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Nearly pore-free microstructure (99.8%) and narrow grain size distribution (4-10 µm) with an average grain size of 7 µm was obtained for the sample sintered in the vacuum atmosphere, while both inner and inter pores with abnormal grain growth, wider grain size distribution (9-27 µm) with the average grain size of 12 µm were detected in air atmosphere.
This causes abnormal grain growth and trapping of pores inner and inter of the grain.
As the sintering temperature increases, the number of the pores decreases (Fig. 6 and 7) and the relative density and grain size increases (Fig. 8 and 9).
At temperature higher than 1590 ˚C, when the advanced stage of sintering occurs, the difference between the number of residual pores, relative densities, and grain sizes are observed for the specimens sintered under air and vacuum atmospheres.
However, both inner and inter pores with abnormal grain growth, wider grain size distribution (9-27 µm) with average grain size of 12 µm were detected in the air atmosphere sample.

Bending angle increased as grain size increased and it jumped up when grain size exceeded the foil thickness and then became constant.
Laser device Q-Switch pulsed YVO4 Wave length [nm] 1064 Frequency [kHz] 200 Laser power [W] 2-14 Laser scanning velocity [mm/s] 10 Scanning number 1 Forming atmosphere Ar Next, effect of grain size on bending angle was investigated.
Effect of Grain Size.
Effect of grain size on bending angle is plotted in Fig. 7.
(2) As grain size became larger, bending angle also increased when grain size was smaller than the thickness of foil.

This is because the formation of grain is the process of nucleation and growth, during which a large number of intensive microcrystalline grain region are formed.
Furthermore, large amounts of impurities and grain boundaries in the intensive microcrystalline regions inevitably cause a large number of dislocations.
Hidalgo P and his coworkers pointed out that the metal impurities near grain boundary spread to the grain boundary under heat treatment at a certain temperature.
This means that the grain boundary has the ability to adsorb and precipitate metal impurities, which is the so-called “grain boundary gettering” [7].
The concentrations of a large number of metal impurities could significantly reduce the minority carrier lifetime the phosphorus gettering silicon wafer.

This suggests the occurrence of grain boundary sliding, probably with the help of tiny recrystallized grains existed in the vicinity around grain boundaries.
However, the macroscopic deformation must be impossible to occur just by the grain boundary sliding, because of the large grain size of the plate-like LPSO-phases.
The annealing of specimen at 400 ˚C for 168 h effectively coarsened the tiny recrystallized grains in the vicinity of the grain boundaries as shown in Fig. 3.
In this evaluation, the average length of long-axis of plate-like LPSO-phase grains was estimated as a grain size d.
The equation indicates that the decrease of orientation factor (Taylor factor) m reduces the k-value, which is brought about by the increase of the number of slip systems [7].

Ferrite separates out at both grain boundaries and inside the grains.
After hot-forging and air-cooling, the grain fineness number can reach level 7-9.
The ferrite in small blocks effectively divides up the austenite grains, reducing the grain size.
Tab.2 The HRC of developed steel I09-1, I09-2 after hot forging and air-cooling Steel Grade I09-1 I09-2 Heat Number 1 3 1 2 6 HRC 28.7 26.7 30.8 32.6 33.
The grain fineness number after hot-forging can reach level 7 to 9

However, the dimension of these notches is in the same order as the grain size.
The average size of the grains is approximately 30 µm.
The notch depth developed through the micro-milling process is smaller than the grain size.
The ultimate number of cycles was 107.
The numbers of run-out specimens per state are given in Fig. 4.

Unfolding grain size to 3D 4.1.
It must be noticed that the 3D connexity number NV, which is the number of particles for a phase is constituted by grains only when grains are sufficiently regular (isomorphic to spheres, i.e. with neither holes nor torus-like parts), cannot be directly measured on 2D images and that the 2D connexity number corresponds to a 3D curvature measurement, and not to a 3D number of objects.
Similar works were conducted on particle mixtures on the basis of the variance of 2D particles number [89].
An example is connectivity, also known as coordination number.
In practice, a limited number of measurements are available and needed.

The three IF steels are numbered 1#, 2#, and 3# in order of finishing rolling temperature from high to low.
The grain size of 3# is relatively small, with an average grain diameter of 35 μm, and the grain size is elongated along the rolling direction.
After annealing, the number of red and green grains decreased, while the number of blue grains increased significantly, indicating that γ-fiber formed strongly after annealing, with weak α-fiber and {110} texture.
Fig. 4 The proportion of blue grain area.
Therefore, {100}-oriented recrystallized grains are very few, and {111}-oriented grains dominate in the recrystallized grains [9, 10].

Zn grain boundary diffusivity P = s δ Db (s - segregation factor, δ - grain boundary width and Db - diffusion coefficient in grain boundary) was also determined and it was found that it obeys the Arrhenius law P = 7.2 × 10 -15 × exp (-46 kJ mol-1 /RT) m3 s-1.
The final mean grain size is listed in Table 1.
This is, most likely, caused by the partial (grain boundary) pre-melting.
Grain boundary diffusivity shows no significant dependence on Al concentration.
Acknowledgements The work was supported by the Czech Science Foundation - contract number 106/05/2115 and by the Academy of Sciences of the Czech Republic - number of the project AV0Z20410507.

A number of references [3-8] have reported the forming condition of {111} texture in IF steels, but few of them have paid attention to the difference in formation for {111}<112> and {111}<110> texture.
The microstructure of grains belong to {111}<112> component contains large number of subgrains, which integrate, coarsen and further form recrystallization nuclei with annealing time.
Secondly, interstitial carbon and Fe3C concentrate around grain boundary in low-carbon steel, which results in a higher ratio of hardness between grain boundary and inner grain.
Consequently, low fraction {111}<110> grains become dominant by consuming {111}<112> grains.
(2) Newborn grains with {111}<110> orientation are formed by mean of preferred nucleation during recrystallization on the boundaries between {112}<110> and {111}<112> grains; while {111}<112> grains nucleates within deformed grains with the same orientation through subgrain coalescence.