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The number and size of pits still increases and the abrasive grains clearly project from the second to the tenth treatment.
In the case of 21 N, the projecting height of grains increase gradually with increasing the number of treatment till the tenth treatment but the projecting height of some abrasive grains is not enough yet.
In the case of 131 N, the projecting height of grains increase earlier than those at 21 N with an increase of number of treatment and increase approximately up to the maximum height of each grain at the fourth treatment.
Therefore the number of treatment, of which the projecting height of grain becomes steady, is defined as the effective number of treatment.
In the case of 0.0014m/s, the projecting height of grains increase gradually with increasing the number of treatment.

Recent research has shown an interest in this method, which can be declared with an increasing number of scientific publications or patent activities on this issue [1-10].
These measurements were supplemented by the measurement of changes in the speed of the longitudinal ultrasonic wave UZvl in the realized number of Nextr = 6.
The greater the grain size of the structure, the greater the irregularity and randomness in grain distribution and vice versa.
Grain distribution according to equivalent hekv depth.
However, it should be noted that in the system of our calculation methodology, the parameter h does not represent a single parameter variable, but is in mutual functions to a number of other parameters in the process.

Mechanisms of Ultrafine Grain Formation in Severe Plastic Deformation T.
The process of strain-induced grain formation can be subdivided in the following three stages irrespective of deformation temperature: i.e. an incubation period for new grain evolution in low strain; grain fragmentation by frequent development of MSBs in medium strain, and a full development of new grains in large strain.
The number of microband families running in various directions increases with further MDF, followed by a full formation of MSBs in large strain.
The authors proposed a model for strain-induced grain formation based on grain fragmentation by MSBs that is illustrated in Fig. 4 [8].
This subgrain-based model is assumed that new grain evolution takes place homogeneously in all grain interiors.

In these parameters, former three affect abnormal grain growth behavior through the austenite grain size after reverse transformation.
Abnormal grain growth behavior was evaluated by the area fraction of coarse grain whose austenitic grain size number was less than 5.
The grain size of sample C was measured from fine grain area.
(1) Where rcrit is the critical particle size at which abnormal grain growth occurs, Rm is a grain size of matrix, Z is the ratio of the radii of coarse and matrix grains.
Therefore, abnormal grain growth depends on the matrix grain distribution and the amount of pinning particles.

The process of plastic deformation in ultrafine grain titanium is considered.
A single diffraction peak (main reflex) or a number of diffraction maxima (subreflexes) would arise in the same area according to whether the material of the crystal has an ideal structure or is composed of individual crystalline blocks separated by low-angle boundaries.
A number of factors determine the angular resolution of the method: (i) the quality of a focused beam of X-rays, depending on emitter type and monochromator performance; (ii) the angle of reflexion and (iii) the extent of misorientation of crystallite blocks.
It can be seen from the histogram in Fig. 3 that subgrains and grains having sizes 0.1…0.4 μm account for 80% and non-equiaxial subgrains and grains having sizes 0.6…0.9 μm, the remaining 20%.
Fold-like meso-defects characteristic for ultrafine grain metals will form within the high-amplitude zone; the ultrafine grain structure of metal is characterized by the occurrence of non-equiaxed subgrains, which are elongated along the sample extension axis.

When the grain size is sufficiently small and dislocation-dislocation interactions and then workhardening is improbable, dislocations most likely interact with grain boundaries.
Compared to the first series, the relaxations depend on the relaxation number and on the strain history.
The apparent activation volume, * vΩ , increases with the relaxation number from about 30 3b to 40 3b , which indicates a transient domain with variation in dislocations density.
Slop at t=0 of the relative dislocations density as a function of the relaxation number.
This value is relevant regarding the fact that the fine grained copper is ductile and pile-up effect is observed at the indent.

The value of the varistor voltage depends largely on the number of conducting ZnO grains between the electrodes; this can be set by controlling the thickness of the device or the size of the grains.
Therefore, the break-down voltage of an ideal non-linear grain boundary is at 3V.
Although the voltage drop does not vary for grains of different sizes, the mean grain size and the grain size distribution play a major role in the electrical behavior of a device.
The value of the varistor voltage depends on the number of conducting ZnO grains between the electrodes, and this can be set by controlling the thickness of the device or the size of the grains.
Powder Ł consists of loose, plate-like, dense grains, while powder B is characterized by oval grains with a lower compactness that form small agglomerates that are easy to separate.

Most β grains experience recrystallization, while for those β grains which are hard to be swallowed by recrystallized grains only experience recovery after β region heat treatment.
As a symbolization of grain growth, the large misorientation within grains exsits in some large sized β grains.
We can see the existence of competition relationship in large sized grains from the relatively straight grain boundaries (between blue, green and red grains).
At 1/2R layer after forging, the number of recrystallized grains in β phase decreases and most β grains with numerous sub-structures formed inside process recovery.
Conclusions (1) Recovery and grain growth occurred in β grains; while partial β grains recrystallized after α+β heat treatment.

Therefore, we proposed a new calculation model for austenite grain growth [3], which is based on the kinetic equation for grain growth via the Gibbs–Thomson effect.
In the phase-field method, each grain is distinguished by an ID number used to track every instance of grain growth and disappearance.
The grain growth rate of steel A is higher than that of steel B.
The grain boundary mobility increases as the temperature increases.
The theoretical grain growth estimated by the proposed model was consistent with experimental grain growth in the distribution of the prior austenite grain size in HAZ after submerged arc welding.

The high elongation of ferrite grains facilitated simultaneous homogeneous nucleation of austenite grains throughout the matrix upon heating; and, therefore, promoted the development of ultrafine grained structure with the size of structural elements well below 1 micron.
An average grain size in the annealed state was about 10 mm.
The relatively coarse grained microstructure consisting of equiaxed grains (the grain size is 2.3 mm) that contains many annealing twins evolve in the sample annealed at 900°C (Fig. 4d).
However, the large number of annealed grains appears simultaneously throughout the deformation microstructure due to high density of grain/subgrain boundaries evolved by severe deformation.
The annealing behaviour of the rolled steel was characterised by the appearance of a large number of new austenite grains, leading to the formation of equiaxed submicrocrystalline structure with a average grain size of about 100-200 nm upon heating to 500°C < T < 800°C.