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O2 Flow(sccm) 300 400 500 600 700 Roughness Average(nm) 33.4 28 6.72 3.77 4.23 RMS(nm) 41.1 36 8.55 4.77 5.4 Diameter Average(nm) 271 133 89.1 77.7 76.5 The AFM measurements shows that the average grain size of the films got smaller with the increasing of O2 flow, and the roughness average, RMS are nearly with the same trend.
We can see that the grain size get smaller.
The grain size, the roughness average, the RMS of the films are affected by the O2 partial pressure.
Acknowledgements This work was funded by NCET (No.05-0326), NSFC (No. 60576054, 60876013), Project of Changchun science and technology plans with contract number of 2006303, Project of Ministry of Construction P.

As a result, each grain changes its shape as the temperature changes, which puts severe stresses on the grain boundaries.
Schematic of cracking in a thick deposit of consolidant at the point of contact between grains.
Normalized mass of Ohio Massilian sandstone versus number of cycles in sodium sulfate test: soaking in 16 wt% Na2SO4 and drying at 60˚C.
The large angular particles are grains of the stone.
Brenner, Low Reynolds number hydrodynamics (Martinus Nijhoff, Dordrecht, 1986) [26] C.

Fig.2 is the uncorrosive microstructure that the test bar fabricated by liquid forging is unhandled with solution ageing technology,α（Al）+Si+ Al2Cu+ Mg2Si.After adopt the liquid forging craft, improving the condensation rate can make the α（Al） crystalline grain turn from the thick dendritc grain into the fine equiaxed grain during the forming process and the primary crystal phase and eutectic microstructure distribute refinedly and uniformly.With the acceleration of condensation cooling rate,microstructure is also gradually become smaller and even the acicular,platelike eutectic microstructure isn’t seen while dendritic aluminum solid solution is more obvious.
The major strengthening phaseθ（Al2Cu）and Mg2Si are eutectic alloy.So on 525℃,when the composition are 27% Cu and 5% Si,there is a ternary eutectic reaction L→α（Al）+ Si+ Al2Cu,but it doesn’t exit ternary compound.Then the biggest solubility of Cu and Si in the α (Al) separately is 4.6% and 1.1% [5].Therefore,on the equilibrium crystallization α (Al) crystallization is first,then there is binary eutectic reaction of L→α（Al）+ Si until the end of the crystallization[4].So the solid solution temperature is not too high.Adopting the hierarchical way of heating is to prevent the low melting point eutectic occurring the grain boundary re-melting (overburning) and re-melting ball.
The AlFeMnSi andβ（Al9Fe2Si2 ）phase are brittle.With the increasing of iron content,they are significantly raised and on the acicular shape come through theα（Al） grain.It has disadvantageous influence on the mechanical properties of alloy.We can reduce even eliminate the influence of acicular rion phase and make microstructure properties achieve the international standard requirement(about 9%).
Investment casting process produces a large number of loose and uneven bulky microstructure that leads to its mechanical properties are poor.

Using this technique a large number of natural rocks and single crystals were deformed at elevated pressures and temperatures, The experimental results were compared with structure and texture of natural rocks and with seismic anisotropy data.
Grain-size-sensitive creep processes and the influence of water and other volatiles require well-characterized starting conditions, i.e. parallel experiments with synthetic polymineral assemblages.
The influence of water and grain size could be investigated now [6].
The extremely small sample size excludes polymineral assemblages and grain boundary effects.
The underlying principle is that the distance between atoms represents the elastic strain of individual grains by the stress.

However, magnesium has a hexagonal closed-packed (HCP) crystal structure with a limited number of operative slip systems at room temperature, and its formability is restricted to mild deformation [1, 2].
It is also known that Zr plays an important role of grain refinement during solidification.
The grain structure was revealed by subsequent etching with a solution of picric acid (5 g), acetic acid (5 ml), water (10 ml), and ethanol (100 ml).
RESULTS AND DISCUSSION Solution Treatment The condition for solution treatment was determined, which show relatively lower hardness value and smaller grain size with variation of temperature and holding times for solution treatment.
While, the grain sizes of specimens at above solution treated condition are 10, 20, 30, 60 µm, respectively.

A number of hypotheses have been formulated concerning this so called 'reactive element effect'[10].
%) to produce large grained ferrite, the alloys were cut into coupons which were ground to a 1200 grit finish and cleaned ultrasonically in ethanol immediately prior use.
This described the growth of the chromia was governed by chromium diffusion through oxide grain boundaries.
The presence of a reactive element at grain boundaries may block them, as diffusion paths.
Thus, a segregation of reactive metal oxides to the grain boundaries may explain the decreased chromium transport and decreased growth rate of chromia.

And after peak aging stage at 135℃, the number of coarse phase become more, which will worsen the mechanical properties of the alloy.
Moreover, the phases distributing along the grain boundary will become discontinuous.
The disgregated phases along the grain boundary are helpful to improve the stress corrosion crack performance of 7B04 alloy.
The phases distribute along the grain boundary is disgregated and the precipitation inside the grain is very fine and homogeneous.
Along the grain boundary, there is a bout 10nm-width free precipitation zone (FPZ).

Advantages of the process are [4]: · Reduction of number of steps for producing components
This is remarkable as addition of phosphorous may lead to brittleness and hot shortness in conventional alloys due to segregation of phosphorous to grain boundaries [7].
All the samples exhibited single phase recrystallized grain structure with grain size of 50 to 100 microns with some porosity within the grains as well as at the grain boundaries.

This classification defines whether the nucleation and/or growth of strain free recrystallized grains occur during or after deformation [1-3].
This leads to the strain accumulation in the austenite resulting in a fine ferrite grain size after transformation.
A number of studies have examined the effect of thermomechanical conditions, such as temperature, strain and strain rate on the hot deformation behaviour of steels.
This can be explained by the solute drag effect of Nb, which retards the mobility of grain boundaries (i.e. recrystallization) [3].
The effect of Nb(C,N) precipitates on grain boundary mobility through pinning is much stronger than Nb will have in solution through solute drag.

Experimental conditions for the preparation of the samples and thickness after annealing Sample A Sample B Sample C Withdrawal speed [cm.min -1] 1.5 1.5 10 Layers number 6 10 10 Preheating temperature [ºC] 400 400 400 Final thickness [nm] 160 270 350 Table 2.
These results were confirmed by SEM analysis, which revealed the negative effect of reducing atmosphere during cooling in terms of grain size.
The effect of nitrogen atmosphere during PT2 is smaller in terms of grain size (Fig. 1) but very important in what concern electron carrier concentration and mobility.
This is due to the high grain size and to the decrease of free Zn atoms concentration determined by the oxidation of these atoms.
In addition to the effect of orientation, the increase in grain-packing density could also contribute to the decrease in resistivity.