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SPARK PLASMA SINTERING OF BALL MILLED AND ATOMIZED POWDER BASED ON Fe-Al
Šíma, V.; Minárik, P.; Chráska, Tomáš
2015 - anglický
High-quality compacts were prepared using the spark plasma sintering (SPS) method from powders of similar composition Fe-Al-Zr-B. The properties of the sintered compacts are strongly dependent on the morphology and properties of the feedstock powder. The first powder was obtained by ball milling of the as cast alloy and the second was prepared by atomization under argon atmosphere. The morphology and structure of the two powders are compared and mechanical properties and microstructure of compacts prepared under the same conditions of the SPS procedure are discussed. The milled powder has an irregular morphology and shape of the polycrystalline particles, which have a completely disordered BCC structure with considerable internal stresses, high concentration of structural defects and the presence of aluminum oxide. The atomized powder particles are nearly spherical, polycrystalline with ordered B2 structure, with no significant signs of internal stresses and oxidation. Microhardness of particles of both powders was measured and compared with the microhardness of compact materials, the results of compression tests of compacts at room temperature were compared and discussed.
Klíčová slova:
Iron aluminides; spark plasma sintering; metallic powders; mechanical properties; microstructure
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
SPARK PLASMA SINTERING OF BALL MILLED AND ATOMIZED POWDER BASED ON Fe-Al
High-quality compacts were prepared using the spark plasma sintering (SPS) method from powders of similar composition Fe-Al-Zr-B. The properties of the sintered compacts are strongly dependent on the ...
Investigation of Anode Attachment Area in Water/Argon Stabilized Plasma Arc
Ondáč, Peter; Mašláni, Alan; Hrabovský, Milan
2015 - anglický
Arc-anode attachment in a DC plasma arc stabilized by water vortex and argon, influences power distribution in the plasma, lifetime of the anode and also flow structure of the plasma jet. A movement of the attachment and the surrounding plasma has been directly observed by using a high-speed camera (max. 1,080,000 fps). The observations were compared with cathode–anode voltage measurements (sample rate 80 MHz). More than one attachment was observed in one frame with exposure time 0.25 μs or 0.29 μs. We have directly measured average velocities of the attachments and hydrodynamic waves above them, as well as the characteristic dwell times and dwell frequencies of the attachments
Klíčová slova:
Arc-anode; plasma arc
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Investigation of Anode Attachment Area in Water/Argon Stabilized Plasma Arc
Arc-anode attachment in a DC plasma arc stabilized by water vortex and argon, influences power distribution in the plasma, lifetime of the anode and also flow structure of the plasma jet. A movement ...
TOMOGRAPHICAL APPROACH IN 3-D TEMEPEARTURE DISTRIBUTION MEASUREMENT BY DIGITAL HOLOGRAPHY
Psota, Pavel; Doleček, Roman; Lédl, Vít; Vojtíšek, Petr; Vít, T.; Matoušek, Ondřej
2015 - anglický
This paper presents a digital holographic method for measurement and visualization of temperature distribution in 3-D space. It is based on measurement of phase information along various projections followed by a tomographic reconstruction of the 3-D temperature distribution. The method is experimentally proved and some results are presented in this paper.
Klíčová slova:
digital holography; holographic interferometry; temperature; 3-D measurement; tomography
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
TOMOGRAPHICAL APPROACH IN 3-D TEMEPEARTURE DISTRIBUTION MEASUREMENT BY DIGITAL HOLOGRAPHY
This paper presents a digital holographic method for measurement and visualization of temperature distribution in 3-D space. It is based on measurement of phase information along various projections ...
Chemical aspects of antiballistic cermets preparation
Brožek, Vlastimil; Kubatík, Tomáš František; Chráska, Tomáš; Mušálek, Radek; Janata, Marek; Mastný, L.
2015 - anglický
The paper aims to demonstrate the possibilities of metal-ceramic material deposition on different types of metal or ceramic substrates using plasma deposition. A number of self-supporting components and the preparation of metal-braced composites are described and the results of plasma depositions of two particular extremely hard ceramic materials, boride and nitride of titanium are presented. The plasma deposition of these material is performed in technological conditions which prevent undesirable high-temperature oxidation. The paper describes deposition conditions that may lead to materials suited to create anti-ballistic protection and complicated shapes or improve parameters of surface layers of present anti-ballistic ceramics.
Klíčová slova:
Anti-ballistic ceramics; armour ceramics; plasma spraying; titanium boride; plasma spraying; titanium nitride
Dokument je dostupný na externích webových stránkách.
Chemical aspects of antiballistic cermets preparation
The paper aims to demonstrate the possibilities of metal-ceramic material deposition on different types of metal or ceramic substrates using plasma deposition. A number of self-supporting components ...
Mechanical and chemical properties of plasma sprayed bronze CuAl10 coating on magnesium and magnesium alloy AZ91
Kubatík, Tomáš František; Vilémová, Monika; Mušálek, Radek; Janata, Marek
2015 - anglický
The most common magnesium alloy AZ91 is widely used as a structural material, but its use is limited at higher temperatures and high humidity. Plasma spraying is a technology that allows to prepare protective metallic and nonmetallic coatings on a wide variety of substrates including magnesium and its alloys. In this study, CuAl10 was plasma sprayed on magnesium and magnesium alloy AZ91 with the aim to study corrosion resistance of the magnesium substrates. The work focuses on optimization of the plasma spraying process, on chemical composition of the coatings, on interface between the coating and substrate, as well as on adhesive strength of the coatings. The coating were deposited after two passes of the spraying torch resulting in thickness of 150 micro m on magnesium substrate and 110 micro m on AZ91 substrate. Chemical microanalysis showed that deposition of CuAl10 alloy on magnesium results in formation of an intermetallic layer at the interface. The layer provides a
Klíčová slova:
Magnesium alloy AZ91; Plasma spraying
Dokument je dostupný na externích webových stránkách.
Mechanical and chemical properties of plasma sprayed bronze CuAl10 coating on magnesium and magnesium alloy AZ91
The most common magnesium alloy AZ91 is widely used as a structural material, but its use is limited at higher temperatures and high humidity. Plasma spraying is a technology that allows to prepare ...
Structural and Mechanical Characterization of Spark Plasma Sintered Tungsten
Čech, J.; Haušild, P.; Kocmanová, Lenka; Matějíček, Jiří
2015 - anglický
The main objective of this paper is to describe the microstructure and mechanical properties of spark plasma sintered tungsten. The indentation tests, which are very advantageous because of their semi-nondestructive character and low requirements on the volume of investigated material, were carried out using Berkovich and spherical indenters. Indentation techniques with spherical indenters are less frequently used than those with sharp indenters but they offer variation of strain with the indentation depth and, therefore, they could be used for determination of stress-strain curves. Local stress-strain behavior obtained by this method showed good correspondence with the results of compression tests. Observation of the microstructure and the fracture surfaces helped to explain some phenomena which occurred during the mechanical testing
Klíčová slova:
tungsten; SPS; instrumented indentation
Dokument je dostupný na externích webových stránkách.
Structural and Mechanical Characterization of Spark Plasma Sintered Tungsten
The main objective of this paper is to describe the microstructure and mechanical properties of spark plasma sintered tungsten. The indentation tests, which are very advantageous because of their ...
Deposition of Fluorocarbon Plasma Polymer Nanoparticles and their Basic Properties
Serov, Anton; Choukourov, A.; Artemenko, A.; Kuzminova, A.; Biederman, H.; Hrabovský, Milan
2015 - anglický
Fluorocarbon plasma polymer nanoparticles have been fabricated using gas aggregation cluster source (GAS) equipped with a planar magnetron with PTFE target. A beam of nanoparticles 20 – 200 nm in diameter was generated. Fluorocarbon nanoparticle films have shown very good water repellent properties. Films immersed in ethanol for two hours exhibited excellent stability that was also good in case of water. Measurements using a deflection system showed the presence of both neutral and charged nanoparticles.
Klíčová slova:
poly(tetrafluoroethylene); magnetron sputtering; plasma polymerization; superhydrophobic
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Deposition of Fluorocarbon Plasma Polymer Nanoparticles and their Basic Properties
Fluorocarbon plasma polymer nanoparticles have been fabricated using gas aggregation cluster source (GAS) equipped with a planar magnetron with PTFE target. A beam of nanoparticles 20 – 200 nm in ...
Nanostructuring of solid surfaces by discharge-pumped xuv laser source
Schmidt, Jiří; Štraus, Jaroslav; Koláček, Karel; Frolov, Oleksandr
2015 - anglický
The experimental results of interaction of focused XUV laser beam (wavelength 46.9 nm) with Polymethylmethacrylate (PMMA) and GaAs samples will be presented. Proximity-standing golden grid showed on naturally-generated diffraction pattern that direct nanostructuring is possible
Klíčová slova:
XUV laser; laser ablation; diffraction pattern
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Nanostructuring of solid surfaces by discharge-pumped xuv laser source
The experimental results of interaction of focused XUV laser beam (wavelength 46.9 nm) with Polymethylmethacrylate (PMMA) and GaAs samples will be presented. Proximity-standing golden grid showed on ...
Measurements with Atomic Beam Probe Diagnostic on the COMPASS Tokamak
Háček, Pavel; Berta, Miklós; Krbec, Jaroslav; Stöckel, Jan; Weinzettl, Vladimír; Bencze, A.; Zoletnik, S.; Anda, G.
2015 - anglický
Atomic beam probe is a new diagnostic method for detection of ions coming from the ionized part of diagnostic neutral beams in tokamaks. The method allows to measure plasma density fluctuations and fast variations in the poloidal magnetic field. Therefore, one can follow fast changes in the edge plasma current. Test detector has been installed on COMPASS as an extension of lithium beam diagnostic and the article presents the first measurements done with the diagnostic
Klíčová slova:
plasma; tokamak; diagnostic
Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Measurements with Atomic Beam Probe Diagnostic on the COMPASS Tokamak
Atomic beam probe is a new diagnostic method for detection of ions coming from the ionized part of diagnostic neutral beams in tokamaks. The method allows to measure plasma density fluctuations and ...
Unfolding of energies of fusion products measured by the activation probe at JET
Ficker, Ondřej; Mlynář, Jan; Bonheure, G.; Murari, A.; Popovichev, S.
2015 - anglický
Providing a detection method for diagnostic of charged fusion products in tokamaks presents a major challenge, while its absolute calibration with a sufficient accuracy and its capability to withstand harsh fusion reactor environment will be required. A novel type of detector that meets most of these requirements, based on an activation probe, was tested in JET and other European facilities. This probe proved to be extremely robust due to its simple construction. It is equipped with samples of well defined isotopic abundance. The amounts of activated nuclei due to the reactions in these materials could be measured via ultra-low-level gamma spectroscopy. The feasibility of the proton spectrum reconstruction from measured activities is examined in this contribution with the help of the algorithm based on the Tikhonov regularisation constrained by minimum Fisher information. The reliability of the method was previously illustrated using synthetic proton data.
Klíčová slova:
fusion products; nuclear activation; protons; spectra
Dokument je dostupný na externích webových stránkách.
Unfolding of energies of fusion products measured by the activation probe at JET
Providing a detection method for diagnostic of charged fusion products in tokamaks presents a major challenge, while its absolute calibration with a sufficient accuracy and its capability to withstand ...
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