension, and thus takes into account both, the increasing number of dislocations and the decreasing grain size.
Perpendicular to the drawing direction, i.e. the shorter length scale of the grains, a mean grain size in the order of 100 nm is estimated by TEM analyses.
From Fig. 5b primary recrystallised grains can be seen, which have a mean grain size right below 100 nm.
However even coarsened grains are observed after annealing the sample at this temperature.

Microstructure evolution and tensile properties were studied in a bainitic pipeline steel grade by performing a number of physical simulations on samples machined out of an industrially produced transfer bar.
During the rough rolling the austenite grain size is refined due to repeated cycles of work hardening and the recrystallization process.
The austenite status at this stage - regarding the prior austenite grain size (PAGS) and precipitation - simulates the condition of austenite after the roughing process.
On the other hand, a value of 60 s for tV was enough to attain the saturation point for large prior austenite grains deformed at high temperature (Fig. 5b and 5e).
Summary Microstructure evolution and tensile properties were studied in a pipeline steel grade API-X80 by performing a number of physical simulations on samples machined out of an industrially produced transfer bar.

For the non heat treated samples, glassy regions were revealed, by centered dark field images, using diffuse scattered electrons, to be located at three and four point grain junctions.
Stress exponents near unity, related to grain boundary accommodation processes were obtained for low temperatures and for heat treated samples.
The deformation processes in these cases were correlated to stress concentrations at grain boundary and triple point junctions, caused by grains rotation and sliding, accommodated by cavitation.
For a series of materials in the Si-Mg-O-N systems it has been deducted that creep can occur by a number of mechanisms, including (6,19,20) diffusional creep, cavitational creep, grain boundary sliding accommodated by the elastic deformation of constrained grains and hardening due to compositional change induced by oxidation.
Clarke: Techinical Report, AFOSR Contract Number F49620-77- C-0072, (1978)

A small number of laser shots and a low temperature of substrates (series 1) probably slowed or stopped the processes of diffusion and coalescence of the already grown grains, which caused the situation that substrates were not uniformly covered with BN.
Registered grains have similar, small sizes (Fig. 1).
The morphology and phase maps of boron nitride coatings An increase in the number of laser shots, the energy of laser and the power of the RF discharge generator (series 4) cause that the substrate is completely coated by boron nitride; moreover, a larger variety of the size and shape of grains can be observed, as a number of quite large grains with an elongated shape have appeared.
On the surface of large grains and among them, a significant amount of small grains can be observed.
Such variation in conditions resulted in the noticeable growth of the grain size.