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Youngův modul na rozhraní elastického a elastoplastického materiálu
Kocmanová, Lenka; Haušild, P.; Materna, A.; Matějíček, Jiří
2015 - Czech
Příspěvek je zaměřený na určování Youngova modulu na ostrém rozhraní mezi dvěma materiály, kde jeden materiál je elastický a druhý elasto-plastický. K určení Youngova modulu byl použit 3D numerický model nanoindentace s kuželovým indentorem. Rozhraní mezi materiály je rovina s normálou kolmou ke směru vtisku. Cílem je simulovat spojení kovových a keramických materiálů.\nHodnoty Youngova modulu v závislosti na normované vzdálenosti od rozhraní jsou aproximovány inverzní beta distribucí a je určena závislost parametrů inverzní beta distribuce na velikost oblasti ovlivněné druhou fází. \n The paper is aimed at determining the Young's modulus at the sharp interface between two materials, where one material is elastic and the other elastic-plastic. To determine the Young's modulus was used 3D numerical model of nanoindentation with conical indenter. The interface between the materials with the normal plane perpendicular to the direction of penetration. The goal is to simulate the combination of metal and ceramic materials.\n Young modulus according to the standardized distance from the interface are approximated inverse beta distribution and is determined by the relation between parameters inverse beta distribution of the size of the area affected by the second phase
Keywords:
instrumented indentation; tungsten; steel; composites; finite element modelling
Available at various institutes of the ASCR
Youngův modul na rozhraní elastického a elastoplastického materiálu
Příspěvek je zaměřený na určování Youngova modulu na ostrém rozhraní mezi dvěma materiály, kde jeden materiál je elastický a druhý elasto-plastický. K určení Youngova modulu byl použit 3D numerický ...
Synthesis and applications of Intermetallics
Novák, P.; Salvetr, P.; Kříž, J.; Kubatík, Tomáš František
2015 - English
Intermetallic compounds, intermetallics, are characterized by interesting properties, such as e.g. excellent high -temperature oxidation resistance, shape memory or ability to store hydrogen reversibly. Their positive, but also negative, properties are a combination of the behaviour of metals and ceramics. Their wider application in industry is limited due to low room-temperature ductility and problematic production, associated with high melting points of many intermetallics, high reactivity of metals at high temperatures and problematic processing. In this paper, the overview of the methods for synthesis of intermetallic compounds is presented, ranging from conventional casting processes to modern powder metallurgy technologies. Selected interesting applications from industry and medicine, where their unique properties are used
Keywords:
Intermetallic compounds; powder metallurgy technologies
Fulltext is available at external website.
Synthesis and applications of Intermetallics
Intermetallic compounds, intermetallics, are characterized by interesting properties, such as e.g. excellent high -temperature oxidation resistance, shape memory or ability to store hydrogen ...
SPARK PLASMA SINTERING OF BALL MILLED AND ATOMIZED POWDER BASED ON Fe-Al
Šíma, V.; Minárik, P.; Chráska, Tomáš
2015 - English
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.
Keywords:
Iron aluminides; spark plasma sintering; metallic powders; mechanical properties; microstructure
Available at various institutes of the ASCR
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 - English
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
Keywords:
Arc-anode; plasma arc
Available at various institutes of the ASCR
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 - English
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.
Keywords:
digital holography; holographic interferometry; temperature; 3-D measurement; tomography
Available at various institutes of the ASCR
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 - English
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.
Keywords:
Anti-ballistic ceramics; armour ceramics; plasma spraying; titanium boride; plasma spraying; titanium nitride
Fulltext is available at external website.
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 - English
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
Keywords:
Magnesium alloy AZ91; Plasma spraying
Fulltext is available at external website.
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 - English
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
Keywords:
tungsten; SPS; instrumented indentation
Fulltext is available at external website.
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 ...
Optické parametry objektivu Secrétan Paris 130/1930 Hvězdárny v Úpici.
Rail, Zdeněk; Melich, Zbyněk
2015 - Czech
Objektiv Secrétan Paris 130/1930 Hvězdárny v Úpici byl na pracovišti ÚFP AV ČR, v.v.i.- TOPTEC vyčištěn a byly proměřeny jeho optické parametry. V referátu uvádíme výsledky matematické simulace zbytkových vad objektivu. The Optical Parameters of Objective Lens Secrétan Paris 130/1930 of Observatory of Úpice Objective lens of Secrétan Paris 130/1930 of Úpice observatory was cleaned a measured its optical parameters in IPP AS CR, v.v.i. - TOPTEC. In this paper we present results of mathematical simulation of residual aberrations of this lens.
Keywords:
Achromatic doublet; Antonín Bečvář; Chromatic aberration; Lens parameters; Residual optical aberrations; B-F type of chromatic correction; Uncorrected coma
Fulltext is available at external website.
Optické parametry objektivu Secrétan Paris 130/1930 Hvězdárny v Úpici.
Objektiv Secrétan Paris 130/1930 Hvězdárny v Úpici byl na pracovišti ÚFP AV ČR, v.v.i.- TOPTEC vyčištěn a byly proměřeny jeho optické parametry. V referátu uvádíme výsledky matematické simulace ...
Deposition of Fluorocarbon Plasma Polymer Nanoparticles and their Basic Properties
Serov, Anton; Choukourov, A.; Artemenko, A.; Kuzminova, A.; Biederman, H.; Hrabovský, Milan
2015 - English
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.
Keywords:
poly(tetrafluoroethylene); magnetron sputtering; plasma polymerization; superhydrophobic
Available at various institutes of the ASCR
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 ...
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