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The results indicate that the grains of α-Al matrix are fine, the TiB2 particle size is less than 1.5μm, and the agglomeration of TiB2 particles is mainly present at the boundary of α-Al phase, where the mechanical mixture of TiB2 and β-Sn was observed.
It is obvious from the optical photographs that the grains of white-gray α-Al phase are fine in composites(Fig. 1a) as compared to that of matrix alloy(Fig. 1b).
(a) (b) (c) Fig.2 SEM photomicrographs of composites: (a) fine α-Al grains; (b) agglomeration of TiB2 at grain boundary; (c) fractionated gain of Fig. 2b Fig.1 Optical photomicrographs of (a) composites and (b) matrix alloy (a) (b) TiB2 TiB2 The SEM micrographs of composites were shown in Fig.2.
From Fig. 2a, it is evident that the grains of α-Al phase are fine and β-Sn phase lies along the boundary of α-Al phase, but contrary to fig. 1a, α-Al phase appears black and β-Sn phase appears white-gray.
This could be explained as follows: at initial sliding stage, due to large numbers of sharp asperities formed during the machining of the specimens, strong interactions such as cold-rolled deformation, mechanical occlusion and abrasion take place.

The water-jet cutting specimen showed a moderate quality though was seen a trace of abrasive grain.
For water-jet cutting, an abrasive water-jet with garnet grains was used.
The water-jet cutting specimen in Fig. 1(b) also shows a moderate quality of cut though was seen a trace of abrasive grains.
The specimens were obtained the number of repetitions until breaking in the fatigue test.
The water-jet cutting specimen showed a moderate quality of cut though was seen a trace of abrasive grains.

Stability of the substructure of the examined cast steel depends on the morphology of precipitates of M23C6, precipitated on the boundaries of grains/subgrains.
It is many times that cyclic changing impact of temperature and load contributes to the occurrence of deformations and cracks of fatigue character after a certain number of cycles.
A lot of M23C6 carbides of diverse size were located mostly on the boundaries of prior austenite grain and on the boundaries of martensite laths.
On grain boundaries of prior austenite and the boundaries of subgrains there were M23C6 carbides observed.
The interaction of precipitation particles with dislocations, as well as an increase in the number of point defects caused by strain, can lead to the coagulation of M23C6 carbides.

However, it is difficult to avoid residual nanocrystal grains in metallic glass owing to the volume effect.
The CNA analysis indicated that a large number of nanocrystals formed in the metallic glass after a long annealing duration at 490 K.
During the annealing, the change in the number of crystalline atoms of the crystal nucleus was monitored.
Owing to the randomness of the thermal shock, at this state, the number of nucleus atoms leaving the crystal nucleus was inconsistent, resulting in a different number of atoms of crystal nuclei at the beginning of each annealing simulation.
This caused an insignificant increase in the grain size and crystallinity.

Formation of α-Al grains in the composites with the high Si and Mg content was discussed.
When Mg2Si content further increases to 20%, the coarse dendritic crystal gradually breaks into the finer grain with dendritic- like, as shown in Fig. 1e.
In the hypereutectic Al-Mg-Si alloy, there are no α-Al grains formed during the equilibrium solidification.
Due to the dissipating rate of crystalization latent heat is far more rapid than diffusing rate of atom, therefore, α-Al grains are formed in the Al-rich region during the succedent solidification with Mg2Si growth.
Therefore, a great number of Mg2Si nuclei will simultaneously be formed in the melt.

The results proved that adopting micro grain size (W1.5～W36) and high hardness cast iron based diamond grinding wheel, increasing the wheel peripheral velocity (18～20m/s) and reducing grinding depth can effectively improve surface quality and bring the surface roughness down.
It is because that enhancement of wheel peripheral velocity(Vs) make the number of abrasive ,through the grinding area ,increased in the unit time, and the cutting depth of single particle decreased.
(4) Selecting large grain size of grinding wheel to machine the carburized cold-rolled steel by ELID ultra-precision mirror grinding leads to serious burns and scratches on the surface.
In the process of rough grinding, semi-finishing grinding, finishing grinding, the grain size of grinding wheel is in the order of W36, W5, W1.5 in this experiment.
Reducing the grain size of grinding wheel successively, can attain the ultra-precision surface grinding effect of the carburized cold-rolled steel.

It have been investigated the microstructure, structural and phase composition, grain size, physical, chemical and technological properties of powders of alloys obtained by gas-dynamic spray melts.
It require the number of properties of the powders for the above techniques: high purity non-metallic impurities (especially of the surface layer) for the good consolidation during sintering, the spherical shape of the particles, which provide fluidity and high bulk density, which in turn provide the density of green and sintering powders, the absence of internal porosity, which leads to a decrease in strength characteristics and others properties [8-10].
To achieve this goal the following tasks: - The study of the structural, phase, elemental composition, depending on the size fractions; - Investigation of particle size and shape depending on the size fraction; - Study of the grain structure as a function of size fraction; - Investigation of the porosity of particles of different sizes; - Determining fluidity of powders according to size fractions.
Non-uniform grain structure of the particles has the features of rapidly cooled structure with columnar grains, fig. 4.
The grain structure of the alloy powder particles 12H18N10T fraction -90 + 63 microns, etched Table 3.

In Memoriam Dr Steven Rothman (2008), Argonne National Laboratory, USA, who set the very highest standards for tracer diffusion measurements in a large number of metals and oxides including irradiated material.
Dr Patrick Gas (2005), Directeur de Recherche at CNRS, France, who made many important contributions to numerous diffusion problems mostly related to semiconductors and thin films: dopant diffusion, reactive diffusion, grain boundary diffusion and crystal defects.
Jarislav Kučera (2008), Institute of Physical Metallurgy, Czech Republic, well respected for his many significant contributions to diffusion measurements in metals and alloys especially grain boundary diffusion, chemical and reactive diffusion and innovative diffusion measurement methods.

Yield Strength, MPa (VAR4), number of passes (VAR2) and cooling rate, ºC/s(VAR3) relationships corresponding to the steel Ni-Nb(A).
Decreasing the number of passes from 5 to 3 is accompanied by a small reduction in strength - on average 20% - 25%.
However the pearlite colonies and ferrite grain sizes, and also their ratio, depend on HTMP schedules: for n = 5 grain sizes in the range 15-22µm were obtained while for n = 3, the grain size varies between 31µm and 41µm.
The increase in YS when the number of passes increases from 3 to 5 in the case of Tf= 800ºC can be explained by cold-work of the ferrite formed during cooling below the Аr3 temperature.
Namely, a final deformation temperature of 1000 0 C and a number of passes n=5 were selected for these tests.

The average grain size is found to decrease due to aluminium doping.
The obtained grain sizes for Al doped ZnO are smaller than the pure ZnO.
It is found that the packing density is more in the case of aluminium doped zinc oxide for Al 1-1.5 % and less number of grain boundaries.
The average grain size decreases upon doping as tabulated in Table 1.
The increase in the grain boundaries is more in the case of Al 2-5 wt% due to increase in the surface to volume ratio as a result of decrease in the grain size.