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For SSM-forming, globular grained feedstock materials are necessary.
It also shows the contents of Sc and Zr needed to achieve a certain grain size.
The mathematical model predicts a grain size of 30µm starting from contents of 0.25% Sc and 0.25% Zr.
Due to this, and as the result of a high grain density, a globular microstructure forms.
At the grain boundaries Al2LiMg-dispersoid-accumulations were detected via EDX.

The grain size is smaller after hot rolling below Tnr compare to above Tnr.
The bainite-ferrite grain structure is more equi-axed after hot rolling above Tnr in the alloys DP6, DP8 and HSLA however, during hot rolling below Tnr shows bainite-ferrite grains elongated along the rolling direction with fine grain size.
The alloy DP8 also shows some with very fine grain size bands along the rolling direction after etching.
It can be seen that, at temperatures above the Tnr, the deformed austenite grains (containing fcc deformation textures) are regularly converted into equiaxed grains (containing the “cube” or fcc recrystallization texture.
Each of these can be expected to be responsible for a number of products.

But if the grain size is too small, the magnetic recording media may be thermal instability of magnetization.
Several researches have reported that alloying Cr additives to FePt can promote the ability of phase transformation at lower temperatures or reduce the grain size [1-4].
Kuo [1] reported that the Cr additive can decrease the saturation magnetization and coercivity of FePt and reduce the grain size during annealing process.
The grain size decreased with the doped Cr contents.
Srivastava [3] reported that there is no Cr intermetallics formed with Fe and/or Pt and the Cr additive has quite effects both on ordering temperature and grain size of FePt.

Fig. 1(a) indicates that undoped mullite powers are consisted of granular mullite grains and small short-acicular mullite grains about 0.1 μm in size when heated at 1200 ◦C for 2 h.
As shown in Fig.1(c) Fe-doped mullite powers have a smaller grain size with prismatical, granular and platy grain shapes.
The results of XRD indicate when Ti, Fe-doped mullite gels prepared by sol-gel process and sintered at above 1200 ◦C, mullite becomes the only crystallization phase, therefore, pure mullite is used as the standard in the calculation of lattice parameters(JCPDS number is 82-37 ： a=7.543Å，b= 7.692Å，c= 2.884Å；V=167.31 Å3), this calculation is processed by the software Celler, the results are displayed in Fig.2 to Fig. 5.
From the analysis of SEM micrograph and EDX spectrum, with the doping of TiO2 and Fe2O3, the grain size increased relatively and some changes had been detected in the grain shape of mullite, moreover, Fe3+ and Ti4+ had doped into the crystal lattice of mullite but unevenly.

According to the basic research on the microstructure and hardening mechanism of TWIP steel, the grain size have a notable effect on the mechanical performance.
A set of samples, which were heated to 1200°C and held for 5 min without deformation then water-cooled to room temperature, were examined by metallographic observation and showed an average grain size of 35μm.
is effected by the grain size, pre-deformation (the first compress) reduction, deformation rate and deformation temperature, and can be described as follow: (4) where A, p, q and s are constants determined by the material, Q is the static recrystallization activation energy, R is the molar gas constant and is the origin grain size at the entity of μm.
With the increase of the gap time between deformation passes, the numbers of nucleations increased and the recrystallized grain growed.
Wang, Influence of grain size on TWIP effect in a TWIP steel [J].

Microstructure Fig. 2a reveals that for Al2O3-1% Cu composite has a homogeneous microstructure with respect to the grain size.
In the case of Al2O3-5% Cu composite, it can be observed that the same characteristics of the microstructure are shown in Fig. 2b, that is, a clear gray phase that corresponds to the matrix grains is apparent, a white and brilliant phase due to the metal and dark hollows that correspond to porosity.
Another appreciably observation is the growth of both grains and pores size.
Fig. 2d shows that in Al2O3-20% Cu composite the grain in the microstructure is now bigger, the pores are larger but their number has diminished.
So mass transfer is enhanced with the copper presence, by a sintered liquid mechanism, and for this reason the grain growth in the samples with the increments in the copper content is then explained.

The morphology was studied by SEM which revealed that ZnO grows in cylindrical columnar grains, normal to the SiC surface, with a mean diameter of around 100-120 nm and lengths dependent on the film thickness, see Fig. 2.
All XRD spectra presented are shown after background subtraction with the number of counts (Intensity) on the yaxis and the detector position angle (2θ) on the x-axis.
These observations indicate that as the film is annealed, it moves from a polycrystalline structure to a single crystal structure, with columnar grains with the (002) plane oriented preferentially perpendicularly to the SiC substrate.
These ZnO films have cylindrical grains grown on an initial layer of randomly oriented crystallites.
It was found that the ZnO grows epitaxially on the substrate with larger columnar grains.

This is well understood in terms of grain boundary pinning by solute additions and second phase precipitation during the transformation sequence [3].
Similar results in a number of publications have been discussed and are referred in [7].
Moreover, it can be seen that the mean grain size of the Ni/Ni3P matrix is low compared to the size of the diamond particles.
The incorporated diamond particles are about four times larger compared to the mean matrix grain size, and therefore their contribution to the dispersion hardening of the composite is limited.
The improved hardness is a result of the preserved nano-grained microstructure of the matrix and the high fraction of reinforcing hard particles.

The samples of the titanium alloy of the submicrocrystalline structure were prepared by rolling bars with a cross section of 6´6 mm, obtained using one of the methods of an intense plastic deformation (abc-pressing) under the technology of gradual grinding of grains in the samples using the method of abc-pressing with parallel stepwise decrease in the temperature in the range of 750-500 °C.
Application of the technology of obtaining a submicrocrystalline state in the Grade 2 alloy in the process of gradual grinding of grains in the samples by abc-pressing method at a parallel stepwise decrease of the temperature in the range of 750-500 °C leads to an intensive introduction of oxygen atoms into the crystalline lattice a-Ti.
According to the published data, the weld zone and the heat-affected zone in titanium alloys have a different number of characteristic sections that reflect different limiting heating temperatures and different cooling rates [10].
The first stage may include formation of a weakly-stable metastable α-Ti phase, and the second stage may include the breakdown of this weakly-stable metastable phase into a number of metastable phases w-Ti, α¢¢-Ti and α2-Ti [9, 12].
Chemical composition in the weld zone from local areas of the titanium alloy Grade 2 in submicro- and microcrystalline states (Fig. 3) Point number O, [weight%] Fe, [weight%] Al, [weight%] Ti, [weight%] Microcrystalline state 3 - 1.81 - 98.19 4 - 1.80 - 98.20 5 - 1.33 - 98.67 6 - 1.66 - 98.34 7 - 1.33 - 98.67 Point number O, [weight%] Fe, [weight%] Al, [weight%] Ti, [weight%] 8 - 1.35 - 98.65 9 - 1.26 - 98.74 10 - 1.24 - 98.76 11 - 1.84 - 98.16 Submicrocrystalline state 1 8.74 4.47 0.39 86.39 3 8.46 5.64 0.48 85.42 2 7.88 4.98 0.53 86.61 4 11.25 3.40 0.32 85.03 5 8.12 3.41 0.33 88.13 7 7.99 4.73 0.42 86.86 8 7.49 4.06 0.44 88.01 9 7.16 6.66 0.58 85.60 Fig. 3.

Under the machined surface no plastically deformed layer or lengthening of the grains were observed.
This deformation is caused and/or accentuated by a large number of cutting parameters, cutter and workpiece (material and grain size) parameters [5].
The grains under the machined surface are deformed in the direction of cutting [12,18,19].
The test coupons were mechanically polished using sand paper with grain size decreasing from 800 to 4000 grains/mm2.
There will always be a tendency to indent on a few grains, always inevitably leading to dispersion.