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Both materials possessed well defined high-angle grain boundaries.
Introduction There are a number of methods available for the manufacture of nanocrystalline metals, one of which is electrodeposition [1,2].
There have been a number of theories presented to explain internal stresses.
Dark field images were also used to determine the average grain size by counting at least 200 grain diameters for each material.
The addition of iron also caused a decrease in grain size.

Experimental Study on Compaction and Strength Characteristic of Wetland Fine Grained Soil Hongxia Yang School of Civil Engineering, Shandong Jiaotong University, Jinan, Shandong, 250023, China yanghongxia0531@163.com Keywords: Wetland, Fine grained soil, Compaction curve, Strength.
This paper through test study on the compaction and strength of several typical fine grained soil subgrade filler come from Ji-He expressway wetland soil field, discusses compaction characteristics of the fine grained soil under the condition of moisture content changes in a wide range,and change rule of compaction soil unconfined compressive strength and CBR value with the compaction work and moisture content.
Table 1 The fine grained soil physical property indexes No.
A large number of construction experience also shows, the moisture content is close to the optimum moisture content conditions,using made in China roller generally able to achieve the degree of compaction of the heavy standard, but for a higher moisture content over wet soil, it is difficult to achieve heavy standard requirements the degree of compaction.
[5] Hua Li.The Family of Compaction Curves for Fine grained Soils and There Engineering Behaviors.University of Alberta.2001

The strong elastic stress accumulated by shearing texture is responsible for oriental growing of a great number of grains during recrystallization.
A number of unusual properties have been reported in ultrafine grain materials produced by severe plastic deformation (SPD).
AARB effects on grain refinement.
From fig.3(a) and (b),we can see that gains were squashed and there were subgrains which have low angle grain boundaries appear.This was because that friction of inner grains and grains was intensified,and grains in the place of grain boundaries occurs slide,and crystal plane in part grains occurs glide when rolled pieces pass crossover area,meanwhile,because of the effect of AARB,2/3 large grains transform numerous subgrains which have low angle grain boundary ,i.e.2/3 large grains were broken into numerous small subgrains whose size are about 5um;from fig.
The strong elastic stress accumulated by shearing texture is responsible for orientable growing of a great number of grains during recrystallization.

The dependence of P1 and P2 on grain size indicates that the two peaks are originated from the grain boundary sliding, and P3 may be associated with the diffusion of Ce atoms or other impurities at grain boundaries.
It is well known that the solubility of solid solution of Ce element in Al is very low, and with annealing temperature or deformation rate increasing the segregation of Ce atoms may take place at grain boundaries.Based on the grain boundary sliding model, the grain boundary sliding is restricted by the triple grain boundary when the grain size is smaller than diameter of the sample.
Ke also discovered that the height of bamboo peak was proportional to the number of bamboo grains [6].
At a higher annealing temperature, more Ce atoms gathered to form participating particles at grain boundary, these participating particles may act as blockings to restrict the grain boundary sliding instead of the triple grain boundary.
Mori also found that participating particles at grain boundaries can act as triple grain boundaries to restrict the stress relaxation across the grain boundary when the bamboo peak appeares [7].

By this method, the material grain size can be refined to 20~200nm, which are nanometer level.
Fig. 5(a) is a line chart of the effective strain of these seven points when the number of torsion is 0.5, 1, 1.5 and 2.
The grain gets finer and more homogeneous when the number of turns increases [7].
This is the reason for the central area owns a larger grain size but edge area owns a smaller one.
This inhomogeneity gets smaller, and the strain increases with the number of turns increases which get the grain refined.

The results showed that the number and size of recrystallized grains increased with the increase of temperature at the same strain rate, and the number and size of recrystallized grains increased with the decrease of strain rate at the same temperature.
The dislocation increment rate will increase as the increase of strain rate at the same temperature, and a large number of deformation dislocations will be accumulated at the grain boundary soon, resulting in the increased of deformation resistance, so the peak stress will increase.
Microstructure Evolution and Recrystallized Grain Size of Mg-13Gd-4Y-2Zn-0.5Zr Alloy.
Therefore, the grain size model of dynamic recrystallized is as follows:
The grain size model of dynamic recrystallized is constructed as: .

This confirms that large grains are already recrystallized after ECAE. 0 5000 10000 15000 20000 30 50 70 90 110 130 Image quality Number ECAE 30s 7min30s Fig. 5 : Number of indexed points versus image quality.
Inspection of grain size distributions shows that, after 30s annealing, the number of the smallest grains (<0.5 µm) has slightly increased whereas the number of large grains (>1.5 µm) has remained constant (Fig. 6a).
Indeed, the average size of dynamically recrystallized grains (IQ>70) remains constant and equals 1.4 µm after 30s annealing. 0 100 200 300 4000.1 1 10 Grain size (diameter) (µm) Number ECAE 30s 7min30s (a) (b) Fig. 6 : a) Evolution of grain size during copper annealing at 473 K, b) Distribution of image quality of small grains (<0.5µm) after 30s annealing.
After 7min30s annealing, the number of large grains increases at the expense of the small ones.
As already suggested by the EBSD analysis and the hardness curve, this result confirms that, after 30s annealing, the copper is still recovering and the number of new oriented recrystallized grains, is not sufficient to change the texture.

Predictive theory for the grain boundary character distribution K.
Although we may be reasonably confident that small cells with small numbers of facets will be deleted, their effect on the configuration is essentially random.
An entropy based theory of the grain boundary character distribution.
Mullins. 2-Dimensional motion of idealized grain growth.
Smith "grain shapes and other metallurgical applications of topology".

The effect of nitrogen on crystal grain for metastabl austenitic manganese steel was studied.
Table 1 lists main chemical composition of experimental steels and according crystal grain grade.
Table 1 Main chemical composition of experimental steels and crystal grain grade Heat number Main chemical composition Crystal grain grade w([N]), % w([Cr]) , % w([Ti]) , % 1 no yes no 1 2 0.120 yes no 2 3 0.070 yes no 4 4 0.055 yes no 1 5 0.050 yes no 1 6 0.067 no no 3 7 0.120 yes yes 3 By analyzing the data of nitrogen content and crystal grain grade of experimental steels listed in Table 1 and the metallographs of experimental steels showed in Fig. 2, it can be seen that the grain grade of experimental steels will be influenced by nitrogen content.
But grain grade of No.7 heat is same as No.6 heat’s alloyed with only lower content nitrogen.
The Effect of Nitrogen Element on Growing of Crystal Grain during Heat Treatment.

At this time, the number of wearied and newly presented cutting edges arrives at homeostasis due to self-truing tendency.
A number of experiments performed in the past indicated that, for abrasive granule used in ultra-precision grinding, the grain diameter obey to truncated normal distribution, which means 99.7% of grains in grinding have size in [ max min, gg dd ].
Therefore, probability density function ( )gidP of grain diameter gid can be expressed as [4,8] ( ) max ggi min g 2 g ggi g 1 gi ddd; ;0 dd 2 1 exp 2 A dP <<                       − − = σ πσ (4) Where min gd and max gd is minimum and maximum grain size respectively, gσ is standard deviation and gd is mean which can be calculated by sieve number M and expressed as 1 2.15 − = Mdg [4,5,8], and 1A is test constant.
Numbers of such dressing tool topographies engage in the same place of abrasive, which work as an inerratic integral mode, made cutting edges equably at a certain level on the tool.
Hence, the grain protrusion number can be identified along with grain protrusion height hg by section height h and grain occurrence.