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Mechanical twining was observed in ~90% grains while the grains were not significantly refined (~10 μm) after ECAP.
This yield strength is much higher than 620-640 MPa, the yield strength of ultrafine-grained titanium by 8~12 passes of ECAP at 450 oC with a grain size of 200-300 nm, and is close to ~ 790 MPa, the yield strength of commercial Ti-6Al-4V alloys.
Experimental Parameters The experiments were performed using annealed rolled bars of CP titanium (G2) with an average grain size of ~10 μm.
The mechanical properties of CP titanium are listed in Table 1 where the upper row is for the initial unpressed material (as-annealed state), the second to fifth rows are for specimens pressed after ECAP with a die angle of 135o, where T and N denote the absolute temperature of pressing and the number of ECAP passes, respectively.
It is clearly shown that the initial structure was composed of nearly equiaxed grains with an average size of ~10 μm, while the deformed microstructures after ECAP are elongated and those grains lie along a direction inclined to the longitudinal direction (horizontal).

In consideration of the significantly increased number density of oxide particles with high shearing [7, 13], the melt conditioning in the sump during DC casting provides a unique condition for grain refinement with low temperature gradient and high growth velocity [11].
In the case of DC casting with chemical grain refiner additions, the grain structure is more or less similar to granular/rosette grain structure (Fig. 1c), whilst it is more like fine equiaxed dendritic grain in the case of MC-DC casting (Fig. 1d).
Microstructures show fine grain structures in both (a) DC-GR casting; and (b) MC-DC casting; different grain morphology in (c) granular/rosette grains in DC-GR casting; and (d) fine equiaxed dendritic grains in MC-DC casting.
Grain morphology Granular/rosettes Equiaxed dendrites Ref.
In the present study, due to the different grain refining mechanisms compared to the usual chemical grain refiner scheme, the grain structure development in MC-DC is quite different (Figs.1c and 1d, Table 2).

Statistic generalized moment can be calculated in accordance with Thomas-Fermi statistic theory as follows [3]: ( )ηsϕ r eZ m = , (6) where e is elementary charge, Z is atomic number or number of electrons in the neutral atom, r is Goldschmidt's atomic radius (for FCC coordination number), and ( ) . .
Thus inoculants provide the formation of an equiaxed grain matrix, while surface-active elements favour the formation of a fine columnar grain structure.
The both matrix grain refinement and transition of grain morphology from the equiaxed to columnar one can be explained taking into account that when solidification starts, the surface-active elements segregating to liquid/solid interface significantly slow down dendrite growth, first of all in a direction along certain crystallographic planes of growing crystals that finally results in the fine structure with columnar matrix grains.
The coarse carboboride network over the matrix grains and high number of non-metallic inclusions in the case of boron [10] results in very brittle fracture mode of the HSS.
Summary Additions of inoculants particles and surface-active elements into the melt produce in HSS of M2 and T30 types structural changes concerning both the matrix and the eutectic constituent, simultaneously affecting the shape of the matrix grains and the morphology, number and distribution pattern of the eutectic carbides.

There is a large number of SiC crystalline phase appears in depth of 2200mm.
In the tap-hole clay of 2600mm～2800mm depth, elongated rod-likeβ-Si3N4 grains obviously increase while the SiC grains decrease.
A large number of high-temperature flocculent mullite phase appears and the high-temperature strength of the tap-hole clay is strengthened.
A large number of SiC is produced at the temperature of 1400 ºC.
The combination of columnarβ-Si3N4 grain and high temperature mullite is formed in this area, which improves the high-temperature strength.

Colony size or grain size is about 25 mm.
As shown in Fig. 3 (a) and (b), massive γ grains formed from α grain boundary. (0001) plane and <110> direction of a grain (1) and {111} plane and <110> direction of massive γ grain (2) (here the g grain is analyzed as fcc crystal) were indicated in the stereographic projection shown in Fig. 3 (c).
It is confirmed that (0001) plane of α grain was parallel to {111} plane of massive γ grain and <110> direction was parallel to <110> direction.
Massive γ grain initially forms at α grain boundary satisfying Blackburn orientation relationship. 3.
Financial support from the project of Czech Science Foundation under number 13-35890S is also acknowledged.

After annealing at 7500C, the dark areas almost disappeared and there were predominantly elongated coarse grains and some clusters of granular grains embedded along the boundaries of coarse grains, as shown in Fig.2 b.
During the warm forging, high dense twins and dislocations arisen in some coarse grains with preferential orientations, dividing them into a number of sub-grains or very small grains.
When re-heated to 7500C, all the originally fine broken grains in the dark areas were almost replaced by coarse elongated grains and embedded granular grains.
For the as-forged samples, the dislocation networks were significantly increased, forming a number of dense dislocation substructures called highly dense dislocation walls (HDDWs), as shown by Fig.7a.
As is well known, when the misorientation angle of grains is in the range of 0–3°, 3–15°, 60° and other, the defects are dislocations, small angle grain boundaries (SAGBs), special angle grain boundaries of twins called as ∑3 and large angle grain boundaries (LAGBs), respectively [8].

The analysis of pure polycrystalline copper has been focused on the influence of local lattice reorientations within particular grains on slip propagation across grain boundaries.
Slip propagation across the grain boundaries in polycrystalline aggregates.
This was clearly visible within the grains lying inside the MSB.
In all analyzed grains a strong tendency to grain subdivision and strain-induced reorientation was observed.
Figure 5 shows a number of layers of adjacent elongated grains penetrated by bands of strongly localized strain.

Super steel has the same chemical composition as plain carbon steel, but its yield strength is higher than plain carbon steel because it has finer grain size.
Introduction Super steel has the same chemical composition as plain carbon steel, but its yield strength is higher than plain carbon steel because it has fine grain size.
Its bending property is very good because of its high purity, fine grain, and few inclusions.
Fig. 3 Microstructures of sheets (a) vertical section，(b) transverse section In the process of rolling, the extension is far greater than the expansion, which causes the elongation of the grain in rolling direction, and enlarges the grain size in vertical section.
At the same time, the crystal orientation of grain appears regularity (i.e. creates a texture).

The results show that coarse the as-cast GWZ540 alloy consisted of α-Mg grain and two second phases, disc-like Mg5(Zn0.2Y0.2Gd0.6) and block-shaped Mg24(Y0.6Gd0.4)5.
The as-cast microstructure of the alloy consists of coarser α-Mg solid solution grain and a number of parallel dispersed disc-like second phases, typically less than 10 μm in length and 1 nm in width, as shown in Fig. 1a.
The extruded microstructure of the alloy, however, consists of fine dynamically recrystallized α-Mg solid solution grains of average size less than 5 μm (see Fig. 1b), and small particles of second phases which are distributed at the α-Mg grain boundaries.
Summary The phase composition of GWZ540 alloy consists of α-Mg solid solution grains, a disc-like phase Mg5(Zn0.2Y0.2Gd0.6) and a block-shaped phase Mg24(Y0.6Gd0.4)5.
Hot extrusion resulted in significant refinement of the α-Mg grains and second phases.

With the increasing of the strain rate, the grain size of the ferrite decreases and its distribution is uneven, and the grain boundaries increases.
Although there is no change on microstructure in the new generation of the high strength low alloy steel, by adding micro-alloy elements the grain is refined and diffused, and strenght, weldability and yield ratio are increased.
Fig.1 Tensile Semple Table 1 Experimental Strain Rate Serial number 1 2 3 4 Strain rate (s-1) 1×10-3 5 50 200 The stress-strain cueves of HC340LA with different strain rate are shown in Fig.2, and the elongation and tensile strength of HC340LA with different strain rate are shown in table 2.
The strsin rate has the influence on the grain size.
With the increasing of the strsin rate, the grain size of the ferrite decreases and its distribution is uneven, and the grain boundaries increases.