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Experimental Mg+2 wt.% Al alloy, having random texture with a grain size of (85 ± 10) µm was used for the experiments.
It is obvious that in tension the count rate peak is wider, which is a consequence of higher number of nucleated twins [3].
During tensile test, in grains having high Schmid-factor for extension twinning the number of nucleated twin variants is usually between 4 and 6 [8].
We assume that in the 1:1 mode there are more grains involved in the twinning process (c.f. higher AE activity).
· The number of nucleated twins is higher for uniaxial tension and 1:1 mode case

The 6082Zr grain size is much coarser (80 µm).
Multipass ECAP produces a strong refinement in grains size: after four passes via route Bc both the alloys exhibit similar average grain size (200 nm) (Fig. 1b and 1c).
Bands of different grain orientation are also present in the strained sample.
Fig. 7 shows the equivalent strain of 6082Zr and 6082ZrSc as a function of number of ECAP passes for the outer, the inner and the center mesh element at the starting process position.
Equivalent plastic strain of 6082Zr and 6082ZrSc as function of number of ECAP passes (top).

The compound fibres (Fig. 3a) exhibited rather flat and large fracture facets comparable with the mean grain size of 90 µm.
The crack growth was strongly affected by the microporosity as evidenced by a higher number of pores on fracture surfaces when compared with the cross-sectional porosity [2].
Occasionally, the cracks followed the pore clusters at grain boundaries to create intergranular facets, as seen in Fig. 4a).
Morphological patterns on the fracture surface with quasi-cleavage facets associated with river patterns at the grain boundary.
Coloured topology of semi-elliptical parts of fatigue fracture surfaces of selected compound and a porous filaments fractured at a nearly equal number of cycles is depicted in Fig. 7 (elevations red and valleys blue).

The size of magnetic grain is in nanometer scale, and each grain is in disordered direction.
However, reducing the magnetic grain can cause unstable data in storage and thermal fluctuation.
Where k is the number of data symbols being encoded, and n is the total number of code symbols in the encoded block.
However, the situation is improved if the number of errors is less than 10 symbols per block.
SER can be the most desirable result since we can verify entire sector instead of number of error bits.

With increasing pass number, the vacancy concentration gets more and more similar with all three routes.
The actual difference of three orders of magnitude in vacancy concentration roughly corresponds to the actual volume fractions of grain interiors to grain boundaries.
This paper should not end without mentioning that the high number of vacancies has important effects other than those to mechanical properties.
By this way, the number of dislocations and/or grain boundaries in the material is limited, and thus the macroscopic strength, too.
Symp.Ultrafine Grained Materials III, ed.

Many efforts have been made by a number of investigators to find out a retrogression and re-aging process (RRA) process that is eligible for enhancing the stress corrosion resistance of 7050 alloys without sacrifice its strength [4-5].
The precipitates in peak aged sample are very small and distribute continuously at grain boundary.
Retrogression and re-aging can make precipitate media and distribute discontinuously at grain boundary.
Therefore, the precipitate state (in matrix and grain boundary) of the RR-aged samples is suitable for passivation and reducing corrosion susceptibility during the SSRT process.
Incoherent and active GBPs accelerate the local corrosion initiation, since the severe heterogeneity of chemistry component in grain boundary region produce a number of micro galvanic cells.

Figure 2 shows relationship between applied nominal stress amplitude and number of cycles to failure for a smooth and a notched specimen of Ti-6Al-4V alloy under two different stress ratios of 0.1 and 0.5.
The critical nominal stress amplitudes as well as the number of cycles to failure at the kinking point are listed in Table 2.
Since the average grain size of the present Ti-6Al-4V alloy was 15μm, it was found that the plastic zone size of about 0.06mm corresponded to the size of about 4 grains for the present Ti-6Al-4V alloy.
The similar correspondence between the plastic zone size at the kinked point and the size of about 4 grains has been found in the 2024-T4 alloy with the same notch geometry.
(2) The kinking behavior occurred when the plastic zone size increased up to the size of about 4 grains for both the titanium alloy and the aluminum alloy

Small sample with finer initial grain size ~30 μm (as received) was selected so as to capture relative continuous regions and with larger grain numbers for a good statistical representation to analyze the texture evolution during single pass of ECAP.
Grains and twins were fragmented and elongated.
Due to material variation, such as initial texture and grain distribution topology, the shapes of the deformed grains will assume different inclinations [10].
The initial Cu has equiaxed grains with average grain size of ~30 μm and often twinned.
The corresponding SAD patterns reveal that a more uniform distribution of diffraction spots, indicating a large percentage of grains with high-angle grain boundaries.

Fig. 2 and 3 are inverse pole figure of grains at the center and near surface regions of pilgered tube.
As shown in Fig. 2 and 3, preferential distribution of the (001) and (100) planes along radial and longitudinal directions exist in a grain at the center region of the pilgered tube, whereas, the preferential distribution of the planes in a grain at the Fig. 1
One of interesting points in Fig. 2-4, grains at the center region of pilgered tube have relatively similar pole distribution to grains at the center region of the initial material, whereas grains near surface of pilgered tube have quietly different pole distribution to grains near surface of initial material.
It depends on stress-strain condition of each grain, which influences pole distribution during annealing.
Acknowledgements The authors would like to thank Korea Science and Engineering Foundation (KOSEF) though National Research Laboratory (NRL) Program, Neutron Beam Application Lab. and the Ministry of Science and Technology (MOST) of the Republic of Korea (Grant number M1060000024806J000024810) and Korea Nuclear Fuel Co for their valuable supports.

Currently, there is a large number of companies offering steels and alloys with increased wear resistance: Hardox [12, 13], Raex [14], TBL [14], Durostat and Brinar [14].
A large number of studies is devoted to increasing the wear resistance of these steels.
A small amount of fine carbide (Fe, Mn)3C is observed in austenite grains and at grain boundaries.
The size of austenite grains is about 80 - 100 µm.
The steel microstructure after pressure treatment and water quenching is heterogeneous over its entire volume (Fig. 2, a) In the center of the specimen, there is coarse-grained austenite with grain size of about 100 µm (Fig. 2, b).