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The cyclic character of nucleation and growth of new grains during deformation results in a dynamically constant average grain size.
The nuclei of new grains appear as a result of local migration of original and/or strain-induced grain boundaries.
The numbers indicate the boundary misorientations in degrees.
The new fine grains evolved under warm working, therefore, are essentially the strain-induced largely misoriented (sub)grains.
Many annealing twins in new fine grains in Fig. 5a indicate the grain boundary migration.

All results, including grain size, texture, and grain boundary characteristics, were based on the analysis of no less than 4000 different grains.
During recrystallization and grain growth, the magnetic field creates an additional driving force for grain boundary migration between adjacent grains.
In addition, grains with higher susceptibility grow at the expense of other grains during magnetic annealing.
The results of the current study are in accordance with previous reports by Zhang et al. [15] and Harada et al. [16], who explained that annealing samples magnetically produced fewer low-angle misorientation boundaries as an effect of reduction in the number of dislocations.
(3) Pulse magnetic annealing can accelerate dislocation motion and decrease dislocation pile-up, thus reducing the number of low-angle grain boundaries due to repeated magnetostriction induced by application of a pulsed magnetic field.

The EBSD data of samples showed that normalization can half the grain size after primary recrystallization, raise the percentage content of favored grain boundaries and high-angle grain boundaries, increase the content of Goss orientation grains by 5 times.
Its superior performance attracted a large number of research scholars.
Analysis showed that the grain size in the {111} <11 > orientation and Gaussian grain matched the orientation relationship of high mobility grain boundary.
CSL Grain Boundary Analysis.
Data in Table 4 show two-phase normalization increased the content of ∑9 grain boundary particularly which favored Gaussian grain growth: it also favored growth of the high-energy grain boundary.

In situ tensile testing of ultra fine grained Pd and Pd-Ag alloys K.
This latter approach was used in our group to improve the strain hardening ability in a number of Pd-Ag alloys processed by high pressure torsion (HPT).
Results and discussion Grain scale analysis.
To further explore the problem, the in situ tensile testing was carried out for HPT-processed Pd and a number of Pd-Ag alloys to observe their deformation behaviour.
Fecht: Grain refinement and deformation behavior of ultra fine grained Pd and Pd-Ag alloys produced by HPT.

High-angle grain boundaries increase in number with increasing the amount of cold-work.
Results and Discussion Grain size, hardness and resistivity.
Up to 7 cycles of ARB the average grain size continues to decrease, and both the hardness and resistivity increases with the number of cycles, N.
Contributions of grain boundaries to the Fig. 1.
This work was supported by Grant-in-Aid for Scientific Research by Ministry of Education, Culture, Sports, Science and Technology, Japan, under project numbers 19025007, 19360288 and 21360311.

It is shown that the simulations can correctly reproduce the softening effect linked to a decrease in thickness and in number of grains across the thickness: the quality of the final shape strongly depends on the number of grains across the thickness.
For dimensions larger than a few micrometers, these modifications involved by miniaturization are due to a decrease in the number of grains across the thickness (also called thickness to grain size ratio, t/d ratio).
(a) Barkhausen noise in plastically strained Nickel with two different grain sizes [6].
Optimization of the mechanical properties of this product is typically a size effect because of the very small dimensions of the IMC interlayer and the weak number of grain through thickness for copper external layer.
Geers, An experimental assessment of grain size effects in the uniaxial straining of thin Al sheet with a few grains across the thickness, Mater.

After homogeneous grains developed, further grain growth became restrained. 1.
Introduction Though nanocrystalline materials possess a large number of grain boundaries that may act as driving force for the grain growth, experimental results indicate that most nanocrystalline materials exhibit a remarkable resistance to grain growth [1-3].
After homogeneous grains developed, further grain growth became very slow.
These grain boundaries motion resulted in selective grain growth.
After homogeneous grains developed, further grain growth became Fig.3.

The Consistent Description of Crack Developing Process based upon COTTRELLˊPiling up of Dislocations Model Aimin Yang Institute of Materials Science and Engineering, Xi`an Shiyou University, Xian, shanxi, 710065,china amyang@xsyu.edu.cn key words: Crack Nuclearation, Criterion Number, Fracture Toughness, Brittle Material Abstract.
Thus, the nuclearation life can not be determined, which is more important for some materials, such as high strength materials[2], most of their life come from the nuclear component.From the practical point of view, Manson and Hirschberg put forward [3] the "engineering crack size" concept, meaning through the 3 to 4 grains in the crack size range, 0.076 ~ 0.1mm on the fine grain or 0.1 ~ 0.25mm on the coarse grain, which can be considered as the crcack nuclearation size.
Now set ，Xp can be seen as Crack Nuclearation Criterion Number; when，crack nuclearation does not occur；when，crack nuclearation ocuurs；so the role of Xp is similar to Reynolds Number in fluid mechanics.
Crack Nuclearation Criterion Number Xp reflects the combined effects of stress field in crack tip and resistance of material to stress, which is more reasonable than the crack fracture toughness.
In this way, with the new concepts “Crack Criterion Number”, the parts of the crack Nuclearation and the part of the crack expansion can be clearly distinguished and described Conclusion 1）the crack Nuclearation capability of Material can be characterized with the crack Nuclearation touchness Kp，and when，the crack Nuclearation ocuurs； 2）Criterion Number Xc is suggusted for describing the different crack development steps for the brittle material: 3）Crack Nuclearation Toughness is 1/2 of Griffith Fracture Toughness for the brittle material..

Plate-like Mg2Sn-particles were found coupled with MgZn2-needles inside the grain, as well as at sub-grain and grain boundaries.
Large precipitates are located at grain boundaries; near grain boundary (NGB) zones are depleted of precipitates.
parallel to the grain boundary.
The number of fully dissolved layers may serve as a dimensionless width of a precipitate depleted zone Discussion In agreement with previous reports [10,11] and according to the present work, during the aging of solution treated and quenched Mn-SnZn alloys, the hcp-MgZn2 precipitates nucleate homogeneously (possibly on vacancies or vacancy-Sn clusters) in the body of grains as well as heterogeneously on grain boundaries.
The dimensionless calculated width of PDZ's (the number of fully dissolved precipitate layers) and experimental values of the PDZ width after different aging periods correspond with the dependence (w/d)~1/3 that is characteristic of normal coarsening.

The casted material had a columnar grain structure with a grain size of several millimeter.
The band structure in grain C continues through the grain boundary into the neighbouring grain A (Fig. 2).
C CD grain B CD c) B A grain C CD grain A CD b) a) d) Fig. 2: Band structure near the grain boundary AC comprising several groups of parallel microbands.
Formation of new grains.
In this study, the specimen contains just some few grains and also the deformation conditions are not exactly defined due to low grain number, friction and specimen geometry.