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Furthermore, computed tomography (CT) was also used to elucidate the size, size distribution, number density, volume fraction of porosities.
Furthermore, computed tomography (CT) was also used to elucidate the size, size distribution, number density, volume fraction of porosities.
The volume fraction is 0.0026% and the number density is 0.0463 mm-3.
S9 (a) Band contrast (BC), (b) inverse pole figure taken from only the secondary α-Al grains, and (c) the number fraction of the secondary α-Al grains in the long thin samples with a relatively higher cooling rate produced by Al-7Si-0.3Mg based alloy with the recycled secondary materials of 20 % (F).
S11 Band contrast (BC), (b) inverse pole figure taken from only the secondary α-Al grains, and (c) the number fraction of the secondary α-Al grains in the large thick samples with a relatively lower cooling rate produced by Al-7Si-0.3Mg based alloy with the addition of recycled secondary materials of 30 % (H).

The crystal orientation obtained for each grain was used to estimate elastic constants of grains with an fcc structure.
Typically, the strain is large in grain E while it is small in grain A, as shown in Fig. 5 (c).
In other words, Young’s modulus is low in [100] oriented grains, and it is high in [111] oriented grains.
The grain images of the unloaded and tensile-loaded sample were obtained though the analysis of a large number of Laue patterns.
For instance, it is known that a large number of heterogeneous dislocations, which are called with geometrically necessary dislocations [9], are generated close to interfaces such as grain boundaries and twin boundaries.

Both coarse and fine grained CM247LC showed similar cyclic stress response, however, the fine grained CM247LC specimen exhibited relatively uniform and superior fatigue properties to the coarse grained one.
Experimental procedure Coarse grained (CG) and fine grained (FG) bars were prepared by vacuum investment casting of CM247LC.
Number of cycles corresponds to 80% drop in maximum tensile stress of the alloy was defined as fatigue life.
Relatively large amount of microporosity in FG was attributed to restriction of capillary feeding in mushy zone due to increased amount of grain boundary area and number of grains.
Number of cycles to failure as a function of total strain range.

Though the number is quite limited, the recrystallization also occurred inside the grain far from the grain boundary.
[m4s/J]　 (7) Here, is the amount of an alloying element which segregates to the grain boundary, α is the ratio of the segregation formulated by Eq. 8 (8) Here, δ is the thickness of the grain boundary, is the number of atoms in a unit volume, is the grain boundary segregation energy, is the Boltzmann coefficient and D is the grain boundary diffusion coefficient.
A constant n0 is the number of subgrains which start growing abnormally per a unit time.
　 (13) Here, N2 is the number of grains growing toward the center of the grain and is used as an adjusting parameter to fit the experimental result.
N3 is the number of the growing grains and is used as an adjusting parameter.

Furthermore, twinning is highly sensitive to grain size, with finer grain sized samples exhibiting a lower volume fraction of twins [3].
It means that the grain growth of the alloy is sensitive to the annealing temperature but the growth of the recrystallized grains is slight.
Table 1 date of the grain size and hardness of the annealed specimens.
These effects of orientation will be particularly important in non-cubic metals, due to the small number of their slip systems [13].
The strength anisotropy increases with decreasing grain size.

Moreover, the more the number of TiC particles synthesized in the melt, the finer the solidified austenite grains.
In this way, after the alloy melt was isothermally treated to form a great number of TiC particles, some unreacted carbon atoms were transformed into fine D-type graphite and aggregated at austenite grain boundaries during sequent solidification.
Moreover, the more the number of the synthesized TiC particles is, the finer austenite grains become.
A number of models were proposed to predict particle behavior in front of a moving solid/liquidt interface [7].
Moreover, the more the number of TiC particles, the finer the solidified austenite grains became.

The burnishing parameters were as follows: burnishing force was 500 N; specimen rotation speeds were 200, 600, and 1200 rpm; feed speed was 0.01 mm/rev; and the number of tool passes was 1.
Grain Size.
Grain size was determined by an intercept method.
The mean grain sizes, d, are also indicated.
(a) Grain size in long axis direction (b) Grain size in short axis direction Fig. 5 Variation of grain size with depth below the surface.

The work analyzes application perspectives of Ti-based alloy VT6 (Ti-6Al-4V) with an ultrafine-grained structure with different grain sizes as structural material to produce high-load machine parts.
Two states were taken for comparison 1) ultrafine-grained (UFG) one with an average grain (fragment) size of 0.5 µm; 2) microcrystalline (MC) one with an average size of α-phase grains of 5 µm.
Multiaxial loading at 750oС enabled producing a bimodal state with a UFG-MC structure consisting of a matrix with an average grain (or their fragments) size of 0.8-1.5 µm with inclusion of α-phase grains of about 5 µm.
The average grain size in this state is 1.5 µm.
However, practical application of such materials is hindered by a number of disadvantages, which are first of all reduced thermal stability, impact strength, cyclic crack resistance, increased sensitivity to stress concentrators, pore formation under cyclic loads in the zone of highest stresses (near-the-surface zone).

In this study, attempts have been made to suppress the IGF of both types by (a) controlling precipitate microstructure on grain boundaries by quench control and (b) controlling grain boundary morphology by strain induced boundary migration.
Considering that the precipitation at GBs are always preferred to the precipitation inside the grain, the two C-curves for GB and grain interior precipitations are located as illustrated in Figs. 1 (a) and (b).
Fig. 4 Number of GBs with SIBM, NSIBM, and grain sizes in L and ST directions, dL, dST, respectively, as a function of true strain (cold reduction) prior to solution treatment in 7CN.
To evaluate the degree of SIBM, number of GBs with SIBM per unit area, NSIBM, was measured, and plotted together with grain size in Fig. 4 as a function of true strain.
Comparing this graph with Fig. 4, specimens cold-rolled 11% has almost the same grain size as 0% rolled specimen, but has NSIBM (number of grains with SIBM) of about 10 mm-2, which is naturally zero in 0% specimen.

This method can be subsequently used to produce refined grains in the sub-micrometer range [2, 3].
The strain in-homogeneity is low at 120° but the strain imposed is not sufficient to produce ultrafine grains and require more number of passes to achieve the maximum strain.
The load required for the channel angle of 120° is low but the strain imparted is very low such that it requires more number of passes to achieve maximum strain
· The effective strain, effective stress and peak load increases as the number of passes increases
Using equal channel angular pressing for refining grain size.