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Metallographic Estimation of the Number of Forming Metallic Particles Obtained during Direct and Indirect Reduction of Metals from Complex Oxides A.S.
The technique was developed by using the two different software programs for the quantitative estimation of the areas, average size and number of the metal forming in a complex oxide with extensive fields of vision.
The Fe2+ and Cr3+ cations are reduced in the grains of chromium spinels (Al, Mg)(Cr, Fe)2O4 which present as impurities with content up to 5 wt %.
In the olivine grains of Fe0.16Mg1.86SiO4 iron is not reduced at this temperature.
The data about the area of each reduced iron particle, the total number of iron particles, the average size and the area of the total metal was obtained as a result of processing of the panoramic optical images of surface of the samples’ sections, Table 1.

Increasing the metal concentration causes the grain size to increase.
Further increase of the metal concentration leads to exchange interaction appears between grains.
The Ea value depends on the quantity of grains (N) in exchange-related areas.
Grain size increases with increasing of Fe concentrations and this leads to reduction of N.
Therefore, the Hc reduction in the range of 45 £ Fe, at.% £ 80 is associated with an increase of grain size because it leads to reduction of grain boundaries number and thus to reduce the number of the pinning centers.

The grain size becomes larger following the increase of the sintering temperature.
The higher the mobility of ions is, the larger the grain growth.
A ceramic with larger grains has smaller number of scattering center for charge carrier making the ceramic has lower resistance.
At 1100 oC, due to relatively low temperature, the grains of the pellet are relatively small and interconnection among the grains is few.
When the temperature is increased to 1300 oC from 1100 oC, the grains are larger and the interconnection among grains increases resulting in fewer scattering center for charge carrier and lower resistance.

The paper reports on the methodology used to conduct the initial simulations and concludes with a number of suggested simplified equations that will assist practitioners in predicting atomic diffusion for a number of materials.
Their work included an evaluation of a number of joint types including those ferritic to ferritic and ferritic to austenitic joints in use at that time.
A number of users consider that concentration gradients may be calculated using weights of alloying elements as a concentration ratio, (weight percent).
The evaluation of the available atoms is complicated by a number of factors, these are: • type of element, carbon, chromium, etc., • proximity, availability, and tendency of other carbide forming elements • types of carbides and existing carbides formed/types • likely carbide ratios • grains and grain size The concept of defining a tendency to form a carbide in this context was discussed by Bain in detail in 1939, [7].
On average, for the steels simulated the factor was adequate to describe a number of service behaviours.

A number of processing parameters including laser power, laser scan rate, powder feed rate, have been varied to evaluate their effects on the material soundness.
A number of experimental works dedicated to AM of g-TiAl alloys have been reported in the literature.
Eventually, a number of 10*10*10 mm cubic samples have been produced with the best processing conditions.
It can be observed that the initial dendritic structure consists of g and a2 grains of approximately 5 mm in size.
A uniform duplex microstructure was then obtained with lamellar g+a2 colonies as well as g grains.

These properties turn these ceramic materials good candidates for a number of application in electrochemical devices, ceramic coatings, catalysts, grinding media, biomaterials, etc.
The pellet containing 1 mol% Li (Fig. 2 top) shows homogeneous distribution of grain sizes and few pores, mainly inside the grains, as in samples without additives.
It is worth noting the drastic reduction in the mean grain size, and simultaneous observation of small grains preferentially at the grain boundaries and triple grain junctions.
This segregated secondary phase is responsible for avoiding both the grain growth and the trapping of pores inside the grains.
However, with increasing the lithium content, the magnitude of the grain and grain boundary conductivities decrease.

With increase of the coiling temperature, the grain has coarsening under the same cold reduction ratio.
Under diffrenent coiling temperature, with increase of the cold reduction ratio, the grain size of ferrite get more finer and uniform, and the grains are equiaxed.
That all because in the cold rolling, the grain deformed, and with increase of the cold reduction ratio, the number of the deformed grain increased, the deformation of the grain increased, then the dislocation density increased, the lattice distortion increased.
As in the annealing, the recrystal grain increase and uniform, the grain after recrystallization get finer and uniform.
If coiling temperature is too low, the grain size is finer, the final strength is higher , punching propertie will be deteriorated.

This control of grain growth is achieved via a microstructural mechanism known as Zener pinning [6].
For the equilibrium study, a number of tensile tests were performed in order to accelerate the rate of η phase precipitation in order to reach the equilibrium state sooner during subsequent heat treatments.
Within this wrought billet, the core regions were observed to be mostly large sized recrystallised grains whereas the rim regions were smaller sized unrecrystallised deformed grains.
Also, the smaller sized grains at the rim region would have provided more grain boundary area for precipitation to occur and hence would allow for higher area percentages of η phase at the rim region in comparison to the core region.
Rae, Grain-boundary precipitation in Allvac 718Plus, Acta Mater. 60 (6–7) (2012) 2757–2769

Moreover, the grain size of grapite is fine and the distribution is uniform, and the carbide mainly locate the ferrtie grain boundary or in the ferrite.
Calcium free cutting steel, which has coarse grain, low solubility in steel and difficult adds it to steel, results in low pass percent but high cost.
Due to the transformation temperature is high and the transformation time is short, the grain size of ferrite is relatively small (about 10 μ m, Fig.2b).
During the transformation of ferrite, a large number of C atoms eject into the untransformed austenite, which result in the content of C of untransformed austenite increasing and MS temperature decreasing.
It also can be seen in Fig. 3c that, the grain size of cementite is small and mainly distribute on ferrite grains or boundaries.

Preferential local corrosion of coarsen grain heat affected zone with the formation of occluded corrosion cell accelerated corrosion rate.
In addition, the grain size decreased from CGHAZ to FGHAZ, but the average grain size of CGHAZ was much smaller than that of BM.
Fig. 1 Microstructures of different zones in welded joint: (a) base metal; (b) fine grain heat affected zone (FGHAZ); (c) coarsen grain heat affected zone (CGHAZ); (d) fusion zone and (e) weld metal.
After 588 hours, corrosion pits only formed in CGHAZ near fusion line and the number and size of pits without applied stress was smaller than that with applied stress.
In addition, the smaller grain size in FGHAZ decreased corrosion susceptibility compared with that of BM.