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The dynamically recrystallized grains were mainly at prior grain boundaries, and had a grain size of about 2mm.
Figure 2) Misorientation profile across the dotted line shown in the EBSD map at slice number 38.
Relationship of dynamically recrystallized grains to the old grains.
The recrystallized grains formed a necklace at the prior grain boundaries.
An example is shown in figure 3, where at slice number 8 the grains A and B at first seem to be unrelated, however at slices 9 and 10 it can be clearly seen that grain B has a very close orientation and is linked to the old grain A.

Introduction Nanocrystalline materials consisting of nanometer-sized crystallites contain a large number of interfaces such as grain boundaries and triple junctions, and thus, a large volume fraction of atoms are associated with the intercrystalline region [1].
The average grain size increases drastically above 400°C.
The blue colored area indicates the <111>//ND grains and the red one does the <100>//ND grains.
Furthermore, the growth of the <111>//ND grains may be referred to as 'abnormal grain growth' in length scale, i.e.
Abnormal grain growth tends to occur when normal grain growth is suppressed by precipitate particles [7] and/or by solute atoms [8].

The grains misorientation angle was quantified by measuring the orientation of single cleavage facets with respect to its neighbours, hence a number of cleavage facets and their misorientation angle was measured.
For the normalized steel, the number of grains boundaries with misorientation angles between 3° and 10° was about 15%.
Low-angle boundaries, where the angle between the grains is low, may be regarded as arrays of dislocations, the number of dislocations involved in the boundary and the total energy of the boundary increases as the misorientation angle increases.
Furthermore, unlike to low-angle boundaries, where the boundary energy is related the misorientation angle, and thus to the number of dislocations involved in the boundary, the energy of high-angle boundary is rather independent of the misorientation angle.
Kim showed a distribution of misorientation angles where the large number of boundaries are into two ranges of misorientation angles; the ranges were below 10º and between 50º and 60º in a bainitic steel [16].

At the same time, grain and the second phase is not easy to grow, grain boundaries are also smaller.
During the artificial aging treatment, it producing a large number of dislocations and sub grain [8], the alloy in the second 120 ℃ aging treatment greatly increased the number of recrystallization nuclei, and thus grain refinement.
When the material is subjected to stress, first in the grain crystal defects in or along the crystallographic required energy minimum slip surface formation of dislocation, dislocation in grain continuously expand.
The first is the strengthening of grain.
After 480℃/80min + aging in 120℃/4h + cryogenic treatment + aging at 120℃/16h, on the microstructure of 7A04 aluminum alloy by recrystallization and refined the grain, thus, increasing the grain boundary area.

From matellographic analysis, grain refinement was observed obviously beneath the dimple.
Ji et al. [11] built micro-scale numerical simulation model of LPF based on material grain.
The morphology of the grains under the laser power density of 5.07GW/cm2 and the repeated shock number of 4 is shown in Fig. 8.
The average size of the refined grain is 6.26μm.
Compared with the grain size of 11.36μm which is far away from the dimple, the grains in the refined layer are refined by 44.89%.

Achieving Superplasticity in Fine-Grained Al-Mg-Sc Alloys Pedro H.R.
Superplasticity denotes the ability of a limited number of materials to achieve exceptionally high tensile elongations of at least 400%.
An analysis of published data for a large number of Al-Mg-Sc alloys shows that the results are mutually consistent and in reasonable agreement with the theoretical model for superplastic flow.
Langdon, Influence of scandium and zirconium on grain stability and superplastic ductilities in ultrafine-grained Al-Mg alloys, Acta Mater. 50 (2002) 553-564
Langdon, Twenty-five years of ultrafine-grained materials: Achieving exceptional properties through grain refinement, Acta Mater. 61 (2013) 7035-7059

According to the characteristic of the BSE image, B element with the smallest atomic number among Ag(47), Cu(29), Ti(22), B(2) gives off little back-scattered electron, hereby the B single is much more feeble and TiB2 particle appears darker than α phases in bright area (mainly Ag elements) and β phases in grey area (mainly Cu elements).
Many columnar compounds are formed on the surface of the brazed grains so that the grain edges are seriously destroyed, as shown in Fig.4(a).
The compounds look compact on the grain surface.
Under such circumstance, the molten filler spreads to the top of the grains so that all the grains are enwrapped by the filler layer.
The sharp edges of the grains are thus protected.

Many oblique strip grains appeared between equiaxed grains and fibrous tissue.
(a) Small grains, (b) Fibrous tissue during recrystallization process, (c) Fibrous tissue, (d) Long strip grains, (e) Coexistent structure of long strip grains and large equiaxed grains, (f) Large equiaxed grains.
Figure 4(a) shows that a large number of equiaxed grains have formed in outermost layer of specimen, and their sizes are very uniform.
Figure (f), only a large number of etching pits can be observed which distribute in surface of sample uniformly, and in fact the organization in this region should be larger equiaxed grains.
In the macro scale, plastic deformation is usually reflected as increasing of hardness, while in the micro scale there are a large number of dislocation and dislocation tangles.

An A3003 alloy was modified by Ti addition, grain refiner.
The finer grains were uniformly distributed in the modified A3003 alloy billet.
The grain refiner was added to the aluminum alloy for the modification of the A3003 alloy. 2.
In the simplest and dominant model, numerous potent heterogeneous nuclei (TiAl3) are dispersed in the melt, and a large number of these sites become active on cooling and nucleate the solid.
Thus TiAl3 particles during the solidification act as a grain refiner in aluminum alloys and the efficiency of grain refinement increase with increasing Ti contents in limited range (0~0.15) [4].

Introduction Nanocrystalline materials, which are structurally characterized by nanometer-sized grains with a large number of grain boundaries, have been found to exhibit many novel properties relative to their coarse-grained counterparts [1, 2].
The sample surface to be treated is impacted by a large number of flying balls over a short period of time.
Within initial coarse grains, multiple twins are formed and their density varies from grain to grain due to different crystallographic orientations of the grains.
Apparently, formation of these high-density nanoscale twins induces a large number of twin boundaries subdividing the original coarse grains into lamellar nanocrystallites with special crystallographic orientations.
The presence of a large number of twins and their intersections hinder dislocation activities, and more dislocations exist at twin boundaries across which small misorientations were induced.