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In comparison, only a small number of such reports are available on cast materials.
Although ductility improved with higher numbers of working cycles, the strength decreased.
However, since a limited number of reports relating the fatigue properties to the presence of fine grains are available, the relationship between fine grains and various mechanical properties must also be elucidated.
The ratios of high-angle grain boundaries with misorientations of 15° or more for the as-received cast (measured area = 1500 µm x 1500 µm) and extruded materials (600 µm x 600 µm) are 90% and 85%, respectively, and the ratios of twins to these numbers are 55% and 5%, respectively.
However, the maximum stress amplitudes at low numbers of cycles were 25 and 40 MPa, respectively.

In the process of grain stocking, in grain pile, some concrete conditions such as temperature, grain moisture and air humidity could cause grain heat and blight which exert unnecessary loss on grain depots.
When the abnormality of grain state occurs, to ensure the safety of grain storage process, some corresponding measures could be taken.
To inquire the temperature of a certain point, before conducting temperature query it is necessary to determine the serial number of this point.
Therefore, it is essential to search for all the globally unique 64-bit serial number of DS18B20 on single bus before measuring temperature.
Interworkging diagram Digital humiture sensor is applied in grain measurement and control system to gather temperature of grain.

In this case, a number of grains to thickness would be one or two.
It is reported that the mechanical properties of thin metallic films are dependent upon the number of grains per thickness, if there are < 10 grains per thickness.
Thus, in the general thin films with very fine grains, the film thickness plays as a dominant role rather than the grain size.
Fig.6 Grain size dependence of yield strength (a) and ratio of thickness to grain size dependence of yield strength (b) Size effects in fracture strain of thin films were found by a number of authors [1, 5, 11-13].
Therefore, an increase of a number of grains per thickness would increase a resistance to necking fracture.

N, Dv and c eq, denote the number of atoms per unit volume, the vacancy diffusivity and the thermal equilibrium vacancy concentration, respectively.
This implies that vacancies generated at grain boundaries have to travel across a grain before they get absorbed by a grain boundary and further transported to a free surface via grain boundary diffusion.
This yields for the vacancy concentration eq cc λ= , (6) where Journal Title and Volume Number (to be inserted by the publisher) 3 ( )     += βδ γ λ NkT4 1
The linear grain growth stage extends to the grain sizes for which vacancy sinks other than the grain boundaries will emerge.
Journal Title and Volume Number (to be inserted by the publisher) 5 It should be stressed that in contrast to the classical diffusion creep that does not show a primary stage, the present model predicts a transient behaviour that is effectively tantamount to primary creep followed by a steady state creep stage.

Furthermore, in calcia added samples, grain growth was much faster and lots of micro-pores were left in coarse pure yttria grains.
This procedure was repeated until the destruction of the sample, and the number of quenches was taken as the measure of thermal shock resistance.
Moreover, the EDS results revealed that grains less than 1μm on the grain boundaries were calcia contained yttria solid solution and coarser grains about 5μm or 30μm were pure yttria.
Simultaneously, because of the increased high grain boundaries mobility, micro-pores were inevitably left in coarse yttria grains.
Because of the existence of calcia, the migration of yttria grain boundaries was increased and micro-pores were left in coarse yttria grains.

A number of SPD processes such as accumulative roll-bonding (ARB) [2-6], equal-channel angular pressing (ECAP) [7], and high-pressure torsion (HPT) [8] have been developed to produce ultra-fine grained (UFG) structures.
Such strain-rate dependency became more obvious with a larger number of ARB cycles.
Figure 3(a-c) shows the grain boundary maps of the AA8011 specimen ARB-processed at various numbers of cycles.
The distributions of the grain boundaries determined by the FE-SEM/EBSD analysis are summarized in Fig. 3(d), where it can be clearly seen that the fraction of high-angle boundaries increases with higher numbers of ARB cycles.
The total elongation experimentally obtained and that calculated from Eq. (1) as a function of the number of the ARB cycles.

This is explained by considerable relaxation of the internal stresses in the deformed steel caused by appearance at ε > 20% of a great number of microtwin packages.
The dotted line shows the average internal stress values The distribution analysis showed that both at simple and complex grain bending of a grain one sees the inhomogeneous polycrystal grain deformation.
Consequently, the number of more stressed sample sections (σ > 2 GPa) is insignificant.
It should be also pointed out that the total area of the second and the third mode for a grain with complex bend is greater than for a grain with simple bending, i.e. the number of sample sections with the internal stress increasing 2 GPa is greater at complex grain bending than in grains with simple bending.
This is explained by considerable relaxation of the internal stresses in steel caused by appearance at ε > 20% of a great number of microtwin packages in the deformed material.

Namely, the new grains resulted from a progressive evolution of strain-induced grain boundaries, the number and misorientation of which gradually increased during deformation.
The new grains evolve in place of deformation subgrains, when the misorientations between subgrains attain values, which are typical of ordinary grain boundaries.
The new ultrafine grains appear at the frequently corrugated original grain boundaries and their triple junctions as well as at the deformation microbands.
Then, the rapid reduction in the grain size takes place in the strain range of 0.8 < e < 1.2 followed by a decrease in the grain refinement rate at larger strains.
On the other hand, a progressive increase in the misorientations among the uniform subgrain structure at high temperature results in simultaneous development of a number of the DRX grains at large strains.

These concentration profiles are built up simply by determining the number of particles that have reached a given distance from the particle source after time t.
It is clear that a tracer atom need not sample a large number of grains and grain boundaries in order for its diffusion coefficient to be given by the Hart Equation (Eq. 3).
He used an f.c.c. lattice rather than the usual simple cubic lattice because it provides for a larger number of grain boundary orientations for a given mesh size.
A number of Monte Carlo calculations have been made in which grains are represented as cubes or as spheres in various configurations with and without segregation [24-26].
Ratio of Deff (as obtained from the Hart Equation) to Deff (as obtained from the Maxwell Equation) as a function of g for values of Dl /sDgb ranging from 10 -3 to 10 -8 (lines are marked with corresponding numbers).

The grain boundary ensemble formation in UFG materials and its evolution under thermo-mechanical treatments The current use of electron backscattered diffraction devices recording misorientations of a large number of grain boundaries allows revealing that the grain boundary ensemble of SPD-processed UFG materials contains an entire spectrum of low- and high-angle boundaries.
In the range of high-angle misorientations the total number of grain boundaries with misorientation of 45–60° is observed to increase (Fig. 3).
The nucleation of new grains induced by grain boundary diffusion fluxes of Ni is supposed to change the spectrum of grain boundary misorientations in UFG molybdenum.
It should be noted that the nucleation of new grains at triple junctions and migration of grain boundaries due to the grain boundary diffusion of Ni were earlier observed in coarse-grained molybdenum as well [19].
However, the latter type of loading induces opposite changes in the fraction ratio thus decreasing the number of low-angle boundaries and increasing the number of high-angle boundaries.