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Early in the processing, pieces of materials removal is mainly in the form of lapping, abrasives makes the surface plow and scrap to remove as the way of sliding and rolling; At the same time, with appropriate pressure, abrasive fractured, blunt, the number becomes more positive, the size smaller, blunt corner angle, shear action smaller, at this point in the process turntable remove the surface friction as methods of polishing[3], so that quality of machined surface is fully improved.
On this basis, the additive in the polishing liquid is processed in the surface layer attached to the membrane, With the smooth surface of the work piece further increase, further reduce the particle size and uniformity of abrasive, integration with the attached film grain to form a smooth, good flexibility and uniformity film on the surface of the flexible polishing to remove, with the new surface and new attachment formation and removal of alternate film, the machined surface quality is getting better and better, so as to achieve high surface quality[4].
Table 1 The chemical constitution and mechanical property of W-Mo alloy Material Chemical constitution Mechanical property W-Mo alloy W Mo Ni Fe σb σ0.2 HB 80 15 2.5 2.5 680N[mm2] 650N[mm2] 210 Table 2 The experimental installation ELID grinding condition Machine MSG-612CNC-FA grinding machine Wheel Cast iron bonded diamonds wheel (W36, W10, W5, W1.5) Power source Special dc pulse supply Grinding fluid Special grinding fluid［5］ Polishing condition Producing machine Conversion speed regulation optics biaxial polishing machine Polishing pad Thin blanketing or cotton fabric Polishing fluid Ⅰ White alundum(grain size W1)+40 times coal oil + little animal oil and seed oil Ⅱ Diamond(grain size W0.5)+ 45 times coal oil + lubricant grease and seed oil Measure machine HALIANG2205 surface roughness admeasuring apparatus
W5 wheel ELID grinding rendering W5 wheel measurements Ra=0.022μm Fig.2 ELID grinding effect and results W1.5 wheel measurements Ra=0.032μm Ra=0.018μm Fig.3 ELID grinding effect and results Fig.4 The result with polishing fluid Ⅰ Because W-Mo alloy has good toughness, hard chip breaking, precision grinding wheel easily blocked, big grinding force, high grinding temperature, when adopt lower grain size(W1.5) wheel to grinding, surface burns easily, surface roughness of Ra=0.032μm was obtained, so we must adopt ultra-precision polishing to further improve the surface accuracy, in scores of experiments, obtain the lapping parameter such as Table 3, surface roughness of Ra=0.011μm was obtained with polishing fluid Ⅱ.Fig.3 shows machining rendering and the surface measurement results.
Conclusion According to the experimental studies for ultra precision mirror processing of W-Mo alloy, we can reach some conclusions: 1) Adopt ELID grinding ultra-precision processing method, a machined surface roughness of Ra=0.022μm can be obtained. 2) In the process of ultra-precision mechanical lapping and polishing on W-Mo alloy, choose to fluid Ⅱ, pressure is 0.1～0.3 N/cm2, rotational speed is 60～100 r/min, eccentricity of the sample and polishing dish is 45mm, abrasive have the best rolling effect for machined surface, the surface of Ra = 0.011 nm can be obtained. 3) In lapping and polishing process, abrasive size and modulus of elasticity of felt determine the bigness of surface pressure and remove force, positive pressure of abrasive acting on the machined surface increases with the increase of grain size and modulus of elasticity of polishing dish.

The transformation of the base material, during the welding process, consists in chemical composition, volume, and microstructural, e.g. grain size changes.
Some of the issues that may occur when welding carbon and stainless steels are the following [1, 3, 5]: ü the formation of layers with changing composition in seam: In the weld metal grains with different networks may emerge; ü the formation of diffusion zones in the welded seam: This phenomenon is caused by the diffusion of Carbon from the carbon steel towards the austenitic one, resulting in a decarburized area with a lower hardness in the base material and a hardened area in the seam where Carbon diffused; ü susceptibility to cracking: The cracks may appear at temperatures above 1200ºC.
They are stymied by low melting point eutectic segregations pollution components at the grain boundary; ü sensitization to the intercrystalline corrosion: During the welding operation of austenitic stainless steels, sensitive areas appear at the intercrystalline corrosion on both sides of the weld seam as a result of having taken the temperature range 400-800 ºC, when the adjacent areas depleted in Chromium due to precipitation of chromium carbides at the grain boundary, at the same time as residual stress.
a) x500 b) x200 Fig. 4 HAZ microstructure a) Carbon steel S235JR + AR side, b) stainless steel X2CrNiMo17-12-2 side a) x200 b) x200 Fig. 5 Welded seam microstructure The microstructure shows the presence of the dendritic grains in the weld metal (Fig. 5).
To analyze how the base materials contribute when forming the welding joint, there were processed a number of features presented in table 5 and in the figure 7.

The qualitative and quantitative evolution of the crystallographic texture during recrystallization annealing is affected by a number of parameters such as strain mode and strain amplitude as well as thermal parameters pertaining to annealing time and temperature.
The coarse grained as-cast equi-axed microstructure changes its morphology during rolling while the presence of non-deformable particles shapes the deformed grains.
Material A reveals inhomogeneous microstructures consisting of bands of various grain sizes, whereas the microstructure of material B is more homogeneous (c.f.
By comparison of the recrystallization textures of Fig. 4 c and d with the calculated TF maps, it can be seen that the recrystallized grains cover the domains of low stored energies on condition that these different strain modes are considered.
Increasing the amount of particles raises the relevance of the PSN mechanism and thus, the measured recrystallization textures comprise low stored energy grains resulting from this mechanism.

The distribution characteristic of cumulative grain - size curve.
The cumulative grain - size distribution curve displays two stage generally, which is constituted by jumping-point and suspended point.
The composition of underwater distributary channel is mainly fine-grained sandstone, massive fine sandstone powder, wavy bedding fine sandstone powder and pebbly sandstone at the bottom.
The probability cumulative grain size curve is characterized by two-stage plus transition.
The latitude increases from bottom to top, forming product-type combination, represents the character of a number of anti-grain sequence of sedimention, which is consistent with the former sendimention of sand body ( Fig.2).

AlTi5B1 rod type grain refiner was also added to the molten metal.
Fig. 1 (a) 3D models of automotive wheel hub, (b) wheels’ section number along the XZ plane.
The first solidified position of inside rim and rim has a smaller grain size (Fig. 5 A, B, C), but there still exists little dendrites, which is due to higher cooling rate.
But the grain size has become larger than rim and inside rim because of spoke and hub is massive and thermal dissipation is slow.
Therefore, to prevent grain growth need to consider the factor of die design, cooling and filling process.

A more integral character and larger grains can be observed in the Fig.2.
The results show that doping of SiO2 restrained growth of the grains and promoted forming of nano-particles.
The mechanism of inhibiting the grain growth of TiO2 is strongly dependent on the distribution manner of oxide additives in the microstructure of the materials.
The results show that the surface morphology is quite similar with two samples, for the doping of SiO2 restraining growth of the grains.
Fig. 5 Glossiness of enamels as a function of dipping cycle numbers of the TiO2/SiO2 thin film The results show that the gloss property of the enamel without film was 90.

TEM topography indicated that nano TiO2 was dispersed uniformly in the matrix material and the grain sizes were in the range of 20-50nm in diameter.
Previous research indicated that the average grain size of nano particles depend on the temperature and time of ultrasonic vibrations treatment [3~8].
It was due to that nano TiO2 could be dispersed effectively at certain concentration range and grain of nano TiO2 contacted with ultraviolet increased which contributed to increased degradation efficiency [11].
TEM image of specimens by the optimal scheme showed that nano TiO2 was dispersed uniformly in the matrix and the grain sizes were in the range of 20-50 nm in diameter and size of matrix material particle were smaller under high speed shearing and ultrasonic treatment.
Nano TiO2 was dispersed uniformly in the matrix material and the grain sizes were in the range of 20-50 nm in diameter by this scheme.

Both alloys show a nearly fully lamellar microstructure ( and 2 phases) with variable grains size (see Table 1) and on the grain boundaries, some smaller areas without the lamellar substructure of single phase are present (Table 1).
In 7Nb alloy other minority phases were identified either in regions between lamellas  and 2 phases or in regions close to grain boundaries.
Room temperature TC was measured up to the Ti Al Nb Cr Ni Si B Grain-colonies size Lamellar thickness  grain fraction 2Nb alloy 47.61 47.56 2.04 1.96 - - 0.82 0.08 - 1 mm 1.95 m 6 % 7Nb alloy 47.80 44.20 7.80 0.70 0.2 0.1 - 0.1 - 1.2 mm 0.87 m 3 % (a) (b) Fig. 1.
The numbers of cycles to failure for the two materials at RT are very close.

It is found that the substitution of M (M=Cu, Mn) for Ni brings on a evident refinement of the grains in the alloys.
It is viewable that the as-spun (20 m/s) M2 and M4 (M=Cu) alloys exhibit an Fig.1 XRD patterns of the as-spun (20 m/s) Mg20Ni10-xMx (M=Cu, Mn; x=0-4) alloys: (a) M=Cu; (b) M=Mn Table 1 Lattice parameters, cell volume, FWHM values of the major diffraction peaks of the alloys Alloy M content FWHM Grain sizes Lattice parameters and cell Volumes 2θ = 45.14° D203 /nm a/nm c/nm V/nm3 M=Cu x=0 0.179 48 0.5211 1.3265 0.3119 x=1 0.237 36 0.5216 1.3277 0.3128 x=2 0.242 35 0.5217 1.3311 0.3137 x=3 0.259 33 0.5219 1.3319 0.3142 x=4 0.273 31 0.5221 1.3323 0.3145 M=Mn x=0 0.179 48 0.5211 1.3265 0.3119 x=1 0.320 27 0.5216 1.3288 0.3131 x=2 0.544 16 0.5217 1.3312 0.3138 x=3 0.603 14 0.5221 1.3319 0.3144 x=4 — — — — — Fig. 2 HRTEM micrographs of the as-spun (20 m/s) Mg20Ni10-xMx (M=Cu, Mn; x=0-4) alloys (a) and (b) M2 and M4 (M=Cu), (c) and (d) M2 and M4 (M=Mn), entire crystalline structure.
And some crystal defects such as subgrains and grain boundaries can be seen clearly from the amplified morphologies of Fig.2 (a) and (b).
The superior hydrogen absorption kinetics is undoubtedly associated with the refinement of the grains generated by the melt spinning and M (M=Cu, Mn) substitution.
The large number of interfaces and grain boundaries available in the nanocrystalline materials provide easy pathways for hydrogen diffusion and accelerate the hydrogen absorbing/desorbing process [7].

The results show that the smaller the grain size, the better the field emission performance.
Wang et al. prepared nano-diamond films with grain size of 15-20nm by microwave CVD method.
The introduction of conductive grain boundaries into the material structure was helpful to improve the conductivity of the material.
In an ideal state, a large number of "micro tips" formed by sharp edges and angles of nano-diamond particles are evenly distributed on the surface of diamond layer.
On the nature of grain boundaries in nanocrystalline diamond.MRS Bulletin [J] 2008, 123(9): 36-41