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Grain Refiner Development for Al Containing Mg Alloys L.
Therefore, the development of a more appropriate, effective and consistent grain refiner is technologically important and necessary but it has not been found yet despite the significant increase in the number of publications reporting potential grain refiners for Al-containing magnesium alloys [17].
Hildebrand, Grain Refinement of Magnesium Alloys, Metall.
John, The Role of Solute in Grain Refinement of Magnesium, Metall.
Taylor, Grain Refinement by AlN Particles in Mg-Al Based Alloys, J.

Moving speed of the abrasive grain at a fixed point in time depends on the path of the grain.
The more deeply embedded in the grain surface to be treated, the more uneven the abrasive grains are cutting part of his profile.
For example, aluminum oxide grain for rounding radius cutting grains: Where - a diameter abrasive grain, mm.
With increasing tip radius of the grain becomes more solid, and the grain begins to cut thicker chips.
The vast number of abrasive grains makes full sections, i.e. when they relate to the treated surface and out of contact with the surface at a depth of cut close to zero.

The average grain size reached to ~ 3mm.
The size of the fine and dispersed particles was only several nanometers and the particle number density (Nv) was very high.
More importantly, the particle number density (Nv) of each alloy is quite different.
There are some particles precipitated on trigeminal grain boundaries which can obstacle the movement between the grain boundaries to some degree.
The main reasons for the good performances are supposed to be the high number density of precipitates, ultra fine grains and the thermal ability ternary phases.

Introduction The grain size, grain size distribution and grain orientation strongly influence the strength, electronic properties and durability of polycrystalline films.
In the presented simulations, only the minima with ηi = 1 or ψ = 1 are considered. m is a parameter related to the depth of the free energy well. p is the number of grain orientations considered in the simulation.
The κi,j and γi,j are related to the free energy of the grain boundary between the grains with orientations i and j and the κi,ψ and γi,ψ to the surface free energy of grain i.
Since grain boundaries move towards their center of curvature, the grain with low surface energy grows at the expense of the other grain.
The equilibrium angles between the grain boundary and the grain surfaces continuously adapt to the new position of the grain boundary.

Ni Grain Boundary Diffusion in Cu-Co Alloys Alexey Rodin1,a, Ainur Khairullin1 1Department of Physical Chemistry, NUST MISiS, 4, Leninsky pr-t, Moscow, Russian Federation arodin@misis.ru Keywords: grain boundary diffusion, Cu-Co alloys, grain boundary structure.
The influence of Co as an alloying element on grain boundary diffusion (GBD) in Cu attracts particular interest due to anomalous GBD of Co in Cu.
Introduction The interest to this problem is connected with anomalous grain boundary diffusion of Co in Cu.
This can not change significantly the situation, because only the saturated solid solution in grains and in grain boundaries can be in equilibrium with a second phase.
Conclusion The study of Ni grain boundary diffusion in Cu and Cu-Co alloys showed that the parameters of GBD did not change with Co concentration.

The measurements showed that achieving the same deformation with the same number of deformation cycles and same heat treatment temperature, the application of shorter heat treatment holding time was advantageous in aspect of grain boundary structure comparing to the thermo-mechanical treatments with longer holding time.
Grain boundaries.
The grain boundary is the surface, where two dissimilarly oriented grains meet, thus the grain boundary is a discontinuity in the crystal.
Grain boundary engineering (GBE).
The aim of our investigation is to clarify the effect of varying the length of the heat treatment processes applying the same temperature, same deformation rate and same number of cycles during the thermo-mechanical treatment.

Also, the coarse grained cBN layer was put on the WC-16wt%Co substrates, and the fine grained cBN layer was put on the coarse grained cBN layer.
Besides, we choose the coarse grained cBN layer can provide fewer obstacles for Co and WC to infiltrate in the fine grained cBN layer.
From the figure 2a, the grain size is about 1-2µm, which is as large as the initial grain size.
When the temperature increase to 1600℃, there are large number of cBN-to-cBN bonding which we strive to fabricate by HPHT sintering process.
SEM examination showed that the PcBN compacts had number of cBN-to-cBN bonding among cBN grains.

Significant degradation is observed in the coarse grain material and a marked sensitivity to the loading level is outlined.
Figure 3 shows the influence of the load level Rf (ratio of maximum applied load and the monotonic load at steady state of bridging) on the variation of φ with the number of cycles for the coarse grained material A20.
What is important is that the threshold of cyclic crack propagation tends toward that of the fine grained material.
Lawn, "Cyclic fatigue from frictional degradation at bridging grains in alumina" J.
Dauskardt, "A frictional wear mechanism for fatigue-crack growth in grain bridging ceramics", Acta.

Kinetics of Phosphorus Segregation in the Grain Boundaries of VVER-1000 Pressure Vessel Steels Boris S.
Parameters of the steel grains Average grain diameter optical metallography (100 ± 25) µm Average subgrain diameter optical metallography (50 ± 15) µm The average number of subgrains in the grain optical metallography 8 ± 3 Average subgrain diameter SEM (2 ± 1) µm The average number of subgrains in the grain SEM (120 ± 30)·103 Average dislocation density 1010 cm–2 Phase Parameters of the phase precipitates TEM SEM V(C,N) The number of the particles in the grain bulk 2·109 2,1·109 Average linear dimension, nm 20 20 Average particle volume, m3 940·10–27 940·10–27 Volume density in the grain bulks, particles/m3 4.0·1021 4.2·1021 (Cr,Mo)23C6 The number of carbide particles in the grain bulk 3.5·107 2.3·107 Average linear dimension, nm 100 110 Average particle volume, m3 5.2·10–22 7.0·10–22 Particle density on the grain surface, particles/m2 4.5·1012 3.5·1012 Volume density, particles/m3 0.7·1020 0.45·1020 Steel samples, having 3.1 mm diameter and ~ 15-20 mm length, with a circular notch
Conclusions The method of quantitative AES analysis of grain boundaries in pressure vessel steel is developed.
McLean, Grain Boundaries in Metals, Clarendon Press, Oxford, 1957
Gurovich, Effect of subgrain structure on the kinetics of phosphorus segregation in grain boundaries, Mat.

Subsequently, there have been numerous reports of superplastic flow in a wide range of Al alloys processed by ECAP including a number of commercial Al alloys.
This trend was also reported for an Al-Mg-Li-Zr alloy [22] and it is reasonable to conclude this is a direct consequence of the increase in the fraction of highangle boundaries with increasing strain and therefore with increasing numbers of passes in ECAP [23,24].
It was observed that the extruded material already contained a fine microstructure with grains of the order of a few micrometers surrounded by even smaller grains at the boundaries but nevertheless the grain structure was significantly refined after processing by ECAP.
Despite the extensive measurements of grain boundary sliding in materials processed without ECAP, there has been only a limited evaluation of the role of grain boundary sliding in materials produced by ECAP and having ultrafine grain sizes.
It should be noted that the phases with white color indicate the Zn grains and those with black color indicate the Al grains.