Search results

In addition, the TiN coating exhibited a non-stoichiometric and a transition from columnar to grain structure was observed at high poisoning levels of the target.
However, reactive sputtering process is a very complex process due to different sputtering yields of the material, the difficult to predict the number of bombardment on target surface and the obstruction of reactive gas itself to the movement of material atom.
As a result, when the number of gas atom in vacuum chamber is increased by raising gas flow and/or total pressure, there are two trends can occur: increasing the number of high ion fluxes (Ar+, N2+, N+ and N0) and/or increasing neutral gases (Ar, N2) which contribute to sputtering process efficient [8].
At high poisoning levels of the Ti target, the microstructure of the TiN coating likely turned from collumnar to grain structure.

Interpass temperature was controlled in a reasonable range that could avoid generating coarse grain structure due to high interpass temperature and making the mechanical properties become bad [6,7] .
As weld number increases, especially from ninth weld, the deviation7 is more apparent.
But the numerical simulation value and the actual measured value difference is smaller in the medium plate or weld number less model according to the results of the rest feedbacks.
Welding temperature field simulation results show that the deviation between simulated value and actual value became greater with the increase of number of weld or thickness.
Influence of welding thermal cycle on toughness and microstructure in grain-coarsening region ofX80pipeline steel .Transactions of The China Welding Institution. 8 (2005)69-72 [7] XUE Song-bai, WU Yu-xiu, CUI Guo-ping, ZHANG Ling.

Coarse and fine-grained AlN powders in ratio 70 : 30, 2 wt.-% of Y2O3 as well as Dolapix PC 33 were added to the solvent under constant stirring.
Fig. 2 shows that the reaction of fine-grained AlN powder with water is prevented within the first 4 - 6 h after preparation, but for higher particle concentrations a minor change in pH is detected at longer leaching times which is reflected in the slope m.
The number of water molecules that are bound to the particle surfaces increase restricting the growth of large continuous crystals.
Apart from few ice replica, most pores are induced by breakouts during polishing (angular pores numbered with 1) and gas bubbles during casting (small roundly shaped pores numbered with 2) which have to be removed in further experiments by evacuation of the suspension before freeze casting.

So the inlet boundary condition is set as changeable mass inlet to adapt the grain’s burning law [3].
The chamber pressure is written herein to calculate the mass flow rate as follow: (1) where is the area of grain; is the area of the inlet of nozzle; is the density of propellant; is the pressure of chamber; n is the exponent of the burn rate; a is the coefficient of the burn rate.
The Root Mean Square Error (RMSE) is used to evaluate the accuracy of the method: (2) where, is the result calculated by CFD; is the result predicted by the response surface; N is the number of points.
Fig.2 The response surface generated using the Kriging model Table 1: Results of the optimization Begin Point Optimal Point Rounding Optimal Point Parameters α/(º) 45 43.722 44 R1/mm 5.5 3 3 R2/mm 140 100 100 Re/mm 23 26 26 θ/(º) 45 43.06 43 r/mm 1.5 1.330 8 1.3 Loss of specific impulse η/% 9.01 4.52 4.50 Fig.3 Mach number contour before the optimization Fig.4 Mach number contour after the optimization Analysis of the Key ParametersThe sensitivity of all the parameters is shown in figure 5.

A number of sample cross-sections are illustrated in Fig. 3.
Fig. 4 illustrates a number of different shapes for the inner contour of the tube that is manufactured.
The initial, primarily isometric, grain structure changes into significantly elongated grains in the deformed section of the part.
This results in a low economic batch quantity, permitting costefficient manufacture in small numbers (for prototypes e.g.).

It is annealed in vacuum heat treatment furnace at 720 ℃ for 20 min for recrystallization, the average grain grade is 7.
And Zhang [8] thought that the Cottrell atmosphere density can exceed the critical value at lower pre-strain, so the BH value depends on the number of Cottrell atmosphere.
This paper thought that when the pre-strain fails to reach the critical point M, the amount of dislocations increases with pre-strain increasing, which makes interstitial atoms relative increase to form Cottrell atmosphere, which makes the number of Cottrell atmosphere increase, and strengthen effect is obvious, namely AB section.
Which improved that the effect of dislocation density on the BH is crucial, when the density dislocation is larger, the number of Cottrell atmosphere is more, so that the BH is higher.
With the dislocation density increasing, when the amount of dislocations exceeds the limited value within the grain, there would be some mobility dislocations, and the amount of which would increase with dislocation density, which is consistent with mine.

Fig. 1 Die-forging of connecting rod Table 1 Simulation Parameters Simulation parameter Value Environment temperature[℃] 20 Forging temperature[℃] 430 Die’s preheating temperature[℃] 200 Fraction factor 0.3 Heat transfer coefficient[N/sec/mm/℃] 11 Mesh number of billet 150000 Mesh number of upper die 250000 Mesh number of lower die 250000 Poisson ratio 0.3 Punch velocity[mm/s] 50 Stroke[mm] 46 Fig.3 Temperature field in die-forging of the connecting rod: (a)-(d) Fig.2 Distribution of connecting nodes of billet with dies Fig.4 Effective stress field in die-forging of the connecting rod: (a)-(d) Fig.5 Maximum principal stress field in die-forging of the connecting rod: (a)-(d) The billet temperature is kept below 500℃, and the distribution of the maximum temperature occurs on flash as is shown in Fig.3, so billet temperature distribution is reasonable.
Low temperature leads to hard flow ability, poor die filling and large deformation resistance, then increases die wear and reduces die life; High temperature leads to the oxidation of the surface and the forming large grain of the rod, which reduces the mechanical performance of the billet.
Fig.8 Change of effective stress and upsetting force with initial forging temperature Fig.9 Change of effective stress and temperature of upper die with initial forging temperature However, the high initial forging temperature will produce coarse grains, reduce the strength and resistance to aluminum stress corrosion, especially with the initial temperature 455℃，local temperature of the billet is close to the over burning temperature of 7075.

The temperature dependent resistance and the noise characteristics of an individual multi-wall carbon nanotube (CNT) decorated with a finite number of magnetic nanocubes are investigated.
An example of a fabricated device – a MWCNT decorated with a finite number of iron nanocubes – is presented in Fig. 1.
For the calculations we used values available in the literature: cFe = 0.449 J/(g K), cCNT = 0.71 J/(g K) [11], rFe = 7.86 g cm–3, rCNT = 1.3 g cm–3, the thermal conductivity of CNT k = 3000 W/(K m) [12], and the average power density absorbed by magnetic grains p = 62 kW/cm3 [13].
Farle, The route to single magnetic particle detection: a carbon nanotube decorated with a finite number of nanocubes, Nanotechnology 20 (2009) 335301-5

Davies1, 2, c 1 School of Physics and Materials Engineering, Monash University, VIC 3800, Australia 2 Victorian Centre for Advanced Materials Manufacturing, PO Box 62, Belmont, VIC 3216, Australia a Elena.Pereloma@spme.monash.edu.au, bAzdiar.Gazder@spme.monash.edu.au, cChris.Davies@spme.monash.edu.au Keywords: ECAE, texture, torsion, shear Abstract Texture development and grain refinement of interstitial-free (IF) steel as a function of ideal simple shear or torsion was undertaken for up to 8 pressings, Route BC.
Since the character of ECAE deformation is dominated by the latest strain, component evolution can be analysed by the number of passes and cumulative strain.
Moreover, a deviation of these components away from their ideal shear orientation(s) is observed with greater number of passes.
The measured average grain size of the annealed specimens before ECAE ranged between 100 and 150 µm.
The same deviation by approximately 10 o-20o from the ideal simple shear texture has been previously reported by several authors for 90 o ECAE (εeff ≈ 1.16 / pass) who concluded that greater numbers of pressing would result in higher deviations away from ideal orientation positions [8-10].

Despite a large number of studies concerning cavitation behaviors in superplastic materials [3-5], only a few data – obtained from exactly as-deformed specimens, i.e., without the surface preparation – have been reported so far.
Experimental The material used in this study is a fine-grained 3Y-TZP with an average grain size of 390 nm.
The Q value at the flexed position indicates the mean size (radius) of cavities accounting for the largest in number among all cavities existing in the specimens, since the scattering intensity is proportional to the product of cavity volume fraction multiplied by cavity size.
The major part of volume fraction of all cavities existing in each specimen is therefore occupied by the cavities with the radii of about 200 nm, which correspond to the mean grain radius of the specimen.
It was also found that the grain size and unevenness of the fracture surface in the specimen deformed under PSC are larger than those in the specimen deformed under HSC.