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The amount of deformation bands seems to increase with the number of ECAP passes, and their distribution becomes more homogeneous.
The initial grain boundaries are still distinguishable, however, the original grains become heavily deformed indicating the greater degree of grain refinement.
Sub-grain boundaries evolve within the grains/crystallite structure.
The quantity of these deformation bands increases with number of ECAP passes increasing degree of grain refinement. 2.
The increased dislocation density and a large number of grain boundaries allow faster diffusion.

The grain sizes were measured by the Digital Micrograph.
This is because, during the solid-state phase change of Ti6Al4V alloy, the increased grain boundary length for finer grains leads to the increasing o f the α phase nucleating number.
(b) A number of researches have discovered that, in tensile test, dislocation glide in microstructure with fine grain is hindered by grain boundary resulting in deformation strengthening.
Meanwhile, stress concentration in grain boundary can also be released through intercoordination among grain boundaries for fine grain, which can inhibit the crack to nucleate and grow leading to uniform plastic deformation and the improved plasticity due to the finer grain size.
(a) (c) Fig.3 Relationships between tensile properties and grain size of Ti-6Al-4V alloy castings (a) tensile strength vs grain size (b) yield strength vs grain size (c) elongation percentage vs grain size Conclusion In the centrifugal field, the finer the microstructure, the higher the mechanical property for Ti-6Al-4V alloy castings.

Because of the plastic bond, the number of active abrasives will increase and the abrasive cutting depth will become even and small [1].
Simulation results showed the number of point regions in the minimal cutting depth decreased to zero rapidly.
But detection results showed that the number of point increased in the minimal cutting depth range.
The number of point regions in zero cutting depth was most (4500 Pts).
The number of these fine grains will decrease to zero with the grit size decreasing, so the point regions in minimal cutting depth dropped to zero in simulation.

Fracture of ceramic materials mainly results from nucleation and expansion of large number of micro-cracks from interior.
The vibration cycle of grain is shown in Fig. 2.
has relations with the contact point of grains and workpiece.
When the grains do not contact with the workpiece, equals zero; when the grains do not depart from the workpiece, equals T1/2.
Then, the number of dynamic effective particles is (8) Fig.3 The grinding force of single particle , (9) where, lg is the length of contact arc, and ; is wheel width; K0 is a coefficient related to particle shape, dressing conditions and other; vg is the concentration of grains; d0 is the average diameter of grains.

During secondary recrystallisation abnormal grain growth of Goss-oriented grains takes places while normal grain growth is inhibited by particles.
Journal Title and Volume Number (to be inserted by the publisher) 3 exceeding 10°/µm.
A rough estimate of the number of Goss-oriented grains per volume in the deformed as well as in the annealed material shows that about 1 of 12 grains that are left over in the highly deformed material grows during recrystallisation.
Journal Title and Volume Number (to be inserted by the publisher) 5 and the γ-fibre components.
Nucleation of Goss grains.

We consider mono-phase grains illuminated by a beam smaller than the grain size.
The grain with the maximum value of N/M among the candidate grains was selected as the grain that occupies Q, where N is the number of detected diffraction spots from a grain and M is a normalization factor correcting orientation dependence of N.
From the orientation image, the orientation distribution in each grain and the mean grain size were estimated to be uniform and ∼ 60 µm.
To evaluate crystallographic rotation of each grain, typical coarse grains, G1-G7, were selected as shown in Figs. 3(e)-(k).
This work was supported by JSPS KAKENHI Grant Number 22760571.

By microcosmic orientation distribution analyse find that the new {011}<100> grains are nucleated within shear bands in the deformed {111}<112> grains, New {111}<112> grains are nucleated within deformed {111}<110> grains and new {111}<110> grains originated in the deformed {111}<112> grains .
Some grains are smooth and lightly etched whereas other grains are darkly etched.
The number and the size of the recrystallized grains generally increase as the annealing temperature increases.
It is observed that some deformed grains are completely consumed by new grains, whereas other deformed grains are partially replaced by new grains or even remain recovered without any nucleation.
Here, blue grain represent {111}<112>, green grain {111}<110> , sky blue grain {011}<100>.

The erbium content was optimized by measurement of grain refining effects and tensile strength.
Previous study [3] suggests that the modification ability of an element may be the result of a certain combination of the valence electron charge number, the atom number, and the atomic radius of the modifier.
In addition, grain size tends to become bigger than the grain size with the solution temperature of 595°C in Fig. 5(d).
Table 5 The tensile property of two specimens Number σb (MPa) σs (MPa) δ (%) 3#-5 335.98 330.52 3.3 3#-7 367.20 350.44 5.0 Conclusions 1.
Grain refinement mechanism in an Al-Si-Mg alloy with scandium.

Numerous reports are now available describing the application of HPT to a range of pure metals and simple alloys and excellent grain refinement were achieved using this process with the average grain size often reduced to the nanoscale range.
Inspections of Fig. 1 show several trends describing the hardness evolution through increasing numbers of HPT revolutions.
The higher values of Hv in the central region tend to decrease with increasing numbers of turns.
Close inspection shows these central regions of higher hardness extend through decreasing areas with increasing number of turns.
Third, there is a decrease in the hardness values over the disks when processing is continued to larger numbers of turns.

Another approach is to produce ultrafine-grained alloys as it has been long known from Hall-Petch relation [1, 2] by metallurgist that smaller grain size gives higher strength.
A high level of misorientation occurs and finally sub-grain boundaries and high-angle grain boundaries can be formed that gives rise to ultrafine grains.
In this study, 6061 aluminium alloy was ECAPed using route Bc with different number of passes.
The sample was subjected to an equivalent strain of 0.89 (calculated from Eq. 1 [5]) for 1 pass and increasing with number of passes i.e. 1.43, 2.14, and 2.85 for 2, 3, and 4 passes respectively
The distribution of different grain sizes in the 4-pass sample was demonstrated in Figure 6 and that the average grain size was at 2.23 µm and this was in fine-grain regime.