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Kori et al. [5] studied the development of an efficient grain refiner for Al-7Si alloy and its modification with strontium.
For ZL101 alloy, from Fig. 2, it can be noted that the crack length generally increased with the increase in the number of thermal cycles.
Moreover, the amount of crack length increase became smaller at high number of cycles.
Moreover, grain refinement in the OA alloy could make thermal fatigue cracking appeared much later and propagated much slowly.
And the grain refinement in the OA alloy could make the thermal fatigue cracking appeared much later and propagated much slowly.

Creep-Feed Grinding(CFG) is one of the none-traditional machining in which form grinding to full depth is performed in limited number of passes.
Wheel was made of 60 US mesh AL2O3 abrasive grains.The specification of grinding wheel is displayed in Table 2.
Table 2: The specification of grinding wheel Manufacturer Type Material FEPA Grain size (mesh) Mean grain size[dg,μm] Saint Gobain 45A60E12VBEP White AL2O3 60 240-260 2.2.
Fig. 7: The average grain size of ground specimens 4.
With increasing the number of CD Passes, the surface roughness of specimens with higher cutting depth (more than 5 mm) has been better.

There are a number of factors that cause interdiffusion in thin films to be enhanced at low temperatures: (i) A high density of low temperature short circuit paths such as grain boundaries and dislocations may be operative.
Basically RBS analyses the number and energy of backscattered He+ ions at a specific angle.
The weakness of the RBS technique is its sensitivity to lighter atoms and its poor resolution for elements of similar atomic number.
The selected area diffraction pattern in the unannealed films showed more number of diffraction rings than that in the annealed films.
This is merely a statement of Fick’s first law by equating the number of atoms that reach a depth y from either grain boundary or lattice diffusion.

Then, the equivalent diameter of each single grain was used to determine both the mean grain size and their statistical distribution as shown in Fig. 1: Ti-6Al-4V shows a grain size of 6 µm, while the as-received Ti-4Al-2.5V-1.5Fe alloys has a grain size below 3 µm - this could be considered an ultrafine-grained (UFG) microstructure.
This is believed to be caused by large cluster of grains with low angle grain boundaries - those tend to remain together thus effectively acting as a much larger grain.
In the case of Ti-4Al-2.5V-1.5Fe, grain growth is observed.
Nevertheless, grain sliding is still the main deformation mechanism.
Thus, one desires a homogeneous equiaxed microstructure with weak texture and a maximum number of high-angle grain boundaries.

The harmonic structure is composed of dispersed coarse grains and fine grains that are networked around them.
The harmonic structure is heterogeneous structure in which the fine grain regions (Shell) cover the coarse grain regions (Core) and fine grain regions are interconnected in a network, as shown in Fig. 1.
Coarse Grains (Core) Fine grains (Shell) Fig. 1.
The surface region is composed of fine grains and interior region is composed of coarse grains.
Acknowledgement This work was supported by JSPS KAKENHI Grant Numbers JP24K01203 and the grant from Iketani Science and Technology Foundation (contact No. 0341231-A) and the supports are gratefully appreciated.

Previous studies have shown that grain boundaries is also the potential dislocation sources ot deformed metal, but they play only a minor role in generating new dislocations.
Based on the microscopic characteristics of plastic deformation of polycrystalline, dislocation slipping of polycrystalline occurs mainly in the grain at low temperatures or room temperature, and they can not pass through the grain boundaries and slip between grains, which has also been confirmed by experimental studies which shows that slip bands are parallel to each other at the same grain, but they are not continuous when passing through grain boundaries.
r(s,t) is assumed to be the number of new slip bands per unit length of the machined surface in unit time in the process of the machining deformation of the titanium alloy monolithic component.
The number of the new slip bands generated per unit length is r(s,t)dt in time dt, and the number of which move to the depth of h is given by: (1) The number of slip bands which are generated in the time of (0, t-h/ud) and stop at the depth of (h, h+dh) is given by: (2) In addition, the number of slip bands which are generated in the time of (t-h/ud, t-h/ud+dt) and stop at the depth of (h, h+dh) at timeis given by: (3) Consequently, the total number of slip bands which stop at the depth of (h, h+dh) in time t is given by: (4) The number of dislocations at the depth of h beneath the machined surface of the titanium alloy monolithic component which is approximately calculated with the quantitative expressions of edge dislocations per unit length in Dislocation Pile-up Group is given by: (5) Therefore,
TC4 that consists of a-Ti of HCP accounting for 90% and b-Ti distributed at the grain boundaries is the (a+b) two-phase titanium alloy.

The grain size is uniform, and the grain size is about 1~4μm.
The reason may be that ZYK530 alloy undergoes two large high temperature plastic deformation, during which the grains are crushed, not only a large number of dispersed phases are formed, but also a small number of Z-Mg12ZnY phases, a small number of Mg-Zn phases and undetermined phases are observed in addition to I-Mg3Zn6Y and W-Mg3Y2Zn3 phases.
Compared with the as-forged ZYK530 alloy, the grain size refinement is not obvious.
The dimples of T5 alloy are obviously smaller and more than those of T6 alloy, and the number of precipitates of T5 alloy is also significantly more than that of T6 alloy.
Because there are few slip systems in Mg, the strains on both sides of grain boundary are inconsistent during tensile deformation at room temperature, and many slips often occur in the adjacent areas of grain boundary, forming the influence zone of grain boundary[16].

The paper describes the recent improvements (spatial and the temporal resolution, grain imaging).
Grain imaging Phase or attenuation contrast in X-ray imaging are extremely weak between two adjacent aluminum grains.
Three-dimensional analysis of eutectic grains in hypoeutectic Al-Si alloys.
Discontinuous penetration of liquid Ga into grain boundaries of Al polycrystals.
Recrystallization kinetics of individual bulk grains in 90% cold-rolled aluminum.

Figure 3.a and 3.b show the size of a small grain (fine) to a larger size (coarse), then from Figure 3.b to Figure 3.c and 3.d, show that the grain size becomes smaller (fine).
However, in Figure 3.c and 3.d, show that the grain size becomes smaller (fine).
However, in Figure 3.c and 3.d seen that the more refined the size be accompanied the number of phase d1 resulted in decreased the alloy hardness, otherwise if the grain size more finer and the number of phase increased so increased the hardness alloys.
The addition of alloying elements will result in the increase of grain and phase d1, because the element that was added constitute beginning of the formation of the grain core, and on futher heating of cores then the core will turn into grains.
The results of microstructure examination shows that the addition of Zr will form finer grain and increase the amount of d1 phase that has been formed.

Applied production method allowed to obtain dense sinters with fine grain size resulted from large shear strains.
The light microscopy was applied to estimate average powders particles and sinters grains size.
The processing temperature had large influence on grain growth as well as the mechanical properties of sinters.
The inverse method calculations allowed to prepare the plot which presents the changes of the crack length versus the growth of cycles number (see Fig 3a).
It is clearly visible that crack growth rate is higher for P series samples where similar to D series crack length growth was observed after significantly lower cycles number increase.