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In recent years a number of different experimental methodologies have emerged for the study of such microstructures in terms of the individual grains, non-destructively and in three dimensions.
These techniques are generally referred to by the term "grain tracking".
Such techniques may be used to produce 3D maps of grain orientation, to study the dynamics of grain nucleation and growth during annealing, or to measure elastic strain tensors on a grain-by-grain basis.
The grain mapper.
The mapper is designed to work in a number of different modes, depending on the type of measurement.

Micrograded grain structure.
So, the concentration distribution into carbide grain body is more gradually in comparison with grain boundaries.
It is well known that Ti-Nb alloys might undergo a number of phase transformations which can provide metastable phases [10].
In this system no precipitates inside grains were found.
Finally, a non-equilibrium structure consisted of complex carbide (Ti, Nb)Cx grains and β-(Nb, Ti) solid solution located on the grain boundary are formed.

To improve the bioactivity of Ti surface, Ca/P-containing porous titania coating were prepared on the ultrafine-grained Ti and coarse-grained Ti by micro-arc oxidation (MAO) in Ca/P based solution.
The amounts of Ca, P and Ca/P ratio of the MAO coating formed on ultrafine-grained Ti were higher than those for coarse-grained Ti samples.
Influence of grain refinement on the MAO process.
From a thermodynamic point of view, the driving force for the MAO process is enhanced for the UFG-Ti phase, which contained a large number of defects and thus stored a large excess energy.
Conclusions Due to a high defect density and a large number of high-energy grain and sub-grain boundaries, the chemical reactivity of UFG Ti is significantly increased.

We discuss the role of small grains in grain size analysis and derive from the shape of grain boundaries the acting driving forces for grain boundary migration.
Fig. 1: Section of a LASM image of the NEEM ice core (depth: 322 m) – Note the high number of sub-grain boundaries (white arrows) in the vicinity of the air bubble in the upper right corner.
Whether there is normal grain growth (nucleation of new grains is negligible) or dynamic grain growth with a significant contribution of small grains caused by nucleation of new grains is an important aspect as presently normal grain growth is assumed to be the predominant growing mode.
To include small grains affects the mean grain size.
Fig. 2: Profile of mean grain size for different grain size fraction (area filled by grains larger than lower cut-off): 80% (red +), 90% (green *), 95% (blue o) largest grains and all grains (orange x).

Then, the model is adapted from the case of spheroidal grains, considered initially, to the more general situation of ellipsoidal grains.
A combined effect of grain size, grain shape and texture on plastic anisotropy at yielding is illustrated in case of a rolled IF steel sheet.
For a given applied stress within the soft grain, the number n of dislocations piling up against the boundary with the hard grain increases proportionally to the distance dαs of the dislocation source.
This means that the softer grains undergo the following backstress: ταb ≡ (bα ⊗ mα) : σ − eτc0 = √µbτy πdαs (5)The theory was originally applied to equi-axed grains while assuming that the dislocation source is in the grain center.
Barnett: ''Modelling the combined effect of grain size and grain shape on plastic anisotropy of metals'', Int.

During the cooling process of annealing treatment, the number of β phases as perlite-type were increased with the furnace cooling time.
In the early stage of furnace cooling, the β phase nucleated preferentially in the grain near the boundary, only a small quantity of β phase precipitates.In the subsequent cooling process, the rate of precipitate about β phase increased remarked as the time of furnace cooling prolonging, the number of β phase increases dramatically, and the lamellar β phase evenly distributes inside most of the grain.
When the furnace cooling time further prolonged to 2.5h, the β phase continues to extend inside grain, and the lamellar β phase is basically formed inside individual grain.
Cooling to 3h，the number of β phase increases dramatically, and the lamellar β phase evenly distributes inside most of the grain.
But there is still a amount of un-decomposed area near the grain boundaries.

In contrast, for the smallest initial grain size (166 µm) both magnitudes are similar.
If softening processes develop before precipitation occurs, the number of precipitate-nucleation sites (dislocations) will be reduced and the onset of precipitation retarded.
In contrast, increasing the grain size, a reduction in the number of sites available for nucleation of recrystallised grains will lead to longer recrystallisation times.
In the case of the smallest grain size the major density of sites available for nucleation (grain boundaries) leads to recrystallisation start earlier comparing to the above case.
Some level of softening can be reached through recovery processes until the precipitate number density exceeds some critical value and recovery stops.

The paper is devoted to research of influence of “MC-Bauchemie” additions on the fine-grained concrete properties, namely compressive strength.
The results of testing of fine-grained concrete made on the basis of two different natural sands are presented.
Introduction Fine-grained concrete is a special type of heavy concrete in the production of which does not use a coarse aggregate.
Fine-grained concrete has its own characteristics: - composition homogeneity allows to achieve the maximum stone density which means high strength of structures; - the absence of coarse parts of aggregate gives the mix high mobility allowing them to freely pour into hard-to-reach places, densely reinforced structures; - the presence of a certain number of pores has a positive effect on the heat preservation; - low cost of the material (and the combination of components, change of proportions allows to obtain different technical characteristics of concrete as a result).
It should be also noted that the production of high-quality concrete including fine-grained one is not possible without the using of chemical additions [1-3].

The reduction of the grain size leads to an increased plasticity and higher grades of deformability.
However, the effect on the size of grains of the multi-factor impact was not described in literature.
The fine-grained uniform over the cross-section structure was achieved in the AD0 alloy ingots.
This raises a number of the essentially new tasks before the specialists involved in the development of new technologies and their implementations in production.
The method allows obtaining uniform structure with reduced up to several times size of the grains.

Keywords: Microalloyed Steel, Austenite Grain Growth, Coarsening of Carbonitrides Abstract: Austenite grain growth in microalloyed steels is governed by the coarsening of fine precipitates present at grain boundaries below the grain coarsening temperature.
The grain boundary area is the main source of energy for grain growth process; therefore, the system will evolve to reduce its grain boundary area [1].
Larger grains will grow at the expense of the smaller ones.
Although these models are based on a number of physical and geometric assumptions that differ among the models, all of them can be generalized using the following general equation, n crit f r D φ= . (1) where critD is the average critical 3-D prior austenite grain size (3DPAGS), r and f are the mean radius and volume fraction of carbonitrides, respectively, and φ depends on factors such as the geometry of precipitates and austenite grains or coherency between precipitate and matrix.
On the other hand, if precipitates are distributed in austenite at random, due to the low volume fraction of the sample occupied by the grain boundaries, the number of precipitates present in the matrix will be higher than those located at grain boundaries.