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Along with the remelting process, the columnar grain begins to grow to certain angle with axles, the shape of the metal pool gets closer to paraboloid shape.
(1) As the model is axle symmetric, in order to reduce the number of grid and save the computing time, half of the model was taken to calculate
The grain growth begins to be affected by the cooling of the side with the casting going.
The heat transfer at the bottom is more and more difficult, so the grain near the side begins to grow to the center along the opposite direction of the heat flow and the grain growth rate is also quick.
Reducing the coefficient of heat transfer at the side, the heat which distributes through the side decreases, so that the rate of heat transfer slows down and the grain mainly grows along axis thus the rate of grain growth slows down and the depth of the metal pool becomes shallower.

A large number of fine secondary-NiOss particles were separated from the CaOss crystal grains in CaO-NiO solid solution and improved the hydration resistance.
Once the sintered compacts are processed into grains of < 1 mm for the use to the nozzle as the raw material, the grains will be hydrated.
The microstructure of the sintered compacts is shown in Fig.9(a), which consists of white grains and a dark matrix.
EPMA analysis indicated that the white grains are a NiO rich solid solution (primary-NiOss) containing around 7 mol% of CaO.
A large number of fine particles (< 0.3 µm) were found to uniformly distribute in the matrix.

XRD, FESEM, SEM and EDS results showed that TiC-TiB2 composites were mainly composed of TiC matrix in which a number of fine TiB2 platelets were embedded, surrounded by the boundary regions consisting of (Cr, Ti) C0.63 carbides.
Recently, Vallauri [2] have successfully prepared the TiC-TiB2-MexOy ceramic composites of fine-grained microstructures by means of pressure-assisted combustion synthesis, and have confirmed the roles of the metal oxides as the promoter of the final product densification and the modificator of the grain refinement.
Furthermore, it was observed by FESEM that a number of fine platelets were embedded in TiC matrix, as shown in Fig. 3.
However, because of higher concentration and faster diffusion of C relative to B in liquid Ti alloy as well as the growth isotropy of TiC, TiC grows far faster than TiB2 does, so that the TiB2 platelets are completely surrounded by TiC grains, as shown in Fig. 3, and the final microstructures that a number of TiB2 platelets are embedded in TiC matrix are achieved.
In addition, FESEM images of the crack propagation paths demonstrated that as the crack is met by the large TiC grains, the crack propagates along the grain boundaries, and crack-bridging by TiC grains is initiated due to crack-branching effect, as shown by the arrow A in Fig. 5(b), subsequently, as the crack is met by the fine, hard TiB2 platelets, the crack is often arrested due to crack-pinning by the fine, hard TiB2 platelets, as shown by the arrow B in Fig. 5(b).

The number, size, shape and distribution of γ´ phase affect the using performance of the alloy.
Some carbide particles precipitated in the grain.
There is no primary γ´ phase in grain boundaries also.
Numbers of fine tertiary γ´ phases distribute around the secondary γ´ phases.
The number of γ´ phases of FGH95, FGH97, FGH98 are higher than FGH95, can ensure the strength of the materials[5].

The number of the defects in inner side was 1.5~2 times of that in outer side.
By this way, the defects number and location in whole plate were gotten.
(a) grains in slab (b) grains in hot-rolled plate Fig. 3 The grains in slab and hot-rolled plate Fig. 5 showed the distribution of the defects detected by ultrasonic test in the surfboard.
The number of the defects in inner side was 1.5~2 times of that in outer side.
The number of the defects in inner side was 1.5~2 times of that in outer side

The route B and C sample exhibited near-equiaxed grains of ~0.5 µm in size (Fig. 1-b and c).
The grains in the route A, B, and C samples were very fine and of a similar size.
This indicated a change in grain boundary characteristics from low-angle to high-angle grain boundaries with increasing ECAP severity.
Interestingly, the route B and C samples showed relatively equiaxed grains with irregular orientations.
Although the number of voids decreased with increasing distance from the fracture surface, they were still observed down into the interior distant from the fracture surface.

A fine grain structure with an average grain size of 3–17 mm was obtained by static recrystallization.
The average grain size of the specimens used in the previous studies was approximately 80 mm.
The notation used to refer to the specimens is summarized in Table 2, where the numbers following “d” represent the average grain size of the alloys.
Regardless of grain size, the value of fe was decreased by LTHT.
Acknowledgements This study was financially supported by the Japan Society for the Promotion of Science KAKENHI [Grain number: JP 19K23580, 18H01718 and 16J04279] References [1] F.

While both grain sizes and density of sintered samples were found increased from 1.4 μm to 2.46 μm and 90% to 98%, respectively.
The quantitative analyses were carried using the Rietveld method in Xpert Highscore Plus software to further clarified the number of phases formed accurately (as per Table 2).
The average grains size were observed 2.46 um.
Fig. 4: Average grain size of YAG with different sintering hour Density measurement: The relative density and grain growth of sintered YAG at various sintering temperatures and is shown in Fig. 5.
It is generally known that both the average grain size and density proportionally increased with longer holding times.

The formation of these ranges was attributed to the existence of two different modes of domain wall motion each of which was related to the grain boundaries as well as the grain interior activity.
Further, in Fig 3 the evolution of the logarithmic,, number of counts v.s. strain for the same six predetermined threshold voltage values,, is also shown.
One can observe that for a certain critical strain value an increase in the number of counts occurs resulting in a transition point of the magnetic activity.
In Fig 4 the evolution of the number of detected counts with the squared threshold voltage, , for certain elastic tensile strains (stress), is presented.
Fig 5 shows the evolution of the logarithmic counts number,, with increasing , for the same applied elastic strains as in Fig 4.

Electron backscatter diffraction (EBSD) analyses revealed a number of columnar α-Al grains with a mean size of approximately 10 μm.
STEM-high angle annular dark field (HAADF) image (Fig. 4(a)) shows a number of granular Fe-rich particles with a mean size below 100 nm formed inside the melt pools.
A number column grains with a mean size of about 10 μm appear twisted and elongated along the building direction in the LPBF-fabricated sample (Fig. 5(a)).
The fine substructure composed of high density low-angle boundaries was found inside the α-Al grains.
A number of columnar grains with a mean size of approximately 10 μm were found in the α-Al matrix.