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From a coarse-grained material state, in the absence of recovery/ recrystallization and grain growth or when work hardening prevails over recovery and recrystallization, with increasing deformation the grains are refined and the grain size decreases to a few hundred nanometers before saturation is reached [3].
For given straining conditions, the grain refinement reaches saturation at some stage and the grain size approaches a stationary value.
At the large strains corresponding to this condition of saturation (probably produced locally at rather high strain rates), we believe that dislocation generation in large numbers at a rapid rate facilitates the formation and growth of the micro-cracks to a size beyond the critical size needed for crack growth and failure.
Then, the grain size would be clearly larger than the theoretical limiting grain size.
Then, the final grain size obtainable will decrease.

The new grain nucleation firstly appeared at the protruding parts of grain boundaries.
Rolled at 850˚C, there was an increase in the number of grain boundaries while the deformation bands turned to be shorter and thinner.
In other words, with the rolling temperature decreasing, number of grain boundaries would increase and more uneven deformation bands would be got.
As showed in Fig.9, a large number of deformation bands could be investigated in cold rolled sheets.
(3) The number of precipitates decreased with the increase of finish rolling temperature.

It was found that post heat treatment could reduce the number of pores existed in the aluminum coating.
The resulted Al spray coating exhibited large defects including number of voids and pores due to incomplete inter-splat contact or numbers of un-melted particles, which is consistent with the results of Gao's report [5].
Thus, diffusion in Mg-Al system appeared to occur along the grain boundary The grain boundary diffusion is a complicated process.
Heat treatment could reduce the number of pores in the Al spray coatings. 3.
Grain boundary diffusion of atoms occurred in various engineering materials at elevated temperatures.

First part of description defines the machining method for surface (Bcbn-grinding, grain boron nitride, Bsg – grinding, grain SG, Ssk – turning, sintered carbide), specification next to dash behind pause defines the machining of notch (S-turning, B – grinding) The surface grounded by SG grain with grounded notch by CBN (cubic boron nitride) approves the longest durability in occurrence of ground surface with ground notch.
The surfaces formed with high quality show the longest durability from large number of measurements (Fig.11).
In case of manufacturing of design notch the ground notch made by CBN grains has the longest durability.
The influence of cuting speed does not become surprisingly evident with the CBN grains utilisation.
We can confirm here correctness of CBN grain application with grinding of design notches in production.

But among them, vertical centrifugal casting technology turns more and more into a fruitful method for its low production cost in producing a great number of special castings [2].
The casting loaded on a vertical centrifugal unit of the furnace has been revolved prior to the casting experiment in an anti-clockwise direction with rotation number from 0 rpm to 280rpm.
The microstructures of castings produced at 160rpm and 280rpm are all equiaxed grains, furthermore the grain sizes at the sharp corner of the wedge casting are finer for the bigger cooling rates at these parts.
The grain size changes greatly with different wall thickness of the casting.
Conclusions (1) The crystals near the outer surface of the wedge casting produced at the gravity field are columnar grains, while the grains produced at centrifugal field are all equiaxed grains.

Electrochemical corrosion behavior of Cu-20Fe-12Cr alloys with the different grain size in solutions containing chloride ions Zhongqiu Cao, Rong Xue, Jing Bian, and Yajun Fu College of Chemistry and Life Science, Shenyang Normal University, Huanghe Northern Street 253, Shenyang, Liaoning Province, China Email: caozhongqiu6508@sina.com Keywords: Fe-Cu-Cr alloy; grain size; electrochemical corrosion Abstract.
The corrosion rates of MACu-20Fe-12Cr alloy become faster than those of PMCu-20Fe-12Cr alloy because the reduction in the grain size of MACu-20Fe-12Cr alloy produces large concentrations of grain boundaries.
MA Cu-20Fe-12Cr alloy has more homogeneous microstructure and is able to produce large concentrations of grain boundaries in the course of reduction in grain size by mechanically alloying.
Atom in grain boundaries is arranged irregularly and its lattice distortional energy increases, grain boundaries have trend to decrease their energy automatically.
(3) The corrosion rates of MACu-20Fe-12Cr alloy become faster than that of PMCu-20Fe-12Cr alloy because the reduction in the grain size of MACu-20Fe-12Cr alloy produces large concentrations of grain boundaries and increases the number of reactive atoms in alloy surface.

The Ti-V-N steel has the lowest mean prior austenite grain size, where the prior austenite grains are distributed in bands of coarse and fine grains.
Single phase cuboidal (Ti,V)(C,N) particles were observed in all four steels, but in much greater numbers in the Ti-treated steel.
Nevertheless, the Cr-V-N steel, has a large number of individual and fine (Ti,V)(C,N) particles.
Histograms showing the number density of (a) (Ti,V)(C,N)- and (b) Mn-Al-(Ca) silicate-containing single or multi-phase inclusions.
V-N 50 and 25 exhibited similar inclusion populations, however, Cr-V-N presented a high inclusion number density of (Ti,V)(C,N)-bearing inclusions (Fig. 2).

To ensure a micro hole is drilled within a grain or on the boundary of grains, the diameter of an electrode should be less than the average size of grains.
The total number of micro holes drilled is 107.
In this study, the number of micro holes drilled within the grain is 56 and 51 on the boundary.
During the formation of a grain in alloy, a particle with the highest melting temperature solidifies firstly, forming a nucleus of grain.
Fig. 7 shows the distribution of discharge gaps of machining within a grain and on the boundary of grains.

In the 'ALAMEL' model [5], grains do not deform homogeneously.
Grains are divided into domains, and those domains are assumed to deform homogeneously.
Linear stacking of N number of homogeneously deforming domains is assumed to repeat periodically.
Fig. 2: (a) Macroscopic stress-strain response and (b) evolution of the average number of active slip systems, ⟨Sact⟩, of an idealized two-dimensional polycrystal when subjected to tension.N domains, so that MN = ng.
Fig. 2(b) shows the evolution of average number of active slip-systems for various stack size.

Evidently, the average NKLN grain size grows up gradually when temperature increasing.
NKLN powders annealed at 600°C show outstanding combination property, and the average grain size is the smallest.
Fig.4 SAED image of a typical NKLN particle Grain size and lattice constants of NKLN powders.
(1) (2) (3) Table. 1 Grain size and lattice constants of NKLN powders Calcined temperature/°C a=c/nm b / nm β/° Grain size/nm 600 0.4034 0.3976 90.5212 40.78 650 0.3981 0.3974 89.5925 50.56 700 0.3978 0.3963 90.2614 65.52 Table 1 showed the grain size and lattice constants of NKLN powders.
NKLN powders annealed at 600°C distributed uniformly, the mean grain size was 40.78nm.