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.% Ca addition, the phase of Al2Y is refined obviously and the phase of Mg17Al12 has a dramatic decrease in number.
It can be observed that the Mg17Al12 phase is distributed in the grain interior and on the grain boundaries and that the second phase Al2Y is diffused in the intragranular [7].
After T6 treatment, blocky Mg17Al12 is discontinuously distributed at the grain boundaries and punctate Al2Y phase is unevenly distributed, mainly in grain.
Those are illustrated on the two respects: the grain growth is suppressed and the generation number of β(Mg17Al12) can be reduced, and the second phase particles are dispersed in the alloy.
It is well known that large numbers of β(Mg17Al12) phases can barely promote the high temperature mechanical properties of Mg-5.5Al-1.2Y alloy.

The numbering of the variants is proposed, as well as the misorientations between them.
Conversely, a method for calculating the parent hcp orientation from a sufficient number of inherited variants is proposed.
This limited number is due to the properties of the inverse orientation relation 1 g−∆ and the rotational symmetry elements of the hcp and tetragonal group.
Under this circumstance, a new analysis of the orientation relations and variant numbering must be made.
Lamellar colonies and Widmanstätten laths co-exist in a given grain.

The finer-grained copper was able to outperform (by between 4- to 16-fold) its coarser-grained counterpart under severe test conditions, but no advantage was observed when conditions were milder.
At such fine grain sizes, the volume of the material influenced by proximity to a grain boundary becomes significant [1-3].
In the present study, elemental copper powder, with average as-received grain size of 156 nm, was mechanically milled for 10 hr, reducing the grain size to about 25 nm.
There is also a marked difference between the degree of oxidation observed on the finer-grained and coarser-grained copper: the oxide on the former is more extensive, while that on the latter is sparse and patchy.
The greater number of reactive grain boundaries in the finer-grained 63 nm copper promotes oxidation, and the rate of formation of the oxide layer.

As the deformation rate decrease, the lamellar organization in the titanium alloy will convert into the equiaxed grains.
When the sample was compressed for 5.6mm, a few equiaxed grains occurred.
When the sample was compressed for 7mm, a large number of equiaxed grain occurred.
When the sample was compressed for 7mm, a large number of equiaxed grain occurred, this is because that the deformation of powder particles was so sufficient that distortion energy had been produced a great deal, which made dynamic recrystallization carry out completely.
Further compression up to 7mm, a large number of equiaxed grain occurred.

A stochastic nucleation model is established to calculate the nucleus number as follows: (3) Where N is the nucleus density, ΔT is the undercooling, Ns is the maximum nucleus density, ΔTσ is the standard deviation of the distribution, and ΔTN is the average nucleation undercooling.
The grain growth is based on the KGT equation [18], and the growth speed of the grain tip is described as follows: (5) Where α and β are the coefficients.
Previous studies [11, 15] showed that a concave shaped mushy zone might make the grain convergent, and a convex shaped mushy zone makes the grain divergent.
There are some broken grain in the exhaust edge of the blade.
The grain grew very well in the back side of the blade, and some stray grain nucleate in the listrium of the blade.

Therefore, many research focused on the size effect in metla forming of mini parts and it can be characterized by volume grain size, surface grain size and grain size to thickness size effect [3].
Material and methods The spur gear specifications are shown in Table 1, In order to evaluate the effect of annealing treatment on grain size resulting in varying deformability of the commercial pure titanium (grade 2, CP2), a mini gear with an outside diameter (2*R0) of 9.2 mm, number of teeth (N = 8), and face width (h) of 5 mm, was proposed as shown in Fig. 1.
Specification of spur gear dies Parameters Value Number of teeth 8 Module 0.92 Pressure angle(˚) 20 Pitch diameter (mm) 7.36 Addendum circle (mm) 9.2 Dedendum circle (mm) 5.06 Face width (mm) 5 Modification coefficient 0 Fig. 1.
Fig. 3 (c) reveals that grain forms when AT is 700°C and the average α-phase grain size is 96.7µm.
Therefore, the average grain size for the specimen that contains β-phase grain is not calculated.

A large number of fine secondary-NiOss particles were separated from the CaOss crystal grains in CaO-NiO solid solution and improved the hydration resistance.
Once the sintered compacts are processed into grains of < 1 mm for the use to the nozzle as the raw material, the grains will be hydrated.
The microstructure of the sintered compacts is shown in Fig.9(a), which consists of white grains and a dark matrix.
EPMA analysis indicated that the white grains are a NiO rich solid solution (primary-NiOss) containing around 7 mol% of CaO.
A large number of fine particles (< 0.3 µm) were found to uniformly distribute in the matrix.

The two plate surfaces including the faying edges were thoroughly cleaned from and oxides and dirt using silicon carbide paper with grit number 800 in order to avoid their intrusion in the weld nugget while welding.
The reason to this softening is referred to the increase of weld nugget grain size.
The coarse grain size not only softens the structure but also increases its ductility.
Higher ratios lead to higher degree of deformation and consequently finer grain size.
Acknowledgment The authors would like express their sincere thanks to SABIC- Saudi Arabia for financing this work, grant number 427/30.

Austenite grain size about 1µm was reported.
These two phenomena are directly controlled by the number of nucleation sites.
Additionally, it was observed that coarse-grained IF steel (IF1) was deformed inhomogeneously while fine-grained specimens have been deformed smoothly.
Typical IF steel represents coarse-grained structure.
Weng (Ed.), Ultra-Fine Grained Steels.

The number of turns n was equal to 0.25 and 5.
Diffraction patterns of the NS MEA TWIP obtained by RT-HPT (a) and cryo-HPT (b), the number of rotations n = 5 [23].
Diffraction patterns of the NS MEA TRIP obtained by RT-HPT (a) and cryo-HPT (b), the number of rotations n = 5 [23].
The observed loss of plasticity is obviously associated with an increase in the proportion of grain boundaries in the nanostructured state and the impossibility of transferring plasticity from grain to grain.
Acoustic Properties of MEA TRIP and MEA TWIP in the Coarse-Grained State Fig. 7.