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After T6 treatment, a large number of intermetallic compounds of Mg24Y5 with Y are precipitated from the alloy and the second phase has changed significantly in size and morphology which is uniformly and widely distributed in the grain and grain boundary with a good strengthening effect.
The grain formed by cooling of alloy liquid generally includes three categories: fine equiaxed grain on the surface, internal columnar grain and coarse equiaxed grain at the middle.
Since the grain boundary of equiaxed grain is long, impurities and defects are distributed dispersedly and the phase of different grain is different, its directivity of property is low and relatively stable.
At the same time, a small number of acicular compounds are also seen inside the grain which may be stable phase at high temperature left from cast structure and networking eutectic structure concentrated at the grain boundary of alloy after heat treatment completely disappears.
In meanwhile, after the casting second phase is discomposed, there is a large number of uniform and dispersed spot phases to precipitate which are an important factors of strengthening.

The number of rolling pass was 40 and 30 for RT rolling and warm-rolling, respectively.
The number fractions of the two characteristic crystal directions along RD, i.e.
Meanwhile, the number fraction of RD//<001> texture increases from 0.18 in RT rolling to 0.35 in 923K rolling at the tolerance of 15o .
In contrast the number fraction of RD//<110> texture nearly keeps constant at about 0.5 at the different rolling temperatures.
The number fraction of the cube texture increases obviously with rolling temperature.

Austenite grain size does not exceed ASTM number 6.
Austenite grain is refined with increasing bismuth content.
Austenite grain size in lead and bismuth steels is the same.
Presence of bismuth refines the austenite grain of the forged steel even if aluminum content is critical and cannot provide grain size of ASTM number 6 (Table 6).
Austenite grain size is not greater than ASTM number 6.

In the solution about 30 µm andlinear grain boundaries (Fig.2a).
Indeed the presence of small carbides at the grain boundaries (Fig.1) seems to strengthen the grain boundary.
This seems to be confirmed by the reduced number of cracks detected near the fracture surface from cross-sectional observations (Fig.5).
properties was attributed to the presence of small carbides and the tortuous morphology of the grain boundaries.
serrated grain boundaries providedan This enhancement of the tensile properties was attributed to the presence of small carbides and the tortuous morphology of the grain erstand the role of the grain boundary containing heat resistant austenitic stainless steel.

M = magnification n = number of particles nd = total number of dislocations intersecting a surface area (NA), (NA) = number of and grains per unit area NA = number of grains per unit area Ni = number of grains intercepted by the field of view of the image (NL) = number of intercepts per unit test line length (Np) = total number of intercepts Nt = total number of grains NV = total number of particles in volume (Nv)1, (Nv)2,...
,(Nv)max = number of spheres in each class interval Nw = number of grains enclosed within the field of view of the image PP = point fraction Pβ = number of test grid points associated with particles Pβ' = total number of test grid points lying completely onto particles Pβ'' = total number of tangential test grid points to particles (Pp) = point fraction of the particles PL = number of point intersections per unit test line length Pt = total number of point intersections or test grid points R = distance between any two spots on a diffraction pattern SEM = scanning electron microscope SV = surface area per unit volume TEM = transmission electron microscope t = specimen thickness VV = volume fraction Introduction Most material properties depend on the microstructure and this has been proved for various materials such as superalloys, composites, steels and aluminium alloys [1-4].
Nt=Nw+½Ni (7) where Nt = total number of grains, Nw = number of grains enclosed within the field of view of the image (e.g. grain A) and Ni = number of grains intercepted by the field of view of the image (e.g. grain B).
For these non-spherical microconstituents, stereological equations relating the number of faces, edges and corners of polyhedron-shaped grains to equivalent grain diameter have been proposed from studies such as those by Matsuura et al. [24].
,dmax, respectively and NV = total number of particles in volume.

For diffusion creep n = 1.0 whereas n is frequently close to 2 for grain boundary sliding (i.e. superplastic regime), both mechanisms being promoted by a grain size reduction, the value of p varying from 2 when lattice diffusion is controlling or 3 when grain boundary diffusion is controlling.
Thanks to such analyses, various data like the volume fraction of cavities, the size and shape distributions of the number of cavities per unit volume can be measured in in situ conditions.
Figure 4 displays the variation with strain of the number of cavities as well as 3D observations of the population of cavities for two strains: ε ≈ 0.13 and ε ≈ 0.35.
A continuous increase of the number of cavities is detected and values of several thousands of cavities per mm3 are measured.
The 3D observations of the population of cavities confirm clearly that the number of detected cavities increases significantly with strain.

But the fine sand has some characteristics as grain uniformity, badness gradation, single structure, and the fine grain, and the fine sand filling subgrade is built on the soft soil foundation with high water table, so it is hidden troubles for the fine sand filling subgrade extending and application whether it can liquefy under the tempestuous earthquake load.
But the fine sand has some characteristics as grain uniformity, badness gradation, single structure, and the fine grain, and the fine sand filling subgrade is built on the soft soil foundation with high water table, so it is hidden troubles for the fine sand filling subgrade extending and application whether it can liquefy under the tempestuous earthquake load.
The grain characteristics of fine sand filling The sand engineering characteristics such as penetration, compressibility and strength are mostly depending on the sand grain gradation.
（6） Fig. 2 Liquefaction strength curve of sample 1 Fig. 3 Liquefaction strength curve of sample 2 Table 3 The liquefaction test analysis results Test number Effective confining pressure /kPa Measured data 7。
Conclusions The test results analysis shows that, the fine sand has uniform particles and bad gradation, and the structure is single grain structure with fine grain.ine grain.

The number of pores was higher with the gain fraction of grain boundaries.
The porosity was related not only to the number of pores but also to the pore geometry.
The grains in all the three specimens were attached well to the neighbor grains.
A high number of pores were noticeable in the 3 h milled specimen.
The 4 h milled specimen showed relatively a few numbers of pores than the 3 and 5 h specimens.

Grain size in brass scatters from 10 to 200 µm.
The increase of number of various facets roughly correlates with decreasing grain size.
In case of twin GBs each 3 rd lattice site of a grain 1 coincides with a lattice site of a grain 2, and Σ = 3.
It can be seen that the number of crystallographically different facets increases with decreasing temperature.
Indeed, it can be seen from the Table 1, that the number of various facets is really larger in samples where the grain size is lower.

An analysis of strength and ductility of ultrafine grained Al alloys R.
Over the last two decades a number of secondary processing techniques have emerged, with the primary aim of refining the microstructure to characteristic length scales near or below 1 µm.
This may be due to the more elongated grains and the lower fraction of high angle grain boundaries present in ARB alloys.
Micro-shear bands form during deformation and impinge on grain boundaries.
Effect of grain boundary character on ductility In addition to the important influence of grain size on ductility, the nature of grain boundaries also play a major role.