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The sintering process leads to neck formation and the removal of internal pores, resulting in grain growth of the source powder [4].
The grain growth could be directly linked to the improvement of SiC powder sublimation [5], however, the aspect of the SiC crystal could change with the use of different grain sizes of source powder, even under identical growth conditions.
Since the neck formation was conducted at relatively lower temperatures between 1500 and 1600°C, the grain growth was suppressed, and the minimal inter-grain bonding maintains the shape of the powder. 5) The inner crucible was removed after the heat treatment.
However, the path for source gases during grain growth can be clearly observed in the CT images for designs B and C, despite the presence of a large recrystallization region within the source powder.
Acknowledgements This work was supported by Technology Innovation Program (Project Number : 1415185945, P0012451, 2024) funded by the Ministry of Trade, Industry and Energy.

Its grains were used as the source material to deposit thin films by vacuum thermal evaporation.
Thereafter, the bulk alloy was got out from the ampoule and ground into grains.
GeS thin-film samples were deposited by thermal evaporation of the synthesized GeS grains using a molybdenum boat at a deposition rate of about 1nm/sec. onto carefully cleaned glass substrates.
Doped samples with 1, 2, and 3 at.% indium were prepared by the simultaneous thermal evaporation of GeS grains and the desired indium atomic weight percentage of purity 99.999% (obtained also from Balzers, Switzerland) which was evaporated using a molybdenum boat.
Although the atomic number z of indium dopant is 49, its concentration in the film samples is not quantified by EDS technique, as is evident in Fig. 3, since it is expected that the indium characteristic X-ray peaks Kα and M are at 3.286 and 0.368 keV, respectively [14].

Oxygen permeation proceeded via grain boundary (GB) diffusion of oxygen from the higher PO2 surface to the lower PO2 surface, concurrently with GB diffusion of ytterbium in the opposite direction.
By contrast, the interdiffusion of oxygen and cations in actual EBCs is simultaneously affected by various factors, such as dµO, grain growth, and reactions with hetero-phase interphases.
Thus, PL·Sgb–1 was independent of the grain size of the wafers, depending only on the GB characteristics.
The GB diffusion coefficients were expressed in terms of Eqs. (9), (10), and PO2, given by Arrhenius equations incorporating the frequency factor and activation energy: ， 　 (9) , 　　　　　 　　 (10) where d is the GB width, CYb and CO are the molar concentrations of ytterbium and oxygen per unit volume of YDS (2.39×104 mol·m-3 and 8.36×104 mol·m-3, respectively), and te' is the electronic transference number.
Azar, A disconnection mechanism of enhanced grain boundary diffusion in Al2O3, Scripta Materialia, 102 (2015) 15-18.

RESULTS AND DISCUSSION Precipitation OM and SEM examinations of the spiral wires and cross-rods from belt B1 operated in the standard furnace atmosphere and belt B2 after service in the modified atmosphere revealed precipitates on grain boundaries and within grains.
SEM/EDX microanalysis revealed that the particles on grain boundaries and within grains consist of chromium and carbon, or chromium, carbon and nitrogen, or chromium and nitrogen, which indicates that they are chromium or chromium-rich carbides, carbonitrides, or nitrides.
The internal oxidation depth is highest in the areas containing silicon oxide that was formed along grain boundaries.
The amounts of chromium-rich carbides, nitrides or carbonitrides on grain boundaries and within grains depend on the carbon and nitrogen contents of the material.
Even though the average elongation of the B2 cross-rods was higher than the corresponding value of belt B1, the difference in elongation is not statistically significant, which may be related to the low number of test samples.

One of the most successfully and frequently used ceramic material is boron carbide B4C, which has a number of unique properties.
A pore free microstructure consisting of B4C grains surrounded with fine grains of (Ti0.9W0.1)B2 and W2B5 formed due to WC contaminations was obtained.
It was shown that formation of boron carbide in the presence of WC, WC–Co and Co promotes sharp reduction in its grain size.
Korkia, Synthesizing fine-grained powders of complex compositions B4C–TiB2–WC–Co, Solid State Sci. 108 (2020) 106439 (1-8)
Chedia, Method of obtaining multicomponent fine-grained powders for boron carbide matrix ceramics production, Mater.

A myriad of such pools are probably located along grain boundaries in the sample.
Thus, for example, while 111In probes in Ni2Al3 occupy one of two inequivalent Al-sites in Ni-rich samples, in Al-rich samples they are “ejected” to non-lattice sites such as grain boundaries that exhibit inhomogeneously broadened, quadrupole interactions [5].
Thus, it is concluded that, just as in Al-rich Ni2Al3, indium in Ga-rich FeGa3 gets expelled from the crystal structure, here becoming dissolved in small liquid pools of excess gallium that are probably located at grain boundaries.
The 111In activity is purchased in carrier-free form [[] Perkin-Elmer, catalog number NEZ-304. ], and only an activity of 10 microcuries is introduced into a sample for the measurements, corresponding to 1010 atoms.
At 293K, all probes were excluded from the compound and determined to be mostly in small pools of supercooled gallium metals that were probably located in grain boundaries of the compound.

The aim of these processes is to introduce high values of deformation inside the parts in order to reduce the grain size and thus to improve the mechanical properties of the starting material.
This is achieved by means of the reduction in the grain size up to micrometric or even nanometric values [1].
In the table, DF represents the number of degrees of freedom.
In elements, the number of nodes in the cross-section is approximately 280 whereas the number of positions studied for the evaluation of microhardness is, as was mentioned, 32.
Nevertheless, this can be only carried out a specific number of times until the fracture of the material occurs.

The light phase is the primary-(Mg) crystals (grains) and the solid phase in the semi-solid billet.
One of the aims of semi-sold processing is to produce the primary phase in the shape of spherical globules (grains) but there is always a tendency to rosette shapes due to the compositional segregation field around globules during solidification.
No attempt was made to quantify the grain size because of the lack of sphericity in these initial trials.
Fig. 3 also shows clearly a number of small particles in all three magnesium alloys in the T4 condition.
Govender, Semi-solid rheocasting of grain refined aluminum alloy 7075, Trans.

Processing these materials for reproducibility and reliability in behavior is not easy, as they are sensitive to minor changes in sintering temperatures and times and many other processing condition such as Ca/Cu ratio and anomalous grain growth.
At present, the grain boundary barrier layer capacitance model of extrinsic mechanism is the most favorable, which is very similar to the nature of internal barrier layers capacitors(IBLC).
A certain amount of citric acid (C6H8O7·H2O in the ratio of 1:1.5 of sum of the metal ions to the number of moles of citric acid) was placed into as complexing agent.
From the SEM photographs, we can see that prepared samples CaCu3Ti4O12 and CaCu3Zr0.05Ti3.95O12 are composed of many grains, the grain boundary effect can make a major contribution to the high dielectric constant of polycrystalline CCTO-based ceramics.

From Fig. 3(b)~Fig. 3(d), it can be seen that there was biggest indentation depth in the center of specimen after different deformation modes, and the indentation depth at the edge of the specimen was the minimum, this was because after a single torsion, tensile-torsion and compress-torsion deformation, the accumulated equivalent plastic strain gradient increasing from center to edge of the specimen, and the increase of plastic strain caused grain internal dislocation multiplication and dislocation density increases, so the strengthening effect was more obvious.
These two phenomena indicated that after a different deformation mode, the edges produced the large plastic strain, a large number of deformation damage which caused Young’s modulus decreased.
The grain boundary crack growth is the key cracking mechanism in molybdenum due to the instinctive brittleness of its grain boundary and impurity segregation at the grain boundary [6].