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The number of the SPPs of each alloy was more than 15 for EDS analysis.
In comparison with the tubes final annealed at 480 ℃, the number of dislocations in the grains annealed at 510 ℃ was reduced, and the grains began to transform from the fiber structure during rolling to the equiaxed recrystallized structure, but since the recrystallization was not sufficient, elongated grains along the rolling direction were remained.
With the increase of the final annealing temperature, the number of low-angle grain boundaries decreased.
(c) (b) (a) Fig. 2 Grain boundary diagram of SZA-6 alloy cladding tubes (a) Final annealed at 480℃, (b) Final annealed at 510℃, (c) Final annealed at 560℃ (b) TEM analysis showed that after final annealing at 480℃, the SZA-6 alloy cladding tube contained a large number of dislocation lines, dislocation cells, sub-grains, and deformed grains, showing the appearance of unstressed state of grain morphology (Fig. 3a).
With the increase of corrosion weight gain, the number of holes or “steps” existing between the columnar crystals increased.

The heat treatments resulted in the formation of two phase (austenite-ferrite) ultrafine grained microstructures with average grain sizes of 0.9 to 1.2 µm, depending on the annealing temperature.
The use of medium manganese steels with a good formability will allow to reduce the number of components of the car, as well as to realize geometrically more complex parts, which also affect safety and environmental conditions.
The grain refinement leading to ultrafine grained microstructure can significantly increase the yield strength while ductility remains at a high level [9].
The cold rolled microstructure is mostly represented by austenitic structure with elongated grains along the rolling direction with average grain size of 1.7 µm.
The largest transverse direction of austenitic grains is about 10 µm.

The number of newly generated ultrafine grains increased with the strain; however, the average sizes were found to be independent of strain.
The grain size, `d`, was found to depend on Z parameter.
Grain boundaries that are clearly etched are only initial ferrite grain boundaries.
Along the initial ferrite grain boundaries as indicated by arrows, equiaxed grains having a size of less than 1µm surrounded by clear grain boundaries were observed.
However, equiaxed grains having a size of less than 1µm surrounded by high angle boundaries were generated along the initial ferrite grain boundaries, though small in number.

A number of fabrication methods involve severe plastic deformation, SPD, and involve refinement of the coarse-grained structures to grain sizes on a nanometre scale.
Among other factors, the effect of grain refinement down to nanometres has been examined in a number of metals and alloys [1-5].
A number of them involve severe plastic deformation, SPD, and consist in transformation of the coarse grained structures to grain sizes in a nanometre range via the accumulation, rearrangement/annihilation of the crystal lattice defects, primarily dislocations, and formation of new grain boundaries with misorientations increasing with applied strain [8].
It can be easily demonstrated that vastly different grain structures may have the same average grain size.
Figure 3 shows yield strengths of 7475 aluminium alloy strengthened by (a) precipitates (grain size of 70µm); (b) grain boundaries (grain size of 70 nm) and (c) by their combined effect (grain size of 70nm + precipitates).

It should be note that under conditions of conducted creep tests, material deformation caused by volume diffusion (Nabarro-Herring model) and diffusion along the grain boundaries (Coble model) may occur concurrently, and contribution of each of these processes to the deformation depends on temperature, stress, grain size, and structure of grain boundaries.
HT means heat treatment procedure Designation of heat and specimen Evaluation of the structure of superalloy Carbide content in surface area AA Morphological parameters of macrostructure 1 AA = 2.12% N = 45 - number of grains A = 0.57 mm2 - mean surface area of the grain 2 AA = 1.45% N = 7 - number of grains A = 3.55 mm2 - mean surface area of the grain 1 after HT AA = 1.97% N = 24 - number of grains A = 1.1 mm2 - mean surface area of the grain 2 after HT AA = 1.90% N = 10 - number of grains A = 2.7 mm2 - mean surface area of the grain Examination of nickel superalloy macro-structure demonstrated that the use of only bulk modification in casting experiment (blue filter - heat 2) result in a coarse-grained structure.
Analysis of creep tests results concerning the casts in their initial state (specimen no. 1 and 2) shows that coarse-grain superalloy is 27% than the fine-grain superalloy.
This influence is well described by the implemented parameter AA/N, (ratio of carbide content in surface area and the number of grains in a specimen, Table 2).
Creep resistance vs. selected morphological parameters of structure MAR-247 nickel superalloy Heat and specimen designation Creep resistance tz [h] Rate of steady-state creep Vu [s-1] Carbide content in surface area AA [%] Number of grains on specimen section N Ratio of carbide content in surface area and number of grains AA/N [%] 1 250.3 2.5 x 10-8 2.12 45 0.047 2 317.4 2.2 x 10-8 1.45 7 0.21 1 after HT 292.9 1.66 x 10-8 1.97 24 0.08 2 after HT 352.4 1.06 x 10-8 1.91 10 0.19 Conclusions Analysis of characteristic curves of creep for MAR-247 superalloy indicates that diffusion creep process on the grain boundaries determinates their resistance in the conducted creep tests.

Fatigue Behaviour in Fine Grained Aluminium Alloys L.J.
A fine, predominantly equiaxed grain structure withtypical grain widths of 3-5µm was seen.
A moderate grain size of ~5-20µm was seen (equivalent to the through-thickness grain dimensions in conventional DC cast plate and sheet products) with a <101> fibre texture being identified. 5091 is an Al-Mg-Li mechanically alloyed material [6] offering an ultra-fine-grained microstructure, with relatively equi-axed grains of less than 1µm size, stabilized by dispersions of 20-50 nm Al2O3 and Al4C.
A number of rogue 2-50µm grains were also seen however, up to ~ 25% of the material bulk [7].
In the first instance it is evident that growth rates do not scale simply with grain dimensions, as SC2 has the coarsest grain size amongst the present fine-grained Al alloys.

Most the grains present rosette-like and globular-like, there hardly being the grains with dendritic-like.
As the addition of lanthanum increases to 0.8%, more primary grain presents the rosette-like, and the grain with particle-like is decreased.
It is seen from the Fig.3 that there are strip-like or needle-like bright areas at the grain boundaries, which should be the enriching area of La theoretically, because the atomic number of La is biggest during the elements (such as Al, Si, Mg, La) contained in the alloy used in this test.
Moreover, lanthanum is a surface active element to reduce the interface tension of liquid alloy and to decrease the nucleation power of the grain, in which the critical nucleus radius decreases and the formation of nucleus is easy so that a great number of nuclei is produced in the melt to fine the microstructure.
Therefore, the latent heat released from the growth of dendrite raises the temperature at the linking section of arm of the dendritie to impel the dendrite locally to be neck shrunk and fused, thus the more crystallizing nuclei can be produced in the melt. 2) the eutectic reaction in Al-La alloy preferentially happens at the temperature higher than the liquidus temperature in A356 alloy, so that the α-Al grains crystallized from the eutectic reaction can provides the effective nuclei for formation of primary grain in A356 alloy. 3) La is a surface active element to reduce the interface tension of liquid alloy and to decrease the nucleation power of the grain, in which the critical nucleus radius decreases and the formation of nucleus is easy so that a great number of nuclei is produced in the melt to fine the as-cast microstructure.

Grain Distribution.
Through the investigation and dimension measurement to different size of micro grinding tool, the distribution of CBN grains on the surface of the substrate could be accomplished and it could be described by G0 which stands for number of grains within 1mm2 of square on surface of the substrate.
Number of abrasive particle on the surface of micro grinding tools Particle size Grit size（μm） G0(Particle number in 1mm2) F800 22~25 700~1000 F1200 4~6 7000~8000 F3000 2~3 12000~14000 Surface Topography Analysis.
From the result it is concluded that large number of grains could turn to low Ra, the F3000# particle size reach a roughness of 0.086μm.
A novel micro shaft grinding tool is fabricated by cold sprayed with CBN grains, G0 which stands for number of grains within 1mm2 of square on surface of the substrate is discussed in this study, it is found that the value of G0 only depends on the particle size which is verified in the investigation and the G0 to different particle size is showed in Table.2.The manufacturing is carried out on a micro desktop machine developed by NEU.

Stability of the results with respect to numerical parameters The influence of the number of grains and number of FEs per grain have been extensively studied using the simplest microstructure (Fig. 2 a).
The mean grain stress and plastic strain distributions depend only slightly on the number of grains provided they are higher than a few hundred (bulk grain or surface grain distributions).
In the following, the predicted curves or distributions computed by different approaches (mean-field versus full-field computations, microstructures of increasing complexity) are always compared for the same number of grains, FEs par grains if required and remote plastic strain.
Prediction of the distributions of the numbers of cycles to microcrack initiation The number of cycles to microcrack initiation, Ni, is computed for each grain.
Fig. 7 Computed distributions of mean grain number of cycles to microcrack initiation (see the criterion used in [11,18]).

Student 7 aaleksavdovin@yandex.ru, bgyakov@istu.ru, ca3zorin@mail.ru, disf@istu.ru Keywords: crumb rubber, asbestos-cement wastes, fine-grained concrete, modifying admixtures.
Using crumb rubber positively affects shock load bearing and contributes to resistance to a larger number of freeze-thaw cycles compared to conventional concrete.
Fig. 1, b shows that the mechanically activated crumb has better adhesion to the cement matrix and increases the density of the fine-grained concrete structure.
Additionally, asbestos-cement particles are a reinforcing component that helps compact the structure of the cement matrix of fine-grained concrete.
All these factors contribute to the compaction of the matrix structure, the reduction in the number and size of pores.