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The dislocation structures are heterogeneous because each grain in polycrystalline metals has the different orientation and heterogeneous defect field.
Experimental Results Figure 1 shows the relationship between the maximum peak stresses (normalized with the maximum peak stresses at the 1 st cycle) during tension-compression cyclic loading under the strain amplitudes of 0.25, 0.75 and 1.0% at the strain rate of 0.01%/sec and the number of cycles.
In the present study, we observe four different grains in each specimen and discuss the average structure.
The number of black pixels in the each binary image is counted and the proportions of black pixels in the each image are calculated.
(a) Original (b) Normalized image (c) Binary image Fig.3 Procedure of making binary image Table 1 The proportion of black pixels in each image Strain amplitude Grain A Grain B Grain C Grain D (Annealed) 3.92% 1.45% 7.36% 1.55% 0.25% 33.8% 13.7% 42.5% 11.6% 0.75% 37.8% 44.8% 56.3% 33.2% 1.00% 27.1% 44.4% 35.4% 43.7% Table 2 Arithmetic mean and variance of the black pixel proportions in each experimental condition Strain amplitude Arithmetic mean Variance (Annealed) 3.57% 7.69 0.25% 25.4% 230.1 0.75% 43.0% 101.1 1.00% 37.7% 66.2 Figures 4 and 5 represent the examples of generated images from the TEM images of the specimens cyclically deformed with the strain amplitudes of 0.25% and 0.75%, respectively.

To facilitate the following presentation, the alloy numbers is shown in Tab.2.
Tab.2 Alloy Number No.
The bonding force of Fe and Cu at the grain boundary is very weak in this structure and the Cu layer could be teared and flaked off from ferrite grain easily which is the reason for the weak impact toughness of Fe-Cu alloy[3]. 2.3 Analysis of hardness and impact toughness What is shown in Fig.6 and Fig.7 are the comparison of hardness and impact toughness before and after annealing respectively.
The reason of change above is that, the casting alloy is with original coarse grains and high internal stress, its grains are refined after annealing treatment.The mechanical properties are improved consequently[5]. 2.4 Analysis of electromagnetic properties The result of B-H curve test and resistivity test are shown in Fig.8 and Fig.9 respectively.
[3] Yuzen　Cheng，Gencan Yang, etc，Research on Grain Refinement Mechanism in Under Cooled Alloy.ACTA METALLURGICA SINICA703-707(2006) [4] Zhao Jun.High-temperature alloy machining.Solutions.136-137.(2010) [5] E Ploeckinger.

Both grains and colonies became finer as the location changed from the tip of the extruded bar to the back end.
In addition, a small number of pores (small near-circular shaped pores that are present inside a grain and larger lenticular pores present at the grain boundaries) can also be observed.
Additionally, a much finer continuous α layer surrounding the prior β grains can be observed.
A typical example of a non-uniform grain morphology near the tip of the bar can be seen in Figure 7 (a), where large, irregular, columnar grains are evident.
The β grains near the tip of the extruded bars have a typical size of about 140 μm.

The fracture toughness of steels will decrease with the rise of grain size or decrease of plastic performances [2].
The relevant qualitative research shows that α laths thickness and width of α lath at grain boundary are one of the most important microstructure parameters controlling the fracture toughness of TC21.
The relevant research shows that crack orientation would change when the crack propagates α phase at grain boundary.
When crack crosses the grain boundary, the amount of crack will also increase.
Acknowledgments The great supports from The Weaponry Equipment Pre-Research Foundation of The PLA General Armament Department (award number ###120001) are gratefully acknowledged.

However, most of transparent glass-ceramics only contains nanoscale size grains, the small grains size and low volume content of grains in glass-ceramics cannot improve the capacity of resistance to abrasion significantly.
By controlled crystallization process, the transparent glass-ceramic with large grains was obtained from the matrix glass.
A large number of strong diffraction peaks appear in this figure, indicating much crystalline formation; and the bread-like peak around 30° suggests the residual glass phase.
In present work, the chemical composition of glass and grain is the same, so the main differences lie in the scattering of the grains.
This is not accord with the grain size in the present work.

This grain structure is largely influenced by the thermal cycles the material undergoes during the process [7].
The grain structure determines isotropic mechanical properties of the part [7].
The first layer of WAAM components is initially deposited onto a base plate, where the grains tend to grow epitaxially, adopting the crystallographic orientation of the grains present in the base plate itself [13].
The changes of hardness may therefore be related to grain boundary hardening, that is an increasing number of grain boundaries clearly revealing higher hardness as the bulk of the material as a function of location.
Also, in epitaxial microstructures more grains per cross section are located perpendicular to the grain growth direction than in lateral direction leading to increased hardness perpendicular to the growth direction.

., grains, are embedded in an a-Si:H matrix), which were grown by plasma enhanced chemical vapor deposition (PECVD).
The fitted results are given in Fig. 2, indicating that the average grain size decreases with increasing CB.
Therefore, the a-Si:H surfaces of the grains contribute positively to the PL intensity, as implied by the correlation between bg and I0.
Since the PL peak energy is mainly determined by the grain size within the framework of QCE, the difference in the variation of grain size caused by boron doping is due to the difference between the two growth methods, i.e., the rf cosputtering [3] and the chemical vapor deposition (CVD).
In the rf cosputtering method, the grain size is controlled by changing the number of Si chips or the annealing temperature, and is almost independent of boron doping [3].

GB = Granular type bainite formed at austenite grain boundaries.
AF = acicular ferrite, i.e. bainite nucleated in austenite grain interiors.
Note that only solute Ti is considered, since precipitates were generally large (≥100 nm) and few in number i.e. were considered ineffective in inhibiting boundary movement [3]. 1) By analogy with Nb, solute Ti may delay the austenite to ferrite transformation by segregation of solute Ti to austenite grain boundaries.
Finally, the experimental observation of acicular ferrite in the Ti steel also indicates a reduction in austenite grain boundary energy, since nucleation is shifted to grain interiors. 2) By analogy with Cr and Mo, the nucleation of ferrite and the mobility of the austenite/ferrite grain boundary could be reduced by coherent Ti-C clusters.
Faulkner, Non-equilibrium grain-boundary segregation in austenitic alloys, J.

Pulse frequency fP It is the number of pulses per seconds.
The grain growth at different zones is shown in Fig 3.
Grain size frequency distribution of Fig. 14.
Grain size frequency distribution of PCTIG, CCTIG, (*grain size in μm) very fine grains (20μm) Conclusion In this study, the effect of pulsed current welding technique on mechanical behavior of welded AA6070 aluminum alloy has been reported.
Current pulsing leads to relatively finer grain structure References [1] V.

The grain size is biggest crystallized at 850°C for 2min by RTP.
The grain size is biggest crystallized at 850 oC for 2 min from XRD, an average grain size of 30 nm or so is obtained.
The experiment showed there existed discrete quantum states in the connection between the grain size and the temperature as the experiment.
The transitions between quantum states with different quantum numbers should forced by the certain energies corresponding to the proper temperatures and lead to different character of thin films.
Conclusion Amorphous prepared by PECVD on silex glass annealed by rapid annealing method, it is found that there existed the better the average grain size at proper annealing temperature.