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Meanwhile, undissolved ferrite inhibits grain growth.
The number of M-A islands is small after intercritical quenching and tempering, and distribute uniformly like small dots in grains, as shown in Fig.2(a) and Fig.2(b).
The M-A islands (marked by red circles) distribute in the boundary of grains by in the shape of point-liner or gather among the grains.
The M-A island is harder phase, and the larger the number of M-A islands is, the higher the strength of the steel becomes.
After quenching, the grains are very fine.

In grains, deformation twins ({111}/<112> type) were often observed.
Finely dispersed precipitates were observed within grains.
Although the growth of grains took place during aging, fine grains were well retained even after prolonged aging at 320°C.
In-grain precipitates were not essentially observed, but a small number of coarse precipitates existed on grain boundaries, indicated by the arrows in Fig. 5.
A higher dislocation density in the HPT specimens may result in a higher number density of the G.P. zones than those of non-deformed and cold-rolled specimens.

This type of technology is based on the effect of adhesive friction between the rotating tool and the workpiece material, which has been well studied in a number of papers.
In the process of embedding into the surface of the tool blanks and conducting the process of friction stir welding a number of processes of plastic deformation, fragmentation and material flow along the tool contour take place [6].
In the stirring zone the material is mainly represented by submicrocrystalline equiaxial recrystallized grains.
In the channel, the zones of fine-grained structure and deformed structure alternate in layers and are rather heterogeneous.
The distribution of areas with different grain sizes in the structure is less heterogeneous.

Introduction The application of severe plastic deformation (SPD) to coarse-grained metals has now become a valuable procedure for fabrication of bulk solids with submicrometer or nanometer grain sizes.
This corresponds to a change of the mean size of α-Al grains and Al–Si eutectic structures, in which the alloys with small grain sizes obtained a small wear volume.
The results showed that the coefficient of friction remained unchanged after processing by ECAP, but the mass loss increased with increasing numbers of ECAP passes although the avrage grain size was reduced from 44 mm in the as-received condition to 1.3 mm after 8 passes of ECAP.
The results showed the wear volume decreased with the number of ECAP passes due to strengthening by grain refinement.
Strain-induced grain coalescence was postulated as the cause of the low wear resistance.

However, low ductility resulting from the limited number of independent slip systems in hexagonal close-packed (HCP) structure limits the use of the magnesium alloys.
However, the as-rolled AZ31 plate had an average grain size of 15.1 µm with many fine grains.
The grain size controlling factor and DRX mechanism need to be elucidated to understand the relationship of process parameter and grain size.
In this case, FSP produced a fine-grained supersaturated solution.
FSP fine-grained magnesium alloys exhibited good superplasticity.

Green carborundum abrasive grain with grit number #800 was selected by the consideration of the balance between surface roughness and removal rate.
If all abrasive grains have sphere shape with diameter in a 20 µm and uniformly arranging on the machining surface, the applied load on one abrasive grain can be calculated as over 200 mN when the lapping pressure is 61.6 kPa with the general slurry density (5 wt%).
This change of groove pattern could decrease the slurry density because of an increase in the number of groove which is source of abrasive grains.
A cup type metal-bonded diamond wheel with grit number #200 was used.
Conclusion After the deformation characteristics of SiC single crystal had been clarified by nano-indenter, the lapping using green carborundum abrasive grains with grit number #800 and the constant pressure grinding using metal-bonded diamond wheel with grit number #200 were experimented, and conclusions were as follows

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.

Introduction As the demand for cost reduction of titanium alloys increases, a considerable number of studies have recently been made on design of low cost titanium alloy.
) Si Content (wt.%) colony size grain size Thickness of a platelets (?
Journal Title and Volume Number (to be inserted by the publisher) The tensile properties of Ti-6Al-4Fe-xSi alloy at room temperature and elevated temperature are shown in Fig. 4.
As the silicon was added to the Ti-Al-Fe-Si system alloys, the grain size became refined.
Journal Title and Volume Number (to be inserted by the publisher) 1229

It is found that many recrystallized grains are formed from {111}<123> deformed grains at the beginning of recrystallization.
Recrystallization was observed to be initiated at both grain boundaries and within grains, although it was observed that recrystallized grains initiating within grains grew faster than those formed on grain boundaries.
Half of the recrystallized grains form from {111}<123> deformed grains and a quarter of recrystallized grains also have {111}<123> orientations.
Deformed grain texture Recrystallized grain texture Number Fraction [%] → {111}<123> 7 17.5 → {111}<110> 8 20 → {111}<121> 2 5 {111}<123> → Other Orientations 6 15 {111}<121> → {111}<123> 1 2.5 → {111}<110> 1 2.5 → {111}<121> 1 2.5 → {111}<123> 2 5 {111}<110> → {111}<121> 1 2.5 → {111}<123> 1 2.5 {110}<110> → {111}<110> 1 2.5 → {111}<123> 3 7.5 → {110}<110> 1 2.5 {112}<110> → {112}<110> 1 2.5 Other Orientations → Other Orientations 4 10 In comparison, there was a considerable incubation time before the recrystallization of grains of {111}<110> and {112}<110> orientation occurred.
Recrystallization initiates from {111}<123> deformed grains and grains of orientation other than those within the α-fibre. 2.

The performance of a TiO2 photocatalyst is strongly dependent on a number of other structural factors such as crystal phase as well as grain forms and the degree of crystallinity of the TiO2 particles [5].
The solvents have affected the forms and sizes of the grains in the samples.
This process can influence the grain to growing up.
Different solvents affected on the grain size and morphology of samples.
This research is funded by Vietnam National Foundation for Science and Technology Development (NAFOSTED) under grant number 103.02-2011.12.