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The amount of grain boundary of test steel Ⅱis smaller, which leads to lower grain boundary energy.
Because the solid solution of Cr in Fe reduces the stacking fault energy of the steel, a large number of low-energy intragranular interfaces are formed during the hot-deformation process.
At the same time, Cr segregation at grain boundaries could pin the grain boundary migration, which can hinder the forming of larger-angle grain boundaries.
Therefore, the addition of Cr in the test steel Ⅱ lead to the increasing of low-angle grain boundaries and sub-grain structure.
The addition of Cr leads to the increasing of low-angle grain boundaries and sub-grain structure, which is conducive to the improvement of corrosion resistance.

The researches made by the authors have aim at the obtaining of Ni-Ti materials with fine grain or ultrafine grain through powder metallurgy techniques, starting from ordinary metallic powders of Ti, Ni, Cu, with grain size less than 100 micrometers, and also using processing through severe plastic deformation (HPT-high pressure torsion).
In addition, we can avoid problems arising from casting defects due to segregation or the likelihood of excessive grain growth.
The objective of the research was to obtain a NiTi material with fine / extrafine grains starting with titanium powders, nickel and copper, with a particles less than 100 micrometers size, the techniques of powder metallurgy (P1 series) and, in addition, to processing by severe plastic deformation, HPT, (P2 series).
In the peripheral areas (a) it is distinguished a pored lace but in sample center (b) the material it is compact, with a very low numbers of small insulate pores of round shape.

Only grains consisting of at least six pixel were regarded for the analyzes, which results in a minimum detectable grain diameter of around 1.4 µm.
The separation between recrystallized grains and deformed grains was accomplished by the grain orientation spread since this method was proven the most reliable for nickel based alloy using EBSD [5].
Both parameters are positively correlated with the grain size.
Besides the different number and size of recrystallized grains it is obvious that the recrystallized grains are mostly located at former high angle boundaries and not in the interior of the grains.
The strong serrated grain boundaries of the initial grains confirm this assumption.

Increased carbon Chrom in HAZ sections allows for corrosion of grain limits.
Grain boundary corrosion occurs when the grain boundary area is affected by its deposits [3].
It shows that neither grain boundary corrosion nor crack appears in this material.
Based on Fig. 10, sample 3 with a variable pulse on-time variables 8 [μs], servo voltage 20 [V], wire-feed 5 [mm/min] is visible that a significant number of pore pores are produced.
The presence of Cr23C6 indicated the corrosion process happening in this grain boundary.

Comparing Figs. 9(a) and (b), it can be known that contours of abrasive grain are almost similar but the numbers of contour lines in this grain decreases.
It may display that attrition wear takes place in this abrasive grain.
Abrasive grains A in Figs. 11(a) and (b) are released.
That is, suspending ability of abrasive grains is weak just after dressing and then it can be considered that abrasive grains have a tendency to be released.
In this volume area, grain fractures tend to take place as shown in Figs. 11(c) and (d).

Silicon nitride is an interesting material for this application because bodies with high mechanical strength, achieved as a result of “in situ” anisotropic grain grown, can be obtained.
In fig. 2(c) are showed the fracture surface of the sample 30K/1800ºC/1h, where can be found some anisotropic grains in the ceramic matrix.
Rotoevaporation and freeze-drying methods improves the mechanical properties by a better particles packing because the powder was less agglomerated than the kiln-dried powder, what reduces the number of defects in the ceramic matrix.
When the sintering time was increased to 3 hours the phenomenon of “in situ” reinforcement, promoted by the anisotropic grain growth of silicon nitride become more evident.
Results of mechanical strength presented strong relation with de porosity and “in situ” reinforcement promoted by the anisotropic grains of silicon nitride.

In both images, the size of randomly selected grains is indicated.
In general, for thin-film optical applications it is desirable to have a columnar grain structure with a lateral grain size that is larger than the thickness of the thin film [13].
The size of randomly selected grains is indicated in the images.
The increase in carrier mobility after annealing can, at least partly, be attributed to the increase in grain size and reduced grain-boundary scattering [19,20].
The average grain size increases from ~70 nm for the as-grown film to ~600 nm for the annealed film.

An introduction to the structure of heat-resistant composition of single substituted orthophosphate of calcium (double superphosphate) in a number of 0.2% of the mass of cement allowed to increase the thermal firmness of structures to 20 heat exchanges (water, 800 ºС).
Additional stresses arise that cause a breakdown in the bond between the aggregate and the cement stone due to the fact that the hardened cement shrinks during dehydration and the aggregate grains expand.
Results Obtained in Experimental Studies Of the various types of concrete, the use of fine-grained concrete has increased most noticeably.
Fine-grained compositions are easily and efficiently modified using organic-mineral additives, providing materials with different complex properties.
The undoubted advantage of fine-grained structures is the use of cheap local sand, secondary material resources, which reduces the cost of concrete by 15-25% compared with traditional coarse-grained concrete.

Fig.1(c) shows grain refinement (5~10μm) of Al-17.5Si alloy surface due to superfast solidification with 108K/s [8].
But, the wear loss of 25 pulse-treated alloys significantly increases as compared to that of 15 pulse-treated samples, indicating decrease of wear resistance with further increase of pulse number.
Grain refinement of melted layer is achieved after HCPEB treatment.
Fine-grain strengthening is considered to be a contribution to wear resistance enhancement of HCPEB-treated alloys.
The main reasons are attributed to primary Si refining, solid solution and fine-grain strengthening.

Abrasive grains of mill-grinding tools fabricated by spraying method shed easily.
Tiny abrasive grains are coated on the rear face of the tool.
The larger the grit number is, the smaller the particle size is.
Larger abrasive grains shed more seriously, as seen in Fig.9.
Abrasive grains of micro mill-grinding tools fabricated by spraying method shed easily.