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Eutectic-like colonies (cells) of such precipitation are formed at the grain boundaries.
However, it is not a unique phenomenon, for it is observed in a number of alloys, precipitating by the cellular mechanism.
%Sn alloy the lessening of this fraction with the grain-boundary angle decrease, cellular precipitation starting from this bounadary, is determined.
Dependence of Sn diffusion coefficient of the moving grain boundary on the Sn concentration (∆ - this work, ○ - [8], □ - [16], × - [18], ⊕ - [19]).
Dependence of grain boundary mobilities in Pb-Sn alloys on the Sn concentration.

The number density of Al-nanocrystals has been estimated by counting particles on a dark-field TEM image.
Additionally, the extremely high number of nanocrystals appears to effectively limit the grain growth since particles with an average size of 12 nm are retained.
Synthesis of Massive Nanocrystalline Materials Beyond serving as a consolidation process that allows the production of homogeneous nanostructured bulk materials from rapidly quenched ribbons, a great interest in SPD processing a b exists for developing ways to produce completely nanocrystalline bulk materials with a grain size in the nanometer range and without porosity or contaminants at the interior grain boundaries.
The sample contains small grains with sizes around 50 nm and appears to be fully crystallized after this extended annealing time.
A remarkably small grain size distribution has been obtained with an average grain size of about 50 nm.

The microstructure is equiaxe with an average grain size of 19 µm.
This may be a consequence of interaction between grains during deformation or an accumulation of dislocations in/close to grain boundaries.
Even with the limited statistics due to the small number of recrystallized grains, one can conclude that there is no preferential orientation for the new recrystallised grains, or no oriented nucleation.
In the fully recrystallized state obtained after 240 minutes of annealing at 500°C, the mean grain size is 3.6 µm, with a maximum grain size around 11 µm.
For less deformed areas which recrystallize at last, recrystallization can occur either by SIBM , or by boundary migration of adjacent recrystallized grains and or by sub-grain development inside these grains by extended recovery.

During the durability tests were tested VK6 alloy with the chemical composition of WC-94%, Co-6%, grain size of 2.1...3.4 micron (hardness HRA 88.5) and similar in chemical composition fine-grained hard alloy H10F (WC-90%, Co-10%) produced by Sandvik-MKTS with grain size of 0.5...0.9 micron (hardness HRA 92.1).
The grain size of main carbides, VK6 and VK6M hard alloys has insignificant influence.
Reduction of hard alloy grain is the main trend in structure changing.
Over the past few years, the size of hard alloy grains has been decreased by more than five times [9].
During the durability tests were tested VK6 alloy with the chemical composition of WC-94%, Co-6%, grain size of 2.1...3.4 micron (hardness HRA 88.5) and similar in chemical composition fine-grained hard alloy H10F (WC-90%, Co-10%) produced by Sandvik-MKTS with grain size of 0.5...0.9 micron (hardness HRA 92.1).

Introduction A number of enterprises in Russia that manufacture and use metal parts with hardened surface layer is continuously growing.
We have no information, how ultrasound will act if there are grains of different matter, not only metal.
Thus in case when size of a grain is larger than the wavelength it can reflect the sound.
In order to investigate this, it is necessary to prepare samples of different structures for the experiment: 1. fine grained 2. middle grained 3.coarse grained Fig. 3: Micrographs of Steel The experiment will be conducted on samples with coarse and fine structure.
Such changes will allow to measure depth of hardened layer in large number of heavy-loaded parts, components and machinery. 3.

The results showed that secondary extrusion could result in significant grain refinement and the grain size increased with extrusion ratio, which the minimum average grain size was about 5.4μm in the alloy under λ=12.25. 
The grain size was determined using a linear intercept method from a large number of non-overlapping measurements.
As can be seen, some fine grains usually distribute among three or more large grains and the average grain size is determined to be about 22.8μm.
The average grain size with different extrusion ratio is shown in Table 1.
So that the dynamic recrystallized grains will grow faster under higher billet temperature and then coarse grains should be observed in the alloy with larger extrusion ratio.

Introduction Grinding is a material removal process where a large number of arbitrarily positioned abrasive grits pass across workpiece to remove material in forms of tiny chips.
It was proposed that upheaval or residual stock removal caused by the effect of grain shape and cutting speed, and effect of elastic deformation of grain.
Matsuo et al [16] in their experiment with wet condition the CBN grain generated as large pile-up as diamond grain.
The cutting path of single grain FEM simulation is illustrated in Fig. 1.
A typical mesh of the grain and workpiece is C3D4 element which is a four node linear tetrahedron elements are used to mesh both single grain and workpiece part.

This resulted in substantial grain size refinement in the titanium accompanied by significant property improvement.
The resulting grain growth causes a loss of hardness and a decrease in mechanical strength.
The reduction of grain size to nanostructure in titanium rods requires multistage extrusion with low reduction rates.
Therefore, a smaller number of passes is necessary to obtain the required deformation or shape (diameter size) of titanium rods [4,5].
The surface treatment enables the number of hydrostatic extrusion passes necessary to obtain a nanostructure in titanium to be reduced.

The decrease in the number of significant violence after the PWHT process occurs at 700°C, which is equal to 187.7 HV in the weld metal area and at 138.6 HV in the heat affected zone.
Item Grouping Sample Material Diameter Item (mm2) Grain Number Weld Metal Without PWHT 0.0363387 2 600°C 0.03115 2 650°C 0.0311834 2 700°C 0.029825 2 Heat Affected Zone Without PWHT 0.0242678 2 600°C 0.036328 2 650°C 0.0363387 2 700°C 0.036368 2 From table 1 the heat affected zone the grain size grows with each increase in the stress relief annealing temperature.
Whereas, in the weld metal area the change in grain size is unstable.
When the heat treatment process occurs grain growth, ferrite grain growth is controlled by temperature and holding time.
Holding time affects the increase in grain size, so the longer the holding time, the grain size will also increase [9], [10].

And the composite layers consist of AlN particles and nickel grains both nanometer-sized. 1.
Experimental The average grain diameter of nano AlN powder is 50nm.
According to the theories in electrodepositing, the stronger the cathode polarization is, the faster the rate of crystal nucleation, and the more the number of nucleuses.
Therefore, the layer can be obtained with a compact surface and fine grains.
When the nucleating grew faster than the growing rate of the grains, the grains fined. 4.