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Tytuł:
High Energy Ball Milling of YAG Powders: Sintering Properties and Microstructural Evaluation
Autorzy:
Ozer, A.
Kilic, O.
Powiązania:
https://bibliotekanauki.pl/articles/1030279.pdf
Data publikacji:
2017-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.20.Ev
Opis:
Outstanding properties of sintered ceramics due to lower sintering temperatures and smaller grain sizes are of much attention to many researchers. In this study, YAG phase was formed successfully with mechanical activation of powder mixtures by high energy ball milling of powders at different speeds. The powders were compacted and sintered at three different temperatures to evaluate the sintering density, phase formation and grain formation. It was found that increasing activation time, which agitates the powder mixing more accurately, has led to an increase in the relative density, as compared to non-activated samples, sintered at same temperatures. Up to 95% ot the theoretical density were reached, indicating the partial liquid phase formation of Y-A related phases. YAG phase formation and crystallite size were evaluated using XRD and Debye-Scherrer formula. The studies of grain size and surface morphology were conducted using SEM. Since the mechanical activation of ceramic powders occurs by fragmentation and crack propagation, by brittle fracture of powders, the main mechanism of reduction of sintering temperature can be concluded to be the decreasing grain size, as well as the increasing strain on fine powder grains.
Źródło:
Acta Physica Polonica A; 2017, 131, 3; 329-331
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Effect of Milling Speed on Particle Size and Morphology of Cu25W Composite Powder
Autorzy:
Biyik, S.
Aydin, M.
Powiązania:
https://bibliotekanauki.pl/articles/1194030.pdf
Data publikacji:
2015-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.20.Ev
Opis:
In this study, the effect of milling speed on particle size and morphology of Cu25W composite powder produced by high-energy ball milling was investigated. For this aim, commercial elemental copper and tungsten powders were milled in a planetary-type ball mill for different milling durations. Ball-to-powder weight ratio was selected as 10:1. Three different milling speeds, namely 200, 300, and 400 rpm were used throughout the tests. In order to avoid agglomeration and to decrease the tendency of cold welding among powder particles, stearic acid in amount of 2 wt.% was used as a process control agent. The morphological and microstructural evolution of the milled powders was evaluated by scanning electron microscopy. In addition, the variation of particle size and powder morphology as a function of milling duration was determined. As a result of this effort, the milling duration was found to have strong effect on the structural evolution of the powder, and the optimum particle size as a function of milling speed was determined.
Źródło:
Acta Physica Polonica A; 2015, 127, 4; 1255-1260
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spark Plasma Sintering of Boron Carbide Ceramics Using Metallic Silicon in Square Cross Section
Autorzy:
Cengiz, M.
Sahin, F.
Powiązania:
https://bibliotekanauki.pl/articles/1401426.pdf
Data publikacji:
2015-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.20.Ev
Opis:
B₄C ceramics were fabricated by spark plasma sintering (SPS) technique with 5 vol.% silicon as sintering additive. Optimization of SPS method production parameters for B₄C ceramics having geometries 50×50×5 mm, square cross section will be performed. The sintering process was carried out at different temperatures by applying 40 MPa of pressure under vacuum atmosphere. The effect of silicon additive, sintering temperature and different soaking times on density, vickers hardness, fracture toughness and microstructure were examined. The mechanical properties of the B₄C ceramics having silicon as additive were compared with the results of monolithic B₄C. The hardness and fracture toughness of the samples were evaluated by the vickers indentation technique. Microstructures of spark plasma sintered B₄C samples with different parameters in square cross section were characterized by using SEM technique.
Źródło:
Acta Physica Polonica A; 2015, 127, 4; 1370-1372
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Characterization Investigations of W-Ni Matrix Composites Reinforced with $TiB_2$ and $La_2O_3$
Autorzy:
Gökçe, H.
Balcı, Ö.
Ağaoğulları, D.
Demirkan, Ö.
Genç, A.
Öveçoğlu, M.
Duman, İ.
Powiązania:
https://bibliotekanauki.pl/articles/1399817.pdf
Data publikacji:
2013-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.20.Ev
Opis:
W-1 wt% Ni (W1Ni) matrix composites reinforced with $TiB_2$ and $La_2O_3$ particles were fabricated via mechanical alloying and activated sintering methods. Powder blends with compositions of W1Ni-2 wt% TiB_2-x wt% $La_2O_3$ (x = 0.5, 1) were mechanically alloyed for 6 and 12 h. The results showed that increase in mechanical alloying duration to 12 h causes the decline of grain sizes of the W-Ni matrix to nanoscales. $TiB_2//La_2O_3$ particles have a significant effect on the density/microhardness values and wear amounts of the sintered samples.
Źródło:
Acta Physica Polonica A; 2013, 123, 2; 309-312
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fabrication, Structure and Consolidation of NiAl-Al$\text{}_{2}$O$\text{}_{3}$ Mechanically Alloyed Nanocomposite Powders
Autorzy:
Oleszak, D.
Michalski, A.
Majewski, T.
Powiązania:
https://bibliotekanauki.pl/articles/2035470.pdf
Data publikacji:
2002-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.20.Ev
Opis:
Reactive milling of NiO + Al powder mixture resulted in the formation of NiAl-Al$\text{}_{2}$O$\text{}_{3}$ nanocomposite powders, with a crystallite size of about 20 nm. The Hall-Williamson analysis revealed that NiAl showed an orientation dependent crystallite size after short processing time and orientation dependent internal strain after long milling time. Both anisotropies were removed by heating the powders in the differential scanning calorimetry. Calorimetric studies showed one exothermic effect attributed to the reduction reaction of NiO and endothermic one associated with melting of Al. Two methods were applied for powders compaction: resistance sintering and pulse electric discharge. In both cases the densities of about 90% of the theoretical value were achieved. A significant increase in average NiAl crystallites size in compacted samples was observed, up to several hundreds of nanometers.
Źródło:
Acta Physica Polonica A; 2002, 102, 2; 187-192
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Sintering Time on Hardness and Wear Behaviours of Carbon Nanotubes Reinforced Aluminium Matrix Composites
Autorzy:
Yildirim, M.
Ozyurek, D.
Guru, M.
Powiązania:
https://bibliotekanauki.pl/articles/1033387.pdf
Data publikacji:
2017-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.20.Ev
Opis:
In this study, the effects of sintering time on hardness and wear behaviour were investigated of carbon nanotubes reinforced aluminium matrix composites. 1% multi wall carbon nanotubes (90% purity with 9.5 nm in diameter, 1.5 μm in length) and gas atomized 7075 Al alloy powders were mechanical milled for 120 min in a planetary ball mill. Mechanical milled aluminium composite powders were cold pressed under 520 MPa. Pre-shaped samples were sintered in atmosphere controlled furnace at 580°C for three different sintering times (1, 2, and 3 h). As a result of study, it was observed that the hardness values of composites were decreased with increasing sintering time and the weight loss was decreased. It was determined from worn surface SEM images that adhesive wear mechanisms were dominant.
Źródło:
Acta Physica Polonica A; 2017, 131, 1; 92-95
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fabrication and Characterisation of Bronze Pads and Comparison with Commercial Bronze Pads
Autorzy:
Demir, A.
Powiązania:
https://bibliotekanauki.pl/articles/1185359.pdf
Data publikacji:
2016-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.20.Ev
Opis:
CuSn10 pre-alloyed bronze with iron and graphite powders were mixed, pressed and sintered for the bronze pad fabrication. The powder mix was pressed under pressure in the range of 100-600 MPa and sintered at temperatures between 780-850°C. The optimum compression was at 500 MPa and the optimal sintering temperatures was 730°C. 2 wt.% of graphite addition was sufficient to adjust the friction and wear properties of produced bronze pad samples. Optical microscope and SEM images showed that a homogenous powder mix was achieved. The produced bronze samples and the commercial ones were compared and beneficial properties of them were determined. The wear behaviours of both the produced friction materials and the commercial pads were examined. The coefficient of friction and wear rates were determined. The sintered bronze samples and the commercial bronze pads have exhibited similar wear behaviour, although the commercial one have contained ceramic particles.
Źródło:
Acta Physica Polonica A; 2016, 129, 4; 880-882
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Controlling a robot swarm with EV3 modules for mobile indoor mapping
Autorzy:
Pawłowicz, B.
Sierpiński, M.
Trybus, B.
Powiązania:
https://bibliotekanauki.pl/articles/114160.pdf
Data publikacji:
2016
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
robot swarm
RFID
WinRT
EV3
Opis:
The goal of the paper is to present a lab application controlling a swarm of mobile robots built with Lego Mindstorms bricks of EV3 series. The application named BrickCenter is based on Windows Runtime (WinRT) architecture and allows the user to manage robots by controlling selected motors through a keyboard or a gamepad. The application is able to read measurements acquired from standard sensors connected to EV3 controllers. It is a basis for a concept of supervisory control of a robot swarm designed for indoor mapping with RFID readers.
Źródło:
Measurement Automation Monitoring; 2016, 62, 8; 274-277
2450-2855
Pojawia się w:
Measurement Automation Monitoring
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Spark Plasma Sintering of Silicon Carbide Ceramics Using Alumina
Autorzy:
Unlu, M.
Goller, G.
Yucel, O.
Sahin, F.
Powiązania:
https://bibliotekanauki.pl/articles/1216300.pdf
Data publikacji:
2014-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.20.Ev
81.05.Je
Opis:
SiC ceramics were fabricated by spark plasma sintering technique with the use of $Al_2O_3$ additive. The sintering process was carried out at three different temperatures in the range of 1700-1800C applying two different pressures 40 and 80 MPa under vacuum atmosphere. The effect of additive, different temperatures and pressures on densification behaviour, density, Vickers hardness, fracture toughness, and microstructure were examined. The hardness and fracture toughness of the samples were evaluated by the Vickers indentation technique. Microstructure of spark plasma sintered SiC samples were characterized by using scanning electron microscopy technique. The highest value of fracture toughness $5.9 ± 0.2$ MPa $m^{1/2}$ was achieved with the addition of 5 vol.% $Al_2O_3$.
Źródło:
Acta Physica Polonica A; 2014, 125, 2; 257-259
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Characterization of CoTi Intermetallic Materials Produced by Electric Current Activated Sintering
Autorzy:
Ergin, N.
Ozdemir, O.
Powiązania:
https://bibliotekanauki.pl/articles/1219351.pdf
Data publikacji:
2014-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.20.Ev
81.40.Pq
Opis:
In the present work, the characterization and production of CoTi intermetallic materials produced by electric current activated sintering under 300 MPa uniaxial pressure in open air at 2000 A for 6 min was investigated. Cobalt powder with 10 μm size and titanium powder < 40 μm size having 99.9% and 99.5% purity, respectively, were used. The elemental powders were mixed in the stoichiometric ratio corresponding to the CoTi intermetallic, in a molar proportion of 1:1. Scanning electron microscopy and X-ray diffraction analysis were used to characterize produced samples. In microstructural examinations it was found that the sample has multi-phase microstructure. X-ray diffraction studies revealed that the phases are CoTi, $CoTi_2$, $TiCo_2$, and $CoTiO_3$. The relative density of test materials measured according to Archimedes' principle was 87.6%, and the microhardness of materials was about 646.74 $HV_{0.1}$.
Źródło:
Acta Physica Polonica A; 2014, 125, 2; 399-401
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Copper Addition on Pitting Corrosion of MA-Al
Autorzy:
Aranda, B.
Cuevas, F.
Cintas, J.
Herrera-García, M.
Urban, P.
Powiązania:
https://bibliotekanauki.pl/articles/1191707.pdf
Data publikacji:
2016-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.20.Ev
82.45.Bb
Opis:
This paper is intended to highlight the effect of copper addition on the pitting corrosion resistance of aluminium-base powder metallurgy parts. Results obtained on these mechanically alloyed (MA) specimens are compared with parts of MA-Al without added copper, as well as with commercial aluminium alloys. Immersion tests from 2 to 96 hours in 3.5% NaCl solutions, and potentiostatic techniques, were used to study the pitting corrosion. It was concluded that copper addition, in a similar way that in commercial aluminium alloys, produces a negative effect on the pitting corrosion resistance, because of the formation of Al₂Cu. These precipitates produce galvanic cells that favour the specimen pit. Therefore, increasing the copper content of MA-Al, although improving their ductility, worsens the pitting corrosion resistance of these alloys.
Źródło:
Acta Physica Polonica A; 2016, 129, 4; 788-791
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Theoretical and Experimental Determination of the Sound-Absorbing Property Class of Acoustic Barriers
Autorzy:
Turkiewicz, J.
Wszołek, G.
Powiązania:
https://bibliotekanauki.pl/articles/1359889.pdf
Data publikacji:
2014-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
43.55.Ev
43.50.Gf
Opis:
The currently applicable PN-EN 1793-1 standard concerning anti-noise devices on roads recommends for acoustic barriers built along traffic routes to have panels characterized by good sound-absorbing properties. The sound-absorbing properties of these panels (wall elements) are to be specified by giving the values of the single-number sound absorption evaluation index $DL_α$ and the absorption property class determined in accordance with the PN-EN 1793-3:2001 standard. Continuous regular acoustic studies of new materials heretofore not used in anti-noise protections are conducted in the Department of Mechanics and Vibroacoustics at AGH. This paper presents the findings of research that started with different porous materials physical absorption coefficient tests. The purpose of these preliminary tests was to pick out materials with best sound-absorbing properties from the group of acoustically tested materials. The chosen materials could be used as a sound-absorbing lining on panels (wall elements) used in the design of acoustic barriers. On the basis of the obtained results, two materials with values of the average physical sound absorption coefficient higher than 0.5 ($α_{favg}$>0.5) were picked out for further acoustic tests. This paper presents results of studies that had the final effect consisting in determining the values of the single-number sound absorption evaluation index $DL_α$ and the absorption property class for two prototype panels of an acoustic barrier the sound-absorbing lining of which was made up of materials chosen after preliminary acoustic studies. The determination of sound-absorbing property classes was carried out both theoretically and experimentally. In order to be possible to reduce the costs of acoustic tests in the future, particularly of new materials in regard to which there is a margin of uncertainty of whether their sound-absorbing properties meet expectations, the authors determined sound-absorbing property classes of acoustic barriers theoretically and then compared theoretical results with the results of experimental tests.
Źródło:
Acta Physica Polonica A; 2014, 125, 4A; A-127-A-130
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Microstructure, Thermal and Mechanical Properties of Non-Isothermally Annealed Al-Sc-Zr and Al-Mn-Sc-Zr Alloys Prepared by Powder Metallurgy
Autorzy:
Vlach, M.
Stulíková, I.
Smola, B.
Císařová, H.
Piešová, J.
Daniš, S.
Gemma, R.
Tanprayoon, D.
Neubert, V.
Powiązania:
https://bibliotekanauki.pl/articles/1418427.pdf
Data publikacji:
2012-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.20.Ev
81.30.Mh
Opis:
This paper reports results of a study aimed at understanding the precipitation processes occurring during the annealing of two Al-Sc-Zr-based alloys with and without Mn prepared by powder metallurgy with subsequent hot extrusion at 350°C. Samples were isochronally annealed up to ≈ 570°C. Precipitation behaviour was studied by electrical resistometry and differential scanning calorimetry. Mechanical properties were monitored by microhardness HV1 measurements. Transmission electron microscopy examinations and X-ray diffraction of specimens quenched from temperatures of significant resistivity changes helped to identify the microstructural processes responsible for these changes. Fine (sub)grain structure develops and fine coherent $Al_3Sc$ and/or $Al_3(Sc,Zr)$ particles precipitate during extrusion in both alloys. The distinct changes in resistivity (at temperatures above ≈ 330°C) of the Al-Mn-Sc-Zr alloy are mainly caused by precipitation of Mn-containing particles. The easier diffusion of Mn atoms along the (sub)grain boundaries is responsible for the precipitation of the $Al_6Mn$ and/or $Al_6(Mn,Fe)$ particles at relatively lower temperatures compared to the temperature range of precipitation of these particles in the classical mould-cast Al-Mn-Sc-Zr alloys The apparent activation energy for precipitation of the $Al_3Sc$ and $Al_6Mn$ particles in the Al-Mn-Sc-Zr alloy was determined as (106 ± 10) kJ $mol^{-1}$ and (152 ± 33) kJ $mol^{-1}$, respectively.
Źródło:
Acta Physica Polonica A; 2012, 122, 3; 439-443
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of SiC Particle Size on Properties of Cu-SiC Metal Matrix Composites
Autorzy:
Celebi Efe, G.
Altinsoy, I.
Ipek, M.
Zeytin, S.
Bindal, C.
Powiązania:
https://bibliotekanauki.pl/articles/1491445.pdf
Data publikacji:
2012-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Ni
81.20.Ev
Opis:
This paper was focused on the effects of particle size and distribution on some properties of the SiC particle reinforced Cu composites. Copper powder produced by cementation method was reinforced with SiC particles having 1 and 30 μm particle size and sintered at 700°C. Scanning electron microscopy studies showed that SiC particles were dispersed in copper matrix homogeneously. The presence of Cu and SiC components in composites were verified by X-ray diffraction analysis technique. The relative densities of Cu-SiC composites determined by Archimedes' principle are ranged from 96.2% to 90.9% for SiC with 1 μm particle size, 97.0% to 95.0% for SiC with 30 μm particle size. Measured hardness of sintered compacts varied from 130 to 155 HVN for SiC having 1 μm particle size, 188 to 229 HVN for SiC having 30 μm particle size. Maximum electrical conductivity of test materials was obtained as 80.0% IACS (international annealed copper standard) for SiC with 1 μm particle size and 83.0% IACS for SiC with 30 μm particle size.
Źródło:
Acta Physica Polonica A; 2012, 121, 1; 251-253
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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