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It had been reported that repeated induction heating process decreased the prior austenite grain size and refined the martensitic structure of JIS SUJ2 samples.
In the case of repeated quenching, Mikita reported that amount of insoluble carbide decreased with the number of quenching time in JIS SUJ2 steel [6].
He reported that repeated induction heating refines grain size [7].
Mizobe et al. [10] stated that repeated furnace quenching refined the prior austenite grain sizes in JIS SUJ2 bar.
Refinement of grain size is not found by Nital etching.

It was found that tested ZnAl40Cu(1-2)Ti(1-2) alloys are characterized by homogeneous, fine- grained structure.
Results of examinations The tests carried out on optical microscope showed that all of the tested alloys have a fine grain, dendritic microstructure.
Their size and number increased with increasing of titanium content in the alloy.
Due to this fact is achieved a more fine-grained structure and a more homogeneous.
ZnAl40Cu(1-2)Ti (1-2) alloys are characterized by uniform, fine-grained structure. 3.

Moreover, the number of research works dealt with superplasticity of these alloys is very limited [5-7].
Partially recrystallized structure consists of grains with an average size of ~0.9 μm and elongated ribbons of initial grains, which are subdivided by transverse boundaries.
It is worth noting that continuous grain coarsening under static annealing [12] occurs through the growth of grains with Bθ/θ initial orientations at the expense of grains with Aθ/θ and / orientations (Fig. 8a).
In gauge section the last is indicative for operation of grain boundary sliding [3] that leads to elongation of grains along tensile axis (Fig. 8c).
Humphreys, Continuous and discontinuous grain coarsening in a fine-grained particle-containing Al-Sc alloy, Acta Mater. 53 (2005) 1097–1109.

The presence of the water vapour can affect oxidation in a number of different ways.
The scales consist of fine-grained oxide crystals, quite loosely packed.
Upon incorporation into the alumina scale Zr segregates to the oxide grain boundaries, which subsequently leads to formation of zirconia precipitates and pores [12,13].
The presence of the water vapour can affect oxidation in a number of different ways (depending upon the alloy and the oxidizing conditions).
On the Kanthal APMT small, globular grains in the external part of the oxide scale and large, columnar grains in the internal part of the scale are observed.

In the harvest time, cluster's length, coarse grain and shaft spike thick were measured via the tape.
In addition, cluster line number and seeds number of corn were determined.
Irrigation amounts significantly affected row grains and single spike weight.
Row grains in T5 and T6 were the best compared to other treatments.
Characteristics of steep cultivated land and the impact of the grain-for-green policy in China.

The measurements showed that the average size of the initial В2 austenite grains arising as a result of the above-mentioned heat treatment is 1.0–1.5 μm.
Already as small deviations as ±0.25 and ±0.50 at. % titanium and nickel decrease the average grain size B2 to 800 and 500 nm, respectively (Fig. 1).
It has been established that these phases were revealed upon the analysis of a whole number of SAED patterns.
The melt-spun ribbons subjected to additional annealing have a different grain structure and different phase composition.
Therefore, in contrast to the bulk crystallization, the development of such a mechanism, which is called primary crystallization and occurs with a change in the chemical composition, decelerates somewhat, but since the number of nuclei is increased, in the final account such crystallization is accompanied by an increase in the dispersity of the grain structure.

Results and Discussion Four cylindrical parts under numbers 1, 2, 3 and 4 were chosen as the objects of investigation, with a chromium coating of different thicknesses applied to their surface obtained at close technological modes.
The microstructure of the base metal, in addition to the HFC hardened layer, is perlite (dark) and ferrite (light) grains (Fig. 3a).
The structure of the base material is uniform, the grain size is 80 - 120 μm, which corresponds to 5 - 6 austenitic grain number.
The microstructure of the base metal (base) of sample 3 is a light ferrite mesh and pearlite grains.
The microstructure of the base represents a light ferrite grid and dark grains of lamellar perlite.

Fig. 5b Grain size map.
Table 2 Nickel grain size of different composites.
Fig. 6c Grain and phase boundaries, marker 5 µm.
In the corresponding grain boundary map (Fig. 6c), the transition from an increasing number of equiaxed tiny grains to large columnar grains is demonstrated by high-angle (black bold lines), low-angle (black thin lines) and twin (grey lines) boundaries of nickel grains.
The cumulative mass loss as well as the maximum erosion rate are appropriate as representative numbers for the comparison of cavitation tests under the same conditions.

In this case, the presence of a sufficient number of fine particles plays a decisive role in ensuring the mixture high connectivity and homogeneity.
As noted by many researchers in a number of works [15-17], when using the Linamix additive PCX a high plasticizing effect and cohesion of concrete mixtures are achieved with long-term preservation of the original properties.
The grain size composition of small aggregates is presented in table 4.
Evaluation of the water-reducing efficiency of the Linamix chemical modifier PCX in concrete mixtures on various cements showed a high sensitivity of the additive not only to the material and grain composition of the cements, but also to the grain size distribution of fine aggregates [19, 20].
Usepyan, Influence of stone crushing screening and mineral filler on the characteristics of fine-grained self-compacting concretes, Engineering Bulletin of the Don. 3 (2017).

However, grain size distribution of composite materials prepared by solid phase is uneven.
The results show that grain distribution of Z-AT samples prepared by coprecipitation method is more uniform, binding degree among grains is better.
The results show that grain distribution of Z-AT samples prepared by coprecipitation method is also more uniform, binding degree among grains is also better.
Grains and grain boundary of the complex phase materials will produce the tremendous stress, which lead toexist tiny cracks inside the grain and even grain boundary.
Moreover, the presence of a certain number of cracks in samples helps to improve the thermal shock resistance.