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The results show that moderate addition of Y and Gd to AZ61 magnesium alloy can obviously refine grains of AZ61 alloy, and decrease the amount of Mg17Al12 phase.
The high-temperature phases precipitate at grain boundaries to the pinning effect on grain boundary and prevent further grain growth, thereby significantly refine the grain.
When the content of Y and Gd is up to 2.7%, the grain is most refined, Y3Al2 and Al2Gd3 phases small precipitation on the grain boundary and in the crystal.
When the content of Y and Gd is more than 2.7%, the number of blocky Y3Al2 and Al2Gd3 phases increased, as well as sizes.
According to Hall-Petch law[6], grain refinement can significantly increase the yield strength of magnesium alloy.

The average grain size dramatically decreased from 115 μm to 70 μm with applying EMS.
Various colors in the photograph show different orientation of grains.
Fig. 6 Average grain size distribution.
A large number of small grains sedimented and flowed under the control of natural and then forced convections, eventually accumulated in the bottom area of the sump.
Those small grains may attribute to the negative segregation.

Journal Title and Volume Number (to be inserted by the publisher) 3 {223}<582>) has yet to be fully explained.
Recrystallization in alpha fibre oriented grains is slowed, partially, due to the low misorientation between subgrains and thus, low stored energy, within grains of these orientations.
Here, the unrecrystallized alpha fibre grains, based on the previous discussion, are taken to have a lower flow stress compared to the unrecrystallized gamma fibre grains.
The nonlinear relationship between recrystallized fraction and flow stress is thus attributable to the initial loss of the 'stronger' deformed gamma fibre grains in place of the 'softer' alpha fibre grains.
Taylor simulations have been performed using the bulk textures measured by x-ray diffraction (figure 3) in Journal Title and Volume Number (to be inserted by the publisher) 5 order to simulate the experimental r-values.

AghaAli et al. [6] mentioned that grain size number in HAZ is increased corresponded to the number of weld repair that had done on the same location as shown in Fig. 2.
Yet, subsequent heat input due to repeated weld repair will facilitate grain growth and therefore grain size number is decreased.
On the other hand, Vega et al. [9] stated that grain growth is observable in coarse grain HAZ corresponding to the number of repair welding.
Fig. 2 Interrelation between ASTM grain size number in HAZ and number of weld repair [6].
This is because in the first repair new grain is generated and grain refinement is observed, but those grains are started to growth in the following weld repair.

Introduction Rotary kiln has been widely used in chemical engineering and mechanical engineering to process materials such as mixing of solids, drying grain, and coating of materials, clacination of cement, pyrolysis of oil shale, hazardous waste and oil sand.
Number of contacts between large and small particles in axial direction.
From Figure 4 we can see that number of contacts in the central region is lager.
The change of time-averaged number of contacts in axial direction From Figure 5 we can obtain that number contacts gradually decrease from the central region to both sides.
Taberlet, “Recent advances in DEM simulations of grains in a rotating drum,” Soft Matter, vol. 4, 2008, pp. 1345-1348, doi:10.1039/b71729c

Materials Performance of HRBF500 Grain Reinforcing Bar.
Fine grain steel, through the refinement of the grain boundary dislocation, refinement of blocked, the strength of steel enhanced.
Grain refinement with the most significant and effect in steel, increasing strength and toughness [4].
At present, our country has smelting, rolling weathering steel and 800MPa ultra-fine grained steel, and using Q235 steel make industrial experiment, producing 630MPa tensile strength and yield strength of 500 ~ 650MPa of fine grain steel successfully.
the role of the number usually only once, load value is particularly large, but uncertain.

After the deformation, the lines were still well-visible and changed their relative orientation according to the number of turns (e.g. they kept their relative orientation for an integer number of turns).
Grain refinement is no major effect of the deformation process since the grain size is still in the order of magnitude of microns.
The APB causes local disorder, so a large number of APB reduces the degree of order significantly.
One difference to our experiments is, apart from the different SPD method, the grain size of the initial material.
Due to melt spinning prior to ball milling, their initial grain size was about 80nm, while our grains were several microns large.

La2O3 doping promotes crystal grain growth, CeO2 doping makes grain crystal size uniform, changes tetragonal into granular structure and restrains crystal grain growth.
The doping of La2O3 can promote grain growth.
Compared to samples doped with 0.5 wt.% CeO2, the number of large size grains reduced, the size of grain tends to mean in samples when without CeO2 doping.
From the view of grain shape, the number of square shaped grain decreased, while granular grain increased, therefore the growth of grain was restricted when CeO2 doped.
The growth of the grain is promoted when La2O3 doped; the crystal grain size tends to average and the view of grain turns to granular from square shaped when CeO2 doped.

Rotation of grains leads to emergence of high local internal stresses.
Rotation of grains leads to emergence of high local internal stresses (fig.3).
So, high chemical activity of gallium turns this technological task into a sufficiently complicated process which depends on the number of both positive and negative factors.
Mass transfer of gallium into Al alloy between grain (SEM).
The diffusion results in an intense growth of grains sizes and volume of the detail, in shifting of old grain boundaries and formation of new ones.

(4) where R is dendrite tip radius, Γ is Gibbs-Thomson coefficient, Pei is Peclet number, mi is liquid slope,C0,i is initial concentration, ki is partition coefficient, ζc(Pei) is function of Peclet number, Iv(Pei) is Ivantsov solution (where subscript i=Cr or Al), Ghkl is temperature gradient along the crystallographic orientation.
Three typical weld defects, severe stray grain formation, centerline grain boundary formation and asymmetrical solidification cracking, are simultaneously mitigated to improve weld quality.
Stray grain formation in welds of Ni-based superalloy CMSX-4.
Stray grain formation in single crystal Ni-based superalloy welds.
Analysis of stray grain formation in single-crystal nickel-based superalloy welds.