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Online since: July 2012
Authors: V.F. Neto, J. Grácio, J.A. Santos, D. Ruch
Table 1 – Overview of investigated samples Sample Substrate Pre-treatment Interlayer A Si - - B WC-Co - - C WC-Ni - - D WC-Co Chemically etched - E WC-Ni Chemically etched - F WC-Co - CrN G WC-Ni - CrN H WC-Co - AlTiN I WC-Ni - AlTiN J Ti6Al4V - - Table 2 – Substrate properties (data gently supplied by Durit, Lda. for WC-Co and WC-Ni; other materials were purchased and date were obtain from supplied datasheets) Substrate Chemical Composition WC Grain size [µm] Density [g/cm3] Vickers Hardness Thermal expansion [10-6/K-1] Poisson's ratio Young's modulus (GPa) WC-Co 94%WC, 6%Co 2.5 14.95 1600 5 0.26 630 WC-Ni 93%WC, 7%Ni 1.2 14.85 1530 5.3 - - Si Si - 2.3 - 5.1 0.21 155.8 Ti6Al4V 90% Ti, 6%Al, 4%V - 4.5 354 9.2 0.32 115 The CrN and AlTiN intermediate films were deposited by Prirev, Lda, onto WC-Co and WC-Ni samples, using a PVD-arc reactor.
Table 3 - Interlayer properties (data gently supplied by Prirev, Lda) Interlayer Deposition temperature (°C) Thickness (μm) Vickers Hardness Roughness (Ra µm) Friction Ratio CrN 350 3 2100±300 0.20 0.50 AlTiN 450 3 4000±500 0.15 0.40 In order to enhance the diamond nucleation, the samples have been ultrasonically abraded for 1 hour in a diamond suspension, prepared using 1carat of 0.25 μm grain size of commercial diamond powder, dissolved in 20 ml of pure methanol.
Table 4 – Overview of the deposition conditions Parameter Value Pressure [Torr] 30 Substrate Temperature [ºC] 500-550 %Ar/(H2+Ar) 82 %CH4/(H2+CH4) 4 Total gas flow [sccm] 200 Deposition Time [min] 420 All samples were characterized by a Scanning Electron Microscopy system, equipped with an Energy dispersive X-ray spectroscopy (SEM/EDS - Hitachi 4100), a Raman spectroscopy system (JOBIN YVON HR800UV) operated at room temperature and equipped with an ion laser with a wave-number of 325 cm-1.
This can be because of the high percentage of amorphous phase, due to the presence of Co in substrate surface which promotes the solubility of carbon and therefore the formation of a graphitic layer. [9, 14] On the case of the WC-Ni, the presence of Ni in the substrate surface doesn’t promote the formation of non-diamond phases during the depositions [15], however, it originates the formation of round Ni particles over the gaps between WC grain boundaries, as it can be observed in fig. 1-d).
For the chemically etched samples, (samples D and E), the nodules are smaller, about 300nm, but in greater number than in the case of the samples with interlayers (samples F, G, H and I).
Online since: April 2013
Authors: Seppo Leinonen
Assemblage number Assemblage mineralogy Number of samples 1. talc - carbonate - chlorite 17 2. talc - carbonate - serpentine - chlorite ± tremolite 11 5. serpentine - carbonate - talc - chlorite 7 4. talc - tremolite - chlorite ± carbonate 3 3. talc - serpentine - tremolite - chlorite 3 6. talc - chlorite 3 Soapstone comprises talc, carbonate, chlorite and Fe-oxides with occasional serpentine and amphibole (Fig. 5).
Eastern Finland soapstone thin sections in cross polarized light: (A) a serpentine soapstone composing fine-grained talc, carbonate and serpentine, sample No. 745-47.70; (B) a serpentine soapstone with serpentine and iddingsite after olivine porphyroblast surrounded by carbonate and fine-grained talc, sample No. 3.1.5.3.6.3; (C) a talc-carbonate soapstone with coarse talc partly replaced skeletal magnesite crystals, sample No.
P21-70.80; (D) a tremolite soapstone composing fine-grained to flaky talc and variolitic tremolite, sample No. vuke-385.
Online since: January 2002
Authors: Alexander M. Korsunsky, Jonathan R. Tuck, Aghasi R. Torosyan, Svetlana A. Barseghyan
Hardness of the coating was chosen as a key property, since it is indicative of the work-hardened state of the material in the layer, the grain size and hence the coating strength.
Two materials were used for substrate, an A1 aluminum alloy (UNS number A91100), and a low carbon steel (UNS number G10100).
As a consequence, the coating is composed of titanium grains which have undergone a much more severe plastic deformation, and become work-hardened to a greater extent.
This is likely to be reflected in the grain size and dislocation density in the two coatings.
Online since: September 2018
Authors: Yurii F. Ivanov, Anton D. Teresov, Vladimir Shugurov, Olga V. Ivanova, Gennadii G. Volokitin, Аnatoliy A. Klopotov, Elizaveta A. Petrikova
Pilot plants equipped with electron guns have been developed at the ISE of the SB RAS, allowing to perform scientific research at various values of the energy density in the electron beam, duration, repetition frequency, and the number of irradiation pulses [6, 7].
Irradiation modes: electron energy is 17 keV; energy density of the electron beam in the pulse is (20, 30, 40) J/cm2; pulse duration is 200 μs; repetition rate is 0.3 s-1; number of pulses is 3.
Grain boundaries have a wavy relief, which indicates the incompleteness of the modified layer recrystallization process.
The internal structure of grains is represented by crystallization cells, the characteristic image of which is shown in Figures 2b and 2c.
The arrows indicate the wavy grain boundary on (a) and particles of the second phase on (c).
Online since: March 2019
Authors: Dominique Mangelinck
Growth of Silicides: General Behaviour The growth of silicide has been the subject of a large number of studies that were summarized in several reviews [6,8].
Different grain sizes (ranging from 10 to 0.1 µm) are used to calculate Deff .
Indeed Pt was found to segregate at the grain boundary of δ-Ni2Si [52] and could thus decrease the GB diffusion of Ni.
Grain growth in the barrier might also induce a change in the effective diffusion coefficient taking into account both inter and intra grain diffusion in the barrier.
Even if these parameters may depend on the barrier microstructure (for example grain size, grain structure, texture…), our first experiment shows that, for a given deposition process (sputtering in our case), these parameters could be materials constants.
Online since: December 2006
Authors: Chang Kyu Rhee, Wheung Whoe Kim, G.M. Kim, Sung Mo Hong, Min Ku Lee, G.H. Kim
It is notable to see that the de,max increased stepwise-like with the number of impacts n as illustrated by the arrows in Fig. 2 (a).
It was observed that the variation of Ve was not consistent with that of de,max as the impact number increased.
The observed cleavage deformation is commonly observed for the many body centered cubic (bcc) metals or alloys, like 12Cr steel, with a few slip systems, which is usually initiated at grain boundaries and propagate rapidly across the specified crystallographic plane with a weak atomic bonding, i.e. (100) plane of the bcc structure [13,14].
It was found that the de,max increases stepwise-like with the number of impacts n, which results from a formation of craters due to a sudden crack propagation.
As the impact number increased further, the as-received 12Cr steel underwent a transition from ductile to brittle deformation due to a water drop impact induced work hardening.
Online since: February 2012
Authors: Shao Ke Chen
Timing control of the rolling angle of the stepping motor can control the number of space for blade hopper rotation and therefore realize quantitative control of the feeding amount.
Input of the number of days (D): First line on the LCD1602 shows the sample “Days input: (D)”; the first and second spaces in the second line can be filled in with a two-digit number of days, the data range of which is from “00~31” days.
The input of time t0~t4: it is the same as the input method of the number of days (D), except changing the menu requires one more key, K4.
The maximum number of input is 5000g.
If not, the number of days will be subtracted by 1 after the time accumulates to 24 hours.
Online since: May 2010
Authors: Vasilios Fourlakidis, Vasile Lucian Diaconu, Attila Diószegi
Microscopic analysis shows also a relation between the primary phase's fraction and the number of the eutectic cells.
Recently Rivera at al [9] showed that all the metallic phases corresponding to austenite grains have the same crystallographic orientation, including the embedded secondary austenite assumed to grow in collaboration with the eutectic graphite.
Number of eutectic cells vs.
Number of eutectic cells vs.
• The microstructure examination shows a clear relation between the number of eutectic cells and the amount of the primary phases.
Online since: June 2012
Authors: Xue Wu, Ci Yuan Xiao, Xue Yan Xu
Because there is always degree of membership in fuzzy comprehensive assessment , when using this operator to do fuzzy matrix synthesis , it must do transformation for membership matrix of assessment object , transform the value of membership to number larger than 1 , such as . 3) Multi-level non-linear fuzzy comprehensive assessment method The steps of multi-level non-linear fuzzy comprehensive assessment method are as follows: Step one : Divide factor set into factor sets according to some property , in which , and satisfy to : ① ; ② ; ③For any ,; Step two: For every factor set , do comprehensive assessment respectively .
If using linear fuzzy comprehensive assessment , there is Table 2 Separate results in oil&gas transmission pipeline fault tree quantitative analysis Serial number The basic event code(minimum cut set) The basic event name Probability importance degree Key importance degree 1 X14 Unreasonable design of strength 1.000 0.067022 2 X15 Improper material choice 1.000 0.067022 3 X16 Operator training 1.000 0.067022 4 X17 SCADA communication system 1.000 0.067022 5 X18 Equipment 1.000 0.067022 6 X19 Instrument 1.000 0.067022 7 X29 Uneven metallographic structure 1.000 0.067022 8 X30 Tube containing impurities 1.000 0.067022 9 X31 Coarse grains 1.000 0.067022 10 X35 Poor quality of pipeway 1.000 0.067022 11 X36 Mechanical damage 1.000 0.067022 12 X3 Layer moving near the pipe 1.000 0.031446 13 X4 Drilling , steal oil / gas 1.000 0.031446 14 X5 Enormous pressure on pipe in-line 1.000 0.031446 15 X22 Poor quality of anti-corrosion layer 1.000 0.031446 16 X32 Poor quality
Oil&gas transmission pipeline failure analysis Existed defects The third damage Incorrect operation Drilling, steal oil/ gas Layer moving near the pipe Enormous pressure on pipe in-line Improper material choice Unreasona-ble design of strength Operator training SCADA commu- nication system Equip- ment Instru- ment Poor quality of installation Poor quality of welding Mechanical damage Poor quality in process Poor quality of anti-corrosion layer Poor quality of pipeline Coarse grains Tube containing impurities Uneven metal graphic structure Figure 1 Oil&gas transmission pipeline failure comprehensive assessment indicator system Figure 2 and R
Online since: November 2012
Authors: Shi Xia Xiao, Yi Mei
Its inner texture is compact and grain is fine, and its mechanical strength, wear resistance and fatigue life are significantly higher than those produced by other methods.
For most wind power bearing in our country are produced by rectangular cross-section, there are some problems exist in the production, such as, low material utilization, long processing cycle, large number of cutting flow lines, low dimensional accuracy and weak stability of organization, not sure of residual stress state and machining deformation.
It has many outstanding problems, such as material utilization is low, long processing cycle, a large number of flow lines cut, dimensional accuracy and the performance stability is not strong, the residual stress state and processing deformation are of uncertainty.
Heat treatment is used to eliminate residual stress, especially after higher temperature annealing, although the residual stress is removed, the product's grain grow significantly, and it is detrimental to the mechanical properties of the metal[1,3].
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