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This paper considers the oxidation of a number of nickel containing Fe based alloys of varying compositions, including stainless steel.
This makes the structure of the scale more complex as the number of phases present increases.
Although this Ni seems to be segregated to grain boundary regions, closer examination (Fig. 3) revealed that the Ni is located in regions adjacent to the grain boundaries.
It was found that, as expected, the internal oxide is situated at the high angle grain boundaries and not the twin boundaries, which are clearly visible within the grains shown in the IQ map.
Iron from the substrate below the nickel-enriched layer and in the area surrounding the grain boundary will diffuse outwards preferentially along grain boundaries where it will meet inwardly diffusing oxygen.

In terms of the average number of grains through the sheet thickness, r0 had 35, r10 had 12.5, and r20 had 24.
The biaxial limit strain of r0 was lower than would be expected on the basis of a simple relationship between the number of grains through the sheet thickness, as indicated by Wilson et al
Using this definition of the limit strain, the effect of the number of elements- representing grains- through the thickness and also of the degree of orientation clustering could be evaluated.
There is a clear effect of domain thickness; limit strains in both strain states increase as the number of "grains" through thickness increases.
Predicted in-plane limit strains (ε1*) as functions of number of grain through thickness, N, for CPFEM simulations with spatially uncorrelated orientations.

If the sample, of which the deformation strain is 2%, are taken to be observed, a large number of dislocations can be founded in the grain interior due to the occurred deformation(Fig. 1 (a)), and apparent dislocation networks can also be found in some regions(Fig. 1 (b)).
The trend of polygon is very obvious in the local area (Fig. 1 (e)), while in other regions, sub-grain boundaries began to dissociate, which is the start of sub-grain polymerization mechanism.
The arrow of the figure1(g) shows that after the sub-grain boundaries are completely dissociated, the sub-grain A and B that is merged, and it continues to grow up here by recrystallization.
It is shown from figure1 (h) that the dislocation density inside grains becomes high.
Acknowledgments The authors would like to acknowledge the financial support of the National Natural Science Foundation of China under granted number 50974063 and Jiangxi Provincial Education Department program under granted number GJJ09228.

Birmingham parameters were used to characterize the performances of grinding wheel, in items of grain density, grain shape and grain sharpness.
Density of abrasive grains.
The Birmingham parameter of Sds is the number of summits of a unit sampling area.
Its expression is: number of summits ( 1)( 1) Sds M N x y      (2) where M and N are the number of data points in x and y directions; Δx and Δy are the sampling interval in x and y directions.
With a smaller sampling interval, a larger number of peaks will be counted.

When a grain-boundary is exposed to a high, completely elastic mechanical stress σ, an embrittling species can penetrate it by grain-boundary diffusion.
On the other hand, if the crack tip iss surrounded by a high number of CSL grain boundaries, it should be possible to reduce the susceptibility to cracking by dynamic embrittlement [8,13].
As represented in the crack velocity vs. stress-intensity factor plot in Fig. 7b, crack propagation along a random high-angle grain ductile-fractured grain boundary 10µm boundary is by two orders of magnitude faster than along a special symmetrical Σ5 grain boundary.
Under the influence of a high elastic tensile stress acting normal to grain-boundary planes, an embrittling species can diffuse into the grain boundaries and lower the interfacial cohesion.
Small-angle grain boundaries or special grain boundaries with a high fraction of coincident lattice sites between the neighboring grains seem to exhibit a particularly low diffusivity of the embrittling element; i.e., they have a high resistance to dynamic embrittlement.

The varistor voltage increases with increasing number of ZnO grain boundaries between the electrodes.
Therefore, to fabricate varistors with low breakdown voltages, it is necessary to reduce the number of ZnO grain boundaries between the electrodes.
Adding only Ba to Bi-based ZnO varistors promotes grain growth, which enables large ZnO grains to be obtained [2].
This is because compounds containing both Ba and Mn do not form at grain boundaries between ZnO grains.
Excess Zn2+ ions at interstitial sites in ZnO grains have been reported to diffuse from inside the grains to the grain boundaries during annealing at approximately 700 °C [7].

Here, the grain morphology is the dominant one.
The second zone corresponds to columnar grain zone.
It corresponds to the zone of equiaxed grains.
· White spots (islands): observed near the grain boundaries and inside the grains.
Furthermore, a small number of tertiary dendrite arms are formed.

The samples were pressed for various numbers of passes up to a maximum of 24 corresponding to a maximum imposed strain of ~24.
The retention of a constant grain size with increasing numbers of passes is consistent with a model for grain refinement in ECAP [19].
The grains were essentially equiaxed after 4 or more passes although a slightly more uniform distribution of the Zn-rich and Al-rich phases was achieved after pressing through large numbers of passes.
N is number of ECAP passes.
Grain refinement in both alloys showed saturation after 4 passes of ECAP. 2.

The number of hydrogen atoms in the NDSR or HLSAD, per the dislocation length of b, can be described [2] as nH⊥ ≈ (CΣ - C) / ρ⊥ b2
In this connection, it ought to be emphasized that in a number of works, for instance [18,22,41, 42] some inadequate concept is used.
For a number of cases, this results [1] in reasonable values of ∆HB ≈ 40-20 kJ mol-1 and, correspondingly, reasonable values of K⊥ (increasing with reduction of CΣ).
Consideration of the Mössbauer and Diffusion Data on CLNS of Fe at Grain Boundaries in Al.
Numerous surface nodules, made of virtually pure nickel, were visible within the grains.

The numbers 0~8 in the figures correspond to each other, and refers to the different deformation stages.
The numbers correspond to those in Fig. 4.
Numbers 0-4 correspond to those in Fig. 4.
� � Matrix Journal Title and Volume Number (to be inserted by the publisher) 5 473K, 10-3s-1.
Besides the matrix, two DRX grains were observed, grains A and B.