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Magnesium alloys have less slip systems, so the residual grain boundary dislocations will have greatest Burger vector and in the grain boundary the strain level is very high.
At first, the grain boundary cracks appear at the convex part of grain boundary and at the junction of the reinforcing phase/matrix.
As the grain boundary sliding, the cracks gradually extend to the cavity.
When Nd is added to the alloy, alloy is gradually from dendrite structure to equiaxed grain structure, and the grains become fine.
While the number of Mg17Al12 phase is reducing, the high melting point phase of Al-Nd phase is precipitating.

Using brazed CBN grinding wheel, grains can be combined with wheel matrix in high bonding strength, which is helpful to minimize wheel wear and to gain a good grinding ability.
It also requires good thermal conductivity grains and no material defect wheel matrix.
Making the bonding strength higher enough, the grains' protrusion height can reach 50% which makes the wheel with a perfect and sharp topography.
So the number of effective grains is increased, which slows down wheel wear and the grinding force.
With the stress function rF rt , defining the thickness variation as t Cr   , a stress differential equation of variable thickness wheel is     2 2 2 3 2 1 1 (3 ) 0 d F dF r r F Cr dr dr              (5) where C is constant and  is an arbitrary positive number.

The formation of premature fine pores at the grain boundary in the weld with PWHT at 704 o C accounted for the intergranular dimple fracture of the specimen.
The fracture appearance of the as-welded (AW) and the 482 oC-aged (W-482) welds comprised of mainly transgranular dimple and increased the extent of grain boundary shear at elevated temperature.
To distinguish the specimens with the PWHT at various temperatures, the numbers 482 and 704 were attached to the specimens, e.g., W-482 specimen represented the weldwith PWHT at 482°C for 3 hr.
Extremely fine and shallow dimples were also found in the W-482 specimen, whereas, TG dimples mixed with grain boundary shear fracture was for the W-704 specimen at room temperature (Fig. 4(c)).
At 450 oC, coarse TG dimples mixed with increased extent of grain boundary shears were seen in AW and W-482 specimens.

Modified layers characterized by the gradient structure and consist of dendritic grains and a eutectic located at the grain boundaries.
Fabrication of the coatings was accompanied by crystallization processes and the formation of the dendritic structure consisting of γ-solid solution grains and a eutectic located at the grain boundaries (Fig. 1).
The X-ray diffraction analysis revealed that dendritic grains were represented by the γ-solid solution based on Ni and Fe.
Increasing a cladding velocity resulted in decreasing the number of dendritic crystals which possessed a low hardness and strength level.

These mechanisms lead to the substantial microstructural modification of the feedstock, resulting in fine, equiaxed grains [8].
The microstructure of the as-received AA6060 T6 feedstock is shown in Fig. 4-b, exhibiting large equiaxed grains with an approximate average grain size of 40 μm.
Notably, the topmost layers show a tendency for higher hardness values, which can be attributed to the limited number of thermal cycles experienced by these layers.
The microstructure of the builds exhibited more equiaxed and finer grains compared to as-received AA6060 T6 feedstock.
Zhai, Significant strengthening effect in ultra-fine grained Al alloy made by fast solidification and hot extrusion processes, J. of Mat.

The obtained results indicate that the finer the grain size of the grinding wheel, the greater the improvement in the surface roughness.
This is attributed to changes in the material removal mechanism between the two grains.
The surfaces ground with the #325 wheels demonstrate a rough processed state with the material removed by the breakdown of the grain boundary.
On the surface ground with the #1200 wheel, a small number of areas in which the material was removed by means other than the breakdown of the grain boundary were confirmed.
Figure 12 shows the relationship between the frictional coefficient µ and the number of sliding cycles, with respect to the results of the friction and wear testing.

The average particle size and the average grain size of the PBT increased with the increase of PbO.
The average grain size and average particle size of the sample were determined using the linear interception method.
Shows XRD patterns of PBT powders made from starting mixtures containing different levels of PbO, which could be matched with the JCPDS file number 060452 [6].
The average grain size first decreased with excess PbO and reach its minimum at 3 wt.%.
Percent perovskite phase, c/a ratio, average particle size, average grain size, density and shrinkage of PBT calcined powders and sintered ceramics Summary The crystal structure of PBT calcined powders and sintered ceramics is tetragonal perovskite.

A large number of commercial product based on NHL binders are distributed in the market for several uses and their application is increasing.
A high amount of fine grained calcite is present as carbonatic filler.
C2S is the main hydraulic phase traceable in the binder matrix of mortar MC, but few C3S grains are present as well.
MD has a compact binder with only few C2S grains dispersed in the matrix.
Both binders show predominant C2S and few partially reacted C3S grains in the hardened mortars.

The grain size is a few hundred angstroms.
In this work, the average grain size is about 13.4 nm .
The surface topography of the as-deposited layer is not uniform and the grain size is a few hundred angstroms.
The small grains on the surface of CuInSi nanocomposite film could be seen.
The grain size is a few hundred angstroms.

This clearly illustrates that a partial reversion of the strain produces a net Journal Title and Volume Number (to be inserted by the publisher) 3 retardation of the static recrystallization.
Journal Title and Volume Number (to be inserted by the publisher) 5 Alternatively, the orientation spread average, OSA, has been used, which represents the mean value of the misorientation between any two points belonging to the same grain.
This parameter provides a picture of the in-grain curvature developed during the deformation.
However, other grains exhibiting some in-grain banding, see Fig. 4.c, develop important misorientations.
Conf. on "Recrystallization and Grain Growth", Eds.