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Recently, much work has been done in grain refinement of magnesium alloy by severe plastic deformation such as equal channel angular pressing (ECAP) and an excellent elongation to 40% was obtained in AZ31 alloy at room temperature [3].
The average grain size of the α-Mg matrix phase is determined as 22.8±1.2μm, with the remaining β-Mg17Al12 phase (black) distributed along extrusion direction (horizontal).
With the increase of aging time, the second phases at grain boundaries start to grow into grain interiors, with their number and size increase continuously with aging time.
Observation on the precipitates along grain boundaries by TEM (Fig. 4) shows a typical lamellar structure of discontinuous precipitation, which is favorably promoted at relatively low temperatures [5].
The results are summarized as follows: (1) Remarkable discontinuous precipitation with lamellar structure occurs along grain boundaries after artificial aging at 150 oC

In regions where the dispersoid number density is low, the alloy may therefore still be prone to recrystallisation.
As for the Al-Zr-Sc-Hf-(Si-Fe) alloys the pre-screening also concluded that the Hf content should be below ~ 0.7wt% in order to avoid twinned columnar grains (TCGs).
Electron Energy Loss Spectroscopy (EELS) was used in order to measure the thickness of the TEM-foils (necessary to determine the number density of dispersoids), and the average dispersoid size, number density and volume fraction were subsequently determined from dark field images analysed by the software programs Adobe Photoshop and ImageTool.
The poor recrystallisation resistance in alloy 1 can be related to the low number density and heterogeneous distribution of dispersoids.
After 100 hours at 600ºC, however, it had recrystallised completely displaying very coarse grains.

Gravel, coarse aggregate, grain size is 20mm; fine aggregate, river sand, grain size is smaller than 5mm; rebar is HRB335.
Hence, a statistical analysis is based on a large number of experimental data.
This may be related to the insufficient number of experiments and statistical analysis without relevant safety factor of concrete and other factors.
XRD profile and NSC profile are shown in Figure 4, both number of ettringite and its peak increase dramatically as time goes by, it can be observed a large number and developed the peak of ettringite at aged 7d, which indicating that ettringite is the main hydrate during this period.
It is hardly observed peak of ettringite, but can be observed a large number and well-developed peak of C-S-H at the aged of 28d.

Mg alloys have a hexagonal close-packed (hcp) crystal structure and hence a limited number of easy-to activate independent slip systems.
Experimental Results As can be seen in Fig. 1.a, the alloy has an average grain size of 25 µm [6].
Fig. 4 shows the predicted relative activities during these tests inside the grains and twins.
Tensile twinning is activated only by a resolved tensile stress along the c-axis of the grains.
Tensile twinning reorients the twinned region by about 90° from the parent grain orientation. 4.

Cracks evidently propagate along the grain boundaries of columnar grains.
It was found that the crack propagates exclusively along grain boundaries (see Fig. 5).
In this sample, Marble reagent strongly attacks grain boundaries.
Grain boundaries were substantially weakened by the presence of a large amount of oxides.
This was proven by metallographic observation, as the cracks propagated along grain boundaries.

A large number of technological parameters requiring precise control makes the manufacturing process of these steels very difficult.
A large number of technological parameters requiring precise control makes the manufacturing process very difficult.
Austenite grains grow along the ferrite plates, increasing its volume and finally replacing the ferrite in pearlite colonies.
In primary simulations described in [10] equiaxed pearlite grains were assumed.
Deformation of grains during cold rolling was included in the present work and flattened shape of pearlite islands was generated.

On one hand, the number of start slip systems in the grains increases, resulting in the hardening of the material and the increase in flow stress.
On the other hand, the grains turn to the direction which is conducive to the material flow.
The number of the grains on the surface increases and the material flows more easily, leading to the softening of the material and the decrease in flow stress.
Based on the principle of metal physics, the surface grain suffers minor constraints compared with the grains inside.
When the specimen is scaled down, the ratio of the surface grain increases.

A number of AM50 magnesium substrates were coated with RIBAD TiN, using the above parameters but with post implantation time varying between 40 - 840 minutes.
These scans show evident signs of recrystallization and grain growth as the post implantation dose is increased, illustrated in plates a to d of figure 4.
This coating had an extremely fine grain structure with a grain size of ~7ηm.
In this investigation however, the grain growth resulted in a rapid reduction in hardness and wear resistance.
Fukumoto et.al. [9] also reported TiN grain growth with increasing N + dose.

Radon volume activity is the amount of radon that gives the number of radioactive isotope conversions of 222Rn per second per cubic meter, expressed in kBq/m3 [1].
Low gas permeability corresponds to a grain size class content of f > 65 %, for medium soil gas permeability, the grain size class content is in the range of 15 % < f ≤ 65 %, and last but not least, the high gas permeability of soils corresponds to the grain size class content f ≤ 15 % [5].
The third quartile is the 75 % percentile of the set of values and is determined by sorting the set of data on n values in ascending order and the sequence number of the third quartile of set N75 is calculated (refer with: Eq. 2) [5].
The grain size varied between 0.002 - 0.063 mm for dust and < 0.002 mm for clays.
Interesting locality number two is located in the district Ostrava - city on Petřkovická street.

Multilayer coating consists of periodically arranged nanometer thickness layers of different materials, the number of which may be up to several tens.
Discussion Carrying out the process under conditions of ionic bombardment intensifies the processes observed during the deposition of multilayer coatings contributes to a fine-grained structure, nanoscale grains and layers, as well as the formation of complex compounds by: - energy supplied to the condensable coating and converting the kinetic energy of the bombarding ions into heat for the local volumes; - increasing the density and the number of nucleation sites; - activation of plasma-chemical reactions of synthesis of complex compounds by supplying heat directly into the zone of the formation and growth of atoms; - increasing the ionization degree of the condensed stream to reduce the temperature of coating synthesis and to curb the growth of grain sizes, as well as the amorphization of the growing film; - the possibility of cleaning the substrate and the growing film before and during the synthesis of the coating; - stimulation of the diffusion processes at the interface between
In the cavity formed by the parts surface and the screen, the generation of charged particles by oscillating electrons, the number of ions bombarding the surface and the speed of its spraying increase.
In the resulting cavity, the number of ions bombarding the surface increases, the generation of the charged particles oscillating electrons by the workpiece surface and the screen also increases.
Albella, Low grain size TiN thin films obtained by low energy ion beam assisted deposition, Appl.