Search results

The technique yields two effects during the gas injection, vigorous agitation and rapid heat extraction, so that a number of fine globular grains are created just a few degrees below the liquidus temperature.
Representative microstructures of the commercial plate at four different positions, shown in Fig. 7 (a), appear to have different grain features and sizes.

Test conditions: P = 1 MPa, friction rate 0.6 m/s, average abrasive grain size 0.06-0.08 mm (on electrocorundum grinding cloth of machine H4-B) and 0.05-0.25 mm (on НК machine).
Manual arc surfacing is characterized by a number of shortcomings, the main ones being the following: only skilled electric welders are required, since surfacing is performed at a minimum welding current in order to reduce base metal proportion in the weld deposit, furthermore it is necessary to ensure welded and base metals flash-off; severe working conditions; low productivity; large losses in fumes, spatter and electrode stubs (up to 30%).
The first provides limited heating time and increased cooling rate at high temperatures, prevents grain growth and austenite breakdown with formation of equilibrium low-strength structures.

However, they are able to degrade to low molecular weight compounds like H2O and CO2 which are non-toxic by-products in living microorganisms, since additives have different benefits which include reduction in grain size and degradability [6, 8, 9, 11].
Degradation rate was calculated by finding the instantaneous degradation ratios as follows: (2) (3) Where Di = Instantaneous Degradation Ratio wx = Former weight wy = New weight Dt = Degradation Rate (% per day) N = Number of days Results and Discussion The results of the biodegradation ratio and biodegradation rates for the 6 LDPE/Ipomoea batatas blends are shown in Fig. 2 to 7.
Analysis of the shape and size of starch grains from different botanical species.

The separation effect is not ideal because the perovskite crystalline grain is minute.
Where, firstly, the BF slag containing titanium was dealt with carbon nitriding process and the process parameters were optimized to promote the growth of carbonitride grain for separation of products.
Main phase and their percentin in BF slag containing titanium Phase composition perovskite titanaugite+ba yi mineral glassiness Carbon nitriding titanium solid iron wt, % 18-21 30-35 39-44 1 5-7 Table 3 Energy spectrum analysis with scanning electron of the slag,% Number O Mg Al Si S K Ca Ti Mn Σ 1- perovskite 32.59 - 1.06 1.18 - - 30.15 35.03 - 100 2- perovskite 32.11 - 0.43 - - - 31.08 36.38 - 100 3-posterior vitreous 42.98 5.88 10.15 17.62 0.76 1.05 18 2.77 0.79 100 4-posterior vitreous 41.43 4.36 10.02 19.15 1.36 1.73 20.28 1.67 - 100 5-bayi mineral 41.03 4.21 7.68 13.26 0.52 - 22.08 11.22 - 100 6-titanium pyroxene 40.73 5.49 10.79 17.66 - - 18.88 6.45 - 100 Thermodynamic Analysis of Carbon Nitriding Reaction The slag used in the experiment mainly contains TiO2, CaO, MgO, SiO2, Al2O3 and other oxides.

It can be observed from Fig. 2 that the grain size of the alloy milled for 15 h is significantly smaller than that of the alloy milled for 2 h.
Fig. 4 Activation performance curves for different samples Table 2 Main electrochemical properties of the samples Samples Naa Cmaxb [mAh/g] C60c [ mAh/g] S60d [%] Emide [V] As-cast 5 299.5 273.2 91.2 0.841 1 h 6 295.4 255.3 86.4 0.869 2 h 3 313.5 247.8 79.0 0.873 3 h 3 295.3 250.3 84.8 0.867 5 h 2 286.3 235.0 82.1 0.866 15 h 2 310.7 227.0 73.1 0.857 a The cycle numbers needed to activate the alloy electrode.
The grain size of the alloy milled for 15 h is significantly smaller than that of the alloy milled for 2 h.

A large number of studies on the preparation of V2O3 powder have been published in recent years since the Japanese published the preparation technology of V2O3 for the first time in 1966.
During the heat treatment of precursor powder, the autogenic gas CO, CO2 overflowed from the powder structure could destroy the original structure and refine the grains by reducing the agglomeration between ions and inhibiting the growth of grain.

One possible explanation could be that thiourea molecules coaxed producing more crystal nucleus and hindered the crystal grains growth of ZnO.
The generated electron-hole pairs had higher oxidation-reduction ability, although the numbers were lesser than that of pure ZnO.
Thiourea molecules coaxed producing more crystal nucleus and hindered the crystal grains growth of ZnO.

This failure was largely caused by the nucleation, propagation of a large number of micro-cracks inside the work piece under the action of grinding force.
crack crack a) common grinding b) f=20kHz, A=16.41μm crack b) f=20kHz, A=16.41μm c) 45kHz, A=13.57μm Fig. 2 Effect of ultrasonic frequency on surface microtopography of ZrO2 ceramics under the two-dimension ultrasonic vibration grinding (Vw＝0.25m/s, f＝2mm/r, ap=5μm, grain Size: 270#) From Fig. 2 (a), it can be seen that the more surface defects under common grinding conditions and Material fracture phenomenon is serious than ultrasonic vibration conditions, in addition, many "horns" crack produced along the direction of grinding scratches because of the effect of friction force between grinding grit and grinding, as shown amplification part in Fig. 2(a), and most of this kind of crack extend to the direction of grinding, while this kind of crack did not appear under ultrasonic grinding.
crack crack crack a) 35kHz, A=14.94μm b) 35kHz, A=4.23μm Fig. 3 Effect of amplitude on surface micro topography of ZrO2 ceramics under the two-dimension ultrasonic vibration grinding(Vw＝0.25m/s, f＝2mm/r, ap=5μm, grain Size:270#) Fig. 3 is surface microstructure of ZrO2, which frequency is 35 kHz with different amplitude under two- dimensional ultrasonic grinding.

Experimental Procedures With compounding ingots listed in Table 1, hypereutectic Al-17Si-4Cu and Al-17Si, hypoeutectic Al-7Si-4Cu and Al-7Si alloys were prepared without adding grain refining agents to primary and/or eutectic silicon.
The number of primary silicon particles extremely increases in rheocast samples with sono-solidified slurry, because the primary silicon is only 5area% in that with normally solidified slurry.
Okumiya, Grain refinement of primary silicon in hypereutectic Al-Si alloy by ultrasonic Radiation, J.

., fine or ultra-fine equiaxed grain structure is required for superplastic forming (SPF).
It can reduce or eliminate the number of sub-assembly components that would have to be individually produced otherwise into a single manufactured component, which reduces the need for multiple tooling requirements and the assembly time and cost.
However, there are some disadvantages to SPF, namely, high material cost due to the fine-grained microstructure, high process temperature and cycle time (with associated costs), expensive tooling material due to high strength and creep resistance requirements.