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The grains of AlN film had a worm-like shape.
When the number of layers (and cycles) increased, the (100) and (110) oriented grains weakened and the structure of film changed into (002) and (101) oriented.
Worm-like shape grains of nano-size were developed after one cycle.
The long axis of these grains is parallel to the sub- strate surface.
The grains become smaller and change to homogeneous (in dimensions) grains at higher number of cycles (2 and 4).

A commercially available hydroxyapatite (HA) was sintered for a number of sintering temperatures and times between 1150°C to 1350°C and 0 to 12 hours respectively.
However, sintering at 1350°C shows a large increase in the grain growth with grain sizes in the region of 20 µm after 12 hours.
As full density is reached after sintering at 1250°C for 1.5 hours, the driving force for sintering is transferred to the grain growth process shown by a slight increase in the grain growth rate and therefore the overall grain size.
Using the relationship (D-D0) = ktn, where D is the measured grain size after time t, D0 the average grain size after time t = 0 and n is the grain growth exponent, k, the rate constant, was calculated for each of the sintering temperatures as seen in Fig. 4.
The grain growth exponent (n) of 0.44 was used as the best fit value of the error.

Grain Boundary Diffusion and Grain Boundary Segregation in Metals and Alloys.
We name only a small number of the recent titles: I.Kaur, Y.Mishin, W.Gust “Fundamentals of Grain and Interphase Boundary Diffusion”[1], I.Kaur, W.Gust, I.Kozma “Handbook of Grain and Interphase Boundary Diffusion” [2], the review articles of Y.
Grain boundary self-diffusion 2.1 Fisher model.
Grain boundary heterodiffusion 3.1.
It was shown that the Fe-Fe coordination number is close to 1, which is much more than in a random solution.

Therefore, after two TC the microstructure was composed of fine grained reverted austenite and RA of large grain size.
IPF map depicting the progress of recrystallisation with increasing number of TC is shown in Figure 2.
Table I: Change in the % volume fraction of DIM with increasing number of TC.
Interestingly, no significant increase in the grain size and reduction in the fraction of low angle boundaries (LAB) were found by increasing the number of TC.
The persistence of LABs even after eight numbers of TC indicates incomplete or longer duration of recrystallisation.

This microstructure evolution is also be supported by the corresponding SAD pattern that changed from single crystal type to polycrystalline type with increasing pass number of CCDP substantiating grain refinement and increasing misorientation across the grain/subgrain boundaries, as evident from the TEM micrographs and SAD patterns in Fig. 3a-d for 1, 4, 8 and 16 passes of CCDP, respectively.
After that the grain size didn't decrease any further, but grain boundary misorientation increased steadily with the number of CCDP passes (see the SAD patterns in Fig. 3-4).
Fig. 5: Mean grain size along the longitudinal direction of both alloys as evaluated from the grain size distributions of 700-1000 grains for each sample.
The strain softening becomes more pronounced as the number of CCDP pass increases (Fig. 6a).
Fig. 8: Microstructure of Al-1.5Mn and Al5Zn-1.6Mg alloys after large number passes of CCDP.

A fine-grained 90W-7Ni-3Fe alloy with high tensile strength and elongation properties was obtained, in which the tungsten grain size was 8-12μm, the maximum tensile strength was 1050 MPa and the elongation was 30%.
Both Ryu and our earlier studies have demonstrated that a nearly full-dense W-Ni-Fe alloy with 3-5µm grain size can be obtained via solid phase sintering [5-6] , but this accelerates grain coalescence which is accompanied by decrease of the sintered density during liquid phase sintering [7-8] .
With adding 0.04wt% of Y2O3 in the alloy, the number of tungsten grain transgranular fracture increases (as shown in Fig.4(b)), and the matrix shows obvious ductile rupture characteristics, which appears to be a nest-like shape (as shown in Fig.4 (c)).
The optical micrographs of the alloys in Fig.4 show the tungsten grain size and its distribution.
When Y2O3 was added, smaller particle tungsten grain that reprecipitated from liquid phase were found, causing the contiguity of W-W to decrease.

China Keywords: Photostriction, PLZT ceramics, Anomalous photovoltaic effect, Grain size Abstract.
To control the grain sizes of the PLZT ceramics to the same, a simple grain growth model (see Eq. 1) were applied to determine the different sintering periods for the different compositions.
Fig. 4 Contour map of photovoltage in PLZT system as a function of the composition when the grain size is controlled.
Grain size control.
It has been reported that the photovoltage generated has an inversely proportion with the average grain size [5] (see Eq. 2) V0 = Φg l / lg (2) Since the grain size dependence was excluded, the results above are the intrinsic property in the PLZT system, The photovoltage generated in a single grain of the PLZT 3.44/52.73/47.27, therefore, is the largest, suggesting that the product of the number of impurity levels and the asymmetry of materials of this composition reaches the maximum [6].

refers to the total density of dislocations in coarse-grains and the nano-grain.
The back stress induced by dislocations accumulation can be simply expressed as (4) whereis number of dislocations that emit from the nano-crack tips.
As illustrated in Fig. 1, we only consider the number of dislocations emitted from the crack tip of NC copper when the angle is 70°.
can be get from (5) where is the maximum number of edge dislocations that can be emitted from the crack tip along one slip plane, it can be get from the Fig. 2.
The strength of the material decreases with increasing the grain size of the coarse grain.

The IGC-susceptibility was related to a nanoscale Cu-rich film along the grain boundaries, along with coarse Cu-containing precipitates at the grain boundaries.
These precipitates along with the Cu film along the grain boundary are believed to contribute to the cathodic activity as grain boundary attack proceeds.
The segregation of Cu at the grain boundaries, gives us reason to assume solute depletion adjacent to the boundaries, making this area anodic to grain bodies and grain boundaries.
The adjacent zone, which must be depleted in Cu, is active compared to the grain bodies and grain boundaries and is therefore susceptible to knife line IGC.
Upon further artificial ageing, the grain boundary precipitates grow in number and size as a result of further precipitation and disruption of the continuity of the Cu-rich grain boundary film.

High compressive tensions are generated below the grain.
The secondary chip formation takes place behind the grain.
This experimental set-up allows the analysis of the resulting scratch groove after a defined number of revolutions.
This procedure comprised the recording of SEM-pictures after a certain number of revolutions and at a selected position of the sample.
In Fig. 5 (a) the produced scratch groove on a high-strength concrete sample at three different numbers of revolutions n = 2, 10 and 20 rev is shown.