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Table1 Chemical compositions of duplex stainless steel (mass/%) Chemical compositions C Si Mn S P Cr Ni Mo duplex stainless steel 0.016 0.35 0.32 0.0034 0.019 11.92 0.079 0.02 Choice of metallurgical show methods of stainless steel Because stainless steel has good corrosion resistance, showing the matrix grain boundaries is difficult, in particular, showing the complete boundary.
Table2 Preparation of several common chemical etching agent of stainless steel Serial number Chemical compositions of reagent No.1 reagent picric acid 1g Hydrochloric acid 5mL Alcohol 100mL No.2 reagent copper salt 4g Hydrochloric acid 20mL Distilled water 20mL No.3 reagent Nitric acid 10mL Hydrochloric acid 30mL No.4 reagent Nitric acid 10mL Hydrochloric acid 20mL Alcohol 10mL According to the experimental materials, heat treatment process and metal science principles, the microstructure should be a small amount of undissolved ferrite and martensite obtained by quenching after heat treatment.
By observing metallographic microstructure, it is found that corrosion effect of No.2 reagent is better, grain boundaries is obvious.
When time is short, the grain boundary is not obvious.
It is easy to control corrosion time and grain boundaries is obvious.

Fig.1 Deformed flow line traced by Stevenson and Oxley [4] 2 Results Discussion (a) Strain distribution (b) Strain rate distribution Fig. 2 Deformed flow line in simulation 2.1 Comparison in Deformed Grid Actually, workpiece material removed is composed of a large number of grains.
Due to the rapidly large deformation and high temperature in primary shear zone, the structure of grain will changed greatly when the grain flows out the primary shear zone.
The grain will be elongated and the direction of elongation is considerably different with the shear direction defined by shear plane model.

Experimental The material used for current study as the samples for MDF is commercial as-cast ZK60 with chemical composition of Mg-5.54% Zn-0.65% Zr (in mass %) and initial grain size of about 200 μm.
It can be found that basal planes in large number of grains are oriented normal to the forging direction at both upper and lower parts.
Twinning deformation is greatly related to the grains size and its orientation [10].
Since the start ZK60 has relatively large grains about 200 μm twinning deformation is preferred to happen.

A large number of alloying elements improve the cost of weathering steels, which is a serious hindrance to promote and use of weathering steels.
In the rolling process, the deformation induced Nb (C, N) or (Ti, Nb) (C, N) precipitation in austenite grain boundaries, dislocations or deformation bands (Fig.3~4 ), which prevent grain coarsening and recrystallization nucleation, inhibit recrystallization, so that the ferrite grain refinement, played the role of fine grain strengthening, improving strength and toughness of steel.

The results in Table 2 confirm that the aluminum matrix undergoes grain refinement, but also particles are ground to a lower dimension.
Area Particle area [µm2] Particle major axis [µm] Particle shape factor (1=circle;0=line) Av. grain size [µm] Base mat. 102.1 10.8 0.65 24.9 Nugget 69.3 7.9 0.68 12.8 Nugget TMAZ 1mm HAZ Tests.
The difference in Rvs between base PMMC and FSW joint at low crack growth velocities (see Table 3) is attributed to the competition between two effects i) grain refinement due to dynamic recristallization and ii) particle fragmentation due to stirring.
With finer grains, Stage II (duplex slip) type of crack propagation in the metal-matrix is more likely to occur even at low velocities leading to a lower Rv.
Only in the case of a high particle content, as in the case of AA6061/Al2O3/20p, this is compensated by the higher number of crack deflections caused by fragmented particles, that increases Rv.

The oxides grain size at 700oC seems bigger and the amount of growth is higher than 550oC.
Almost a threefold increase in oxide grain size is observed for samples oxidized at 850oC as compared to that of 700oC.
Higher heating temperature seems to impart more energy to the smaller oxide grain for agglomeration.
Increasing in oxidation temperature seems to increase the nucleation growth of oxide scales and finally agglomerates to form bigger grain oxide scales.
Acknowledgements Authors would like to express highest gratitude to Ministry of Higher Education (MOHE), Malaysia and Faculty of Mechanical Engineering, UTM for funding this research project via vote number Q.J130000.7124.02H60 and providing their facilities respectively.

The platelet grains introduced as the second phase can function as reinforcements similar to whiskers or fibers in reinforced ceramics which can improve the fracture toughness appearently, so the synthesis of platelet alumina powders has important significance to promote the development of high performance ceramics.
A number of wet chemical methods have been developed over the years for the production of alunimia powders [1-3] which allow a very fine and reactive powder to be prepared, and the powder characteristics can be easily modified by changing the conditions during powder synthesis.
SEM images of powders calcinated at different temperatures are showed in Fig.6, The shape of the powders was unchanged with increasing calcinations temperatures while no additives was introduced, as we can see from Fig6 (a-c). the appearence of the grain with additive calcinated at 1000°C is still similar to that without additive, But appearently, the shape of the grains changed markedly after the calcination temperature highter than 1100°C.
Also no agglomerate or big grains presence.

Introduction The sizes of electronic devices including cell phones, computers, MEMS, detectors are getting smaller due to rapid development of semiconductor process in order to maintain the Moore's law, a rule of the number of transistors that can be placed inexpensively on an integrated circuit doubles approximately every two years.
Nieman et. al [1] present that the microhardness of nanocystalline Cu produced by inert gas condensation with fine grain size 3-50 nm is higher than that of coarse-grained Cu.
The yield strength of pure nanocrystalline Cu has six times higher than that of coarse-grained Cu [2].
Although the flow stress along with the grain boundary increases as increasing strain rate, the actual effect of the strain rate is highly dependent on the nature of the tested material [4].

On the “Polema” powder, a greater number of satellites were detected in comparison with the “SphereM” powder.
Table 3 presents the results of the grain size analysis of the initial powders, as well as the averaged results of the mechanical tests of the samples from the "Polema" 09CrNi2MoCu powder.
The pictures show large amount of facets with a fine-grained structure and traces of plastic deformation on kinks grown from primary powder, which indicated viscous nature of the fracture.
During the formation of the microstructure - the powder "Polema" forms a smaller and elongated ferrite grain, while forming the microstructure - the powder "SphereM" a larger ferrite grain is formed relative to the first case [10-11].

So far, it is known that the strengthening of metals can be achieved by introducing a large number of lattice defects, such as vacancies, interstitial atoms, dislocations, grain boundaries, interphase boundaries, stacking faults, twins, dispersed particles, and so on [1, 2].
As is known, heavily cold-deformation introduces not only dislocations but also other lattice defects, for examples, vacancies, twins, and grain boundaries due to grain refinement, into metals [11].
TEM investigations indicate that there are no signs of grain refinement and twins presenting in microstructures of the cold-rolled Pd samples, only dense dislocation networks can be observed [9].