Search results

The structure of the serious strain area (ie, fragmentation layer) that is closest to the friction and wear surface is composed of cellular grain, subgrain and recrystallized [8].
Rigney[9] believed that the cell grain size depends on the characteristics of the material, such as stacking fault energy and the applied stress and temperature.
A large number of holes formed by vaporization of the wear surface and surface layer are observed in Rigney’s research.

ABO3-type perovskite oxides have high potential for use as catalysts in a number of catalytic reactions.
Results and discussion The synthesis of perovskite-type powers The crystal phase of the powers and grain size of the various catalysts were obtained by X Ray diffraction(Bruker D8 Advance apparatus equipped with a monochromator for Cu Kα radiation) which was operated at 40KV and 40mA, λ=0.154nm, 2θ=20°-80°.
The powders have spherical particle shape, the uniform grain size distribution, fine power size and homogenous particles.

The last two images of Fig. 2 show isolated grains, tens of nanometers in width with random surface crystallite endings.
Although grains exhibited random azimuthal orientation, film texture was generally unaffected by temperature and substrate orientation, but did become disordered as thickness increased over 400 nm on (111) Si substrates.
This work was supported in part by AFOSR grant number FA9550-07-1-0539 the Department of Electrical Engineering and 1M06002 of MSMT of the Czech Repulic.

The composition and physical properties of nickel ore vary considerably from location to location, the shippers only provide one TML certificate that has been drawn from a number of different sources, the reliability of the information and documentation which the shipper required to provide under the IMSBC Code most notably the TML certificate and FMP is questionable. 4.4 Many time the nickel ore are loaded whilst at anchorage through barges, sometimes it make ship master difficult to identify whether those barges are from the tested stockpile, during barge transportation, its moisture content may change and the interval between sample and loading exceed 7 days.
According to IMSBC Code, there are three kind of method to determine the FMP: Flow table test (drop test), suitable for concentrates or fine material of grain size 1mm (up to 7mm for some cargo types).
Proctor/Fagerberg test (compaction), suitable for fine and coarse grained ore concentrates up to 5mm.

Table 2 Feed ore -2mm screening analysis results Grain size (mm)） Yield(%) Grade (%) Al2O3 Element distribution rate (%) +2.36 9.20 27.14 11.60 -2.36+0.6 23.73 24.38 26.87 -0.6+0.3 22.68 21.62 22.77 -0.3+0.15 17.30 14.75 15.87 -0.15+0.075 15.18 18.04 12.72 －0.075 11.91 18.35 10.17 Total 100.00 21.53 100.00 It can be seen from Table 2 that as the size changing, with the increase of the fineness, the grade of Al2O3 basically tended to decrease. 2.3 Ore mineral composition Select representative ore mill made into rays, and observed under a microscope, the results are as follows: Structure: the structure is granular.
Under the polarizing microscope, it’s shape is irregular, the color is light red, grain size is between 0.4mm and 6.7mm, average size is 5.1mm.
Wave-bed gravity separation condition: XCY-73-type 1100×500 Wave-bed, length of stroke: 12mm, number of stroke: 320 times/min, obliquity: 3 degrees pulp density: 30% and feeding rate: 0.38t/h; Low magnetic separation condition: drum magnetic separator, magnetic density 1000 Oe (79.577kA/m).

When Mg2Si content further increases to 20%, the coarse dendritic crystal gradually breaks into the finer grain with dendritic- like, as shown in Fig. 1e.
Because there are the intrinsic brittleness and the serious trend of cracks at grain boundaries in Mg2Si particles from the room temperature to 450℃, the coarse Mg2Si phase with dendritic-like is more easily broken than that with fine particle-like or polygon-like under the action of external pressure, wherefore, thus hardness of the composite also decreases.
Therefore, a great number of Mg2Si nuclei will simultaneously be formed in the melt.

In the bath, the samples, indicated with numbers from 1 to 6, have been placed in different positions as schematized in Fig.1 (left hand side).
The columnar structure (Fig. 5b) of the Al grains occurred preferentially on limited sites, where dendritic growth and poor adherence to the steel substrate have been developed.
Peter, Grain growth on galvanic deposition of aluminium, Metalurgia International Vol. 5 (2011) 15-18.

Two of the most important changes involve: 1) recovery, recrystallization, and grain growth of the Cu matrix, and 2) spheroidization and coarsening of Nb filaments or ribbons [6].
Increasing the number of interfaces, increases stored energy that is the driving force for recovery, recrystallization, spheroidization and eventually coarsening [6,13].
At temperatures higher than 500 ℃, the most severely deformed samples with largest stored energy would have largest driving force for recovery, recrystallization and grain growth.

Finding the working limits of process variables Although the deformation of composite material appears to be simple, the process of determining the flow stress becomes complex due to the presence of large number of parameters which have been interacting simultaneously.
When the effects of the Orwan mechanism, the strain gradient plasticity, the grain refinement of matrix and the high dislocation density due to thermal expansion mismatch are taken into account, the calculated stress- strain curve of the composites is consistent with the experimental results in the low strain region (0.2).
[10] Z.Xue, Y.Huang and M.Li, Particle size effect in metallic materials: A study by the theory of mechanism-based strain grain gradient plasticity, Acta Materlia, 50 (2002) 149-160.

Fig. 2 XRD pattern of No. 1 specimen Fig. 3 XRD pattern of No. 2 specimen Fig. 4 XRD pattern of No. 3 specimen Fig. 5 XRD pattern of No. 4 specimen Fig. 6 XRD pattern of No. 5 specimen Fig. 7 XRD pattern of No. 6 specimen Table 1 Features of hand specimens and thin sections Number of Specimen Features of hand specimen Features of thin section No. 1 White, massive structure.
There is nearly no grain in naked eye.
The texture type of jadeite is granular-prismatic crystalloblastic texture and mylonitic texture (Fig. 9c).Jadeite crystals are very fine-grained.