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In the case of development of a composite without Co and taking into account the demand made, so that it can partially or totally replace the WC-Co based, it is necessary a larger number of analysis and testing to obtain key information that allows some conclusion on the feasibility.
Grains larger than 20 µm.
During sintering of cemented carbides the average grain size increases due to the grain growth.
This phenomenon is called Ostwald ripening .[9], i.e., large grains grow at the expense of small grains, leading to a stepwise increase of the average size every time a small grain vanishes [9].
Abnormal grain growth is observed when a few grains grow more drastically compared to the surrounding grains during the sintering process.

This mechanism involved the disappearance of low angle grain boundaries, which gave rise to the onset of a local grain coalescence mechanism that clusters grains that were only separated by low angle grain boundaries.
Chen et al. [14] observed that usually a small number of Goss grains grow during the early stages of secondary recrystallization.
It appears from these figures that disappearing low angle grain boundaries have a large impact on the nucleation of abnormal grain growth, although all theories of grain growth agree on the complete immobility of these grain boundaries.
As a large number of similarly oriented grains nucleate during primary recrystallization in one single deformation band of the deformed microstructure, it automatically produces the contiguous strings of grains that are only separated by low angle grain boundaries.
This gives rise to the clustering of grains that produces the long elongated grains at the onset of abnormal grain growth.

Preparation of Al-Ti-B-C Master Alloy and Its Grain Refinement Effect for Pure Al Z.Q.
The produced Al-Ti-B-C master alloys exhibited high grain refinement effect for pure Al.
The refinement efficiency of this master alloy, however, is reduced when elements such as Cr, Zr, Li, Si are present in aluminum; TiB2 particles in this master alloy are coarse and prone to agglomeration in Al melt, causing a number of product quality problems.
Results and discussion Two typical Al-Ti-B-C master alloys, Al-8Ti-2.4B-0.67C and Al-5Ti-0.82B-0.23C (the number before each element is its content in wt.% in the alloy) were produced in this work, and Fig.1 shows their XRD traces.
Since the formation of α-Al grain based on TiC/TiB2 particles occurs only when the supercooling at the particle-melt interface reaches a certain critical value[1], the additional supercooling due to Ti solute results in the incerasing of the number of effective nucleation sites.

Grains Growth.
Recrystallization and Recrystallized Grain Size.
During these tests the specimens were compressed different number of the deformations with variant deformation parameters.
The model is organized following a tree-structure, the depth being equal to the number of passes and each level is divided into two branches, the recrystallized and the unrecrystallized zones, respectively (Fig. 5).
This introduces the complexity of managing an increasing number of different structures throughout the deformation process.

In the last decades a lot of research focused on ultrafine grain microstructures (grain size lower than 5 µm).
With increasing the accumulated strain, pancaking of deformed grains increase and so the number of nucleation sites for ferrite increases.
Heavy Austenite Deformation The mechanism of Heavy Austenite Deformation has been investigated by means of a number of tests on samples of steels 30MnB4 and 18MnB2, deformed of 50 % at temperature Ar3+70°C at two different strain rates (1 s1 and 30 s1) and two different prior austenite grain size (10 µm and 50 µm).
Increasing strain rate is not effective on grain size refining: on the contrary, ferrite grain size tends to increase when strain rate rises.
Microstructure of steel 30MnB4 with UF ferrite grain size 3.3 µm.

The distinction between various ECAP routes with different number of ECAP passes applied may lead to variations both in the macroscopic distortions of the individual grains and in the capability to develop a reasonably homogeneous and equiaxed ultrafine-grained microstructure.
It has been proved that the effectiveness of the grain refinement depends on angle between two channels, number of ECAP passes and mode of rotation between consecutive passes.
With increasing the number of ECAP passes, the number of shear bands and dislocations was found to be increased.
In our recent work [13] it has been suggested that the coexistence of a dislocation climbing process and grain boundary sliding in creep of ECAPed material may explain the observed decrease of the creep resistance with increasing number of ECAP passes.
Fig. 6 The fraction of HAGBs in the crept samples as a function of the number of ECAP passes.

Also, there was a moderate effect of initial grain size on the DRX grain size.
Since the number of triple junctions in this fine grain material is much higher than that of the coarse grain, a lot of new grains were formed at these sites and, therefore, the necklace structure was not as pronounced.
Increasing the strain beyond the peak (Fig. 6b) led to more new small grains on the pre-existing grain boundaries or within the grains.
Fig. 7 shows the dependency of DRX grain size on the initial grain size as a function of Z.
As is clear in Fig. 7, there is a dependency of DRX grain size to the initial grain size and this dependency increases with decreasing initial grain size.

The expression of grain mass is used to predict the mass of grains.
According to the concept of fractal, Turcotte proved that the particle number-size fractal model can be expressed as [4].
According to the fractal theory, the number of panes of grains corresponding with measure scale L, N(L), can be expressed as [11], (1) Where is a constant, D is the area fractal dimension of grains.
The incremental number of pores, , is the incremental volume divided by the volume of one pore, (7) Where .
The total number of grains of size r or larger, , is the integral of Eq.(7) taken from the largest pore size, , to grain size r, (8) Where, (9) In Eq.(8), it is easy to confirm that is the density function of pore-size distribution, where is the pore-size distribution fractal dimension which is equal to the area fractal dimension of grains in Eq.(5) suppose the area shape factors of pores are the same.

The results of microstructure shows that the second phase particles pinned on grain boundary not only can inhibit the grain growth, but also the grain can be fined.
It is found that the large amount of second-phase particles is pinning on the grain boundary Fig.2（a）（b）, and the distribution on two sides of grain boundary is different.
The results are shown that the movement of grain boundary was inhibited by the segregation of the second-phase particles along the grain boundary.
The fine precipitates are hardly observed close to the precipitation free zone(PFZ) besides the small numbers of coarser precipitates.
(3) The results of microstructure shows that the second phase particles pinned on grain boundary not only can inhibit the grain growth, but also the grain can be fined.

Thus interference can be observed if the thickness of the film is an even number multiple of the quarter of the wavelength (λ/4).
If the lower velocity of the light in the film is also taken into account, interference will occur at the even number multiple of λ/4n, where n is the refractory index of the film.
The individual grains are numbered on both the color etched image and on the IPF map.
In order to define the colors quantitatively, a number was calculated for each color, applying the YUV color system [4].
Grain No.