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Tytuł:
Corrosion Behaviour Correlation of the Secondary Aluminium Casts in Natural Atmosphere and Laboratory Conditions
Autorzy:
Kuchariková, L.
Liptáková, T.
Tillová, E.
Bonek, M.
Medvecká, D.
Powiązania:
https://bibliotekanauki.pl/articles/352248.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
secondary aluminium alloys
high Fe content
corrosion properties
natural atmosphere
Opis:
The secondary aluminium alloys are very important material in actual industry from economic and ecological point of view. The secondary aluminium used for production of casts, however, contains some elements, i.e. iron, – affecting physical, chemical and mechanical behaviour. The subject of our investigation has been corrosion behaviour in natural atmosphere of the hypoeutectic AlSi7Mg0.3 cast alloys with various content of iron, because the Fe content affects not only mechanical properties but corrosion resistance, as well. Three types of the AlSi7Mg0.3 cast alloys were exposed for 9 months in natural atmosphere and the measure of their degradation by corrosion was found by determination of the weight loss and the light microscopy. In addition, a scanning electron microscopy (SEM) analyses and evaluation of surface changes were used. The corrosion behaviour in natural atmosphere was compared to results of the carried out electrochemical and exposure laboratory experiments in chloride solutions.
Źródło:
Archives of Metallurgy and Materials; 2020, 65, 4; 1455-1462
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Properties and Morphology of Fly Ash Based Alkali Activated Material (AAM) Paste Under Steam Curing Condition
Autorzy:
Razak, Rafiza Abd
Izman, Sharifah Nur Syamimi Syed
Abdullah, Mohd Mustafa Al Bakri
Yahya, Zarina
Abdullah, Alida
Mohamed, Rosnita
Powiązania:
https://bibliotekanauki.pl/articles/28099518.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
alkali activated material
AAM
geopolymer
fly ash
steam-cured
high-Fe
Opis:
This paper details the properties, microstructures, and morphologies of the fly ash-based alkali-activated material (AAM), also known as geopolymers, under various steam curing temperatures. The steam curing temperature result in subsequent high strengths relative to average curing temperatures. However, detailed studies involving the use of steam curing for AAM remain scarce. The AAM paste was prepared by mixing fly ash with an alkali activator consisting of sodium silicate (Na2SiO3) and sodium hydroxide (NaOH). The sample was steam cured at 50°C, 60°C, 70°C, and 80°C, and the fresh paste was tested for its setting time. The sample also prepared for compressive strength, density, and water absorption testings. It was observed that the fastest time for the fly ash geopolymer to start hardening was at 80°C at only 10 minutes due to the elevated temperature quickening the hydration of the paste. The compressive strength of the AAM increased with increasing curing time from 3 days to 28 days. The AAM’s highest compressive strength was 61 MPa when the sample was steam cured at 50°C for 28 days. The density of AAM was determined to be ~2122 2187 kg/m3, while its water absorption was ~6.72-8.82%. The phase analyses showed the presence of quartz, srebrodolskite, fayalite, and hematite, which indirectly confirms Fe and Ca’s role in the hydration of AAM. The morphology of AAM steam-cured at 50°C showed small amounts of unreacted fly ash and a denser matrix, which resulted in high compressive strength.
Źródło:
Archives of Metallurgy and Materials; 2023, 68, 2; 785--789
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Diffusive and Displacive Phase Transformations in Nanocomposites under High Pressure Torsion
Autorzy:
Straumal, B.
Kilmametov, A.
Gornakova, A.
Mazilkin, A.
Baretzky, B.
Korneva, A.
Zięba, P.
Powiązania:
https://bibliotekanauki.pl/articles/356575.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
high-pressure torsion
Ti-Fe alloys
phase transitions
high-pressure phases
Opis:
The high-pressure torsion (HPT) of Ti-Fe alloys with different iron content has been studied at 7 GPa, 5 anvil rotations and rotation speed of 1 rpm. The alloys have been annealed before HPT in such a way that they contained different amounts of α/α' and β phases. In turn, the β phase contained different concentration of iron. The 5 anvil rotations correspond to the HPT steady-state and to the dynamic equilibrium between formation and annihilation of microstructure defects. HPT leads to the transformation of initial α/α' and β-phases into mixture of α and high-pressure ω-phase. The α → ω and β → ω phase transformations are martensitic, and certain orientation relationships exist between α and ω as well as β and ω phases. However, the composition of ω-phase is the same in all samples after HPT and does not depend on the composition of β-phase (which is different in different initial samples). Therefore, the martensitic (diffusionless) transformations are combined with a certain HPT-driven mass-transfer. We observed also that the structure and properties of phases (namely, α-Ti and ω-Ti) in the Ti – 2.2 wt. % Fe and Ti – 4 wt. % Fe alloys after HPT are equifinal and do not depend on the structure and properties of initial α'-Ti and β-Ti before HPT.
Źródło:
Archives of Metallurgy and Materials; 2019, 64, 2; 457-465
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
High temperature transformation of iron-bearing minerals in basalt: Mössbauer spectroscopy studies
Autorzy:
Kądziołka-Gaweł, Mariola
Wojtyniak, Marcin
Klimontko, Joanna
Powiązania:
https://bibliotekanauki.pl/articles/2086563.pdf
Data publikacji:
2022
Wydawca:
Polskie Towarzystwo Mineralogiczne
Tematy:
basalts
high temperature affects
Mössbauer spectroscopy
Fe-bearing minerals
Opis:
The high temperature decomposition of basalt from Lower Silesia (Poland) was followed by Mössbauer spectroscopy investigation. The Fe content of the sample was ~9.0 at.%. The X-ray diffraction analysis shows that augite (37%) and olivine (12%) are major Fe-bearing mineral components. The sample also contains significant amount of anorthite (22%) and nepheline (17%). The sample was heated at various temperatures between 200o C and 1100o C for three hours. Up to a temperature of 500o C changes in contribution of Fe-bearing minerals are insignificant. Heating in the temperature range from 500o C to 1100o C leads to a systematic increase in contribution of iron oxides at the cost of contribution of silicate minerals, like augite and olivine. Mössbauer spectrum obtained after heating at 1100o C showed hematite as the main iron oxide phase. The ratio of Fe3+/Fetot in the non-heated sample was equal to 0.51 and after heating at 1100o C this ratio amounted to 0.89.
Źródło:
Mineralogia; 2022, 53, 1; 10--19
1899-8291
1899-8526
Pojawia się w:
Mineralogia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wysokotemperaturowe siarkowanie stali typu Fe-Cr-Al: aktualny stan i perspektywy badań
High-temperature sulphidation of Fe-Cr-Al steels: the present state of the art and future research
Autorzy:
Homa, M
Powiązania:
https://bibliotekanauki.pl/articles/391735.pdf
Data publikacji:
2008
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Odlewnictwa
Tematy:
zgorzelina
siarczki
stale typu Fe-Cr-Al
siarkowanie
scale
sulfides
Fe-Cr-Al steels
high temperature sulfidatio
Opis:
Praca przedstawia krytyczną analizę obecnego stanu wiedzy na temat badań nad żaroodpornością stali typu Fe-Cr-Al z grupy AFA (Alumina Forming Alloys) w atmosferach siarkujących. Zachowanie się tych materiałów w środowisku gorących gazów jest od lat przedmiotem wnikliwych badań. W warunkach wysokotemperaturowego siarkowania w atmosferach takich, jak gazowa siarka, siarkowodór, gazy spalinowe, merkaptany i inne na powierzchni tych materiałów tworzą się wielowarstwowe zgorzeliny siarczkowe. Warstwy te ze względu na swoją budowę (pęknięcia, szczeliny oraz pustki na granicy zgorzelina/stal) wykazują słabe właściwości ochronne nie zabezpieczając stali przed dalszą degradacją. Skład chemiczny zgorzelin tworzących się w różnych atmosferach siarkowych jest podobny i najczęściej analiza rentgenowska wykazuje obecność siarczków chromu, żelaza oraz glinu, a także sulfospineli. Udział poszczególnych siarczków w poszczególnych warstwach, zależy od rodzaju medium siarkującego, temperatury i czasu ekspozycji oraz składu chemicznego siarkowanego materiału. Wzrost wielowarstwowych zgorzelin siarczkowych odbywa się na drodze odrdzeniowej dyfuzji kationów metalu (Fe, Cr, Al) w strukturze sieci krystalicznej oraz dordzeniowej dyfuzji siarki poprzez nieciągłości w strukturze warstwy.
This work reviews the current state of research regarding high temperature sulphidation resistance of Fe-Cr-Al steels that belong to a family of AFA (Alumina Forming Alloys). The behavior of these steels in hot gases environment (sulphur, H2S, combustion gases, mercaptans etc.) is a subject of intensive research. During high temperature sulphidation none-protective porous and cracking multilayer scale is formed on their surface. The chemical composition of this scales depends on atmosphere composition. Mostly, the XRD analysis shows that mainly the scales consist of iron, chromium, aluminum sulphides and sulfospinels. The amount of particular sulphides in particular layers depends on atmosphere, temperature, time of sulphidation and chemical composition of the material. The growth of multilayer scales take place by the outward diffusion of metal cations (Fe, Cr, Al) through the defects of the crystal lattice and inward diffusion of the sulphur through the discontinuities in the layer structure.
Źródło:
Prace Instytutu Odlewnictwa; 2008, 48, 4; 19-41
1899-2439
Pojawia się w:
Prace Instytutu Odlewnictwa
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Forming of the microstructure in Fe-C-V alloys
Kształtowanie mikrostruktury stopów Fe-C-V
Autorzy:
Kawalec, M.
Fraś, E.
Powiązania:
https://bibliotekanauki.pl/articles/264061.pdf
Data publikacji:
2011
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
stopy Fe-C-V
eutektyka
żeliwo wysokowanadowe
mikrostruktura
Fe-C-V alloys
eutectic
high-vanadium cast iron
microstructure
Opis:
The study presents the results of microstructural examinations of the volume solidifying Fe-C-V alloys containing carbon in the range of 1.45-2.23% and vanadium in the range of 7.33-15.08%. Attention was focussed on near-eutectic alloys. The Fe-C-V eutectic crystallising in these alloys is composed of ferrite and vanadium carbides of VC1-x type, and as such is included in the group of fibrous eutectics. During research, the experimental eutectic lines were plotted for Fe-C-V alloys, and a formula enabling calculation of the eutectic saturation ratio of these alloys was proposed.
W pracy przedstawiono wyniki badań mikrostruktury stopów Fe-C-V, o zawartości węgla w zakresie 1,45-2,23% i wanadu w zakresie 7,33-15,08%, krystalizujących w sposób objętościowy, przy czym szczególną uwagę zwrócono na stopy okołoeutektyczne. Krystalizująca w stopach Fe-C-V eutektyka składa się z ferrytu i węglików wanadu typu VC1-x i jest zaliczana do grupy eutektyk włóknistych. W pracy określono eksperymentalnie przebieg linii eutektycznej dla stopów Fe-C-V oraz wyznaczono zależność na stopień nasycenia eutektycznego dla tych stopów.
Źródło:
Metallurgy and Foundry Engineering; 2011, 37, 1; 17-24
1230-2325
2300-8377
Pojawia się w:
Metallurgy and Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fabrication of Fe-TiB2 Nanocomposites by Spark-Plasma Sintering of a (FeB, TiH2) Powder Mixture
Autorzy:
Huynh, X.-K.
Kim, B.-W.
Kim, J.-S.
Powiązania:
https://bibliotekanauki.pl/articles/351368.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Fe-TiB2 nanocomposite
mechanical activation
spark plasma sintering
self-propagating high-temperature synthesis reaction
Opis:
Fe-40wt% TiB2 nanocomposites were fabricated by mechanical activation and spark-plasma sintering of a powder mixture of iron boride (FeB) and titanium hydride (TiH2). The powder mixture of (FeB, TiH2) was prepared by high-energy ball milling in a planetary ball mill at 700 rpm for 3 h followed by spark-plasma sintering (SPS) at various conditions. Analysis of the change in relative sintered density and densification rate during sintering showed that a self-propagating high-temperature synthesis reaction occurs to form TiB2 from FeB and Ti. A sintered body with relative density higher than 98% was obtained after sintering at 1150°C for 5 and 15 min. The microstructural observation of sintered compacts with the use of FE-SEM and TEM revealed that ultrafine particulates with approximately 5 nm were evenly distributed in an Fe-matrix. A hardness value of 83 HRC was obtained, which is equivalent to that of conventional WC-20 Co systems.
Źródło:
Archives of Metallurgy and Materials; 2018, 63, 2; 1043-1047
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Crystallization of Eutectics in Fe-C-V-Si Alloys
Autorzy:
Kawalec, M
Powiązania:
https://bibliotekanauki.pl/articles/381286.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
theory of crystallization
Fe-C-V-Si alloys
high-vanadium cast iron
microstructure
eutectic grain
teoria krystalizacji
stopy Fe-C-V-Si
żeliwo wysokowanadowe
mikrostruktura
eutektyka
Opis:
This article addresses the results of microstructural examinations of the volume solidifying Fe–C–V–Si alloys containing carbon in the range of 1.39÷1.76%, vanadium in the range of 6.77÷7.77% and silicon in the range of 0.02÷3.10. The melting charge was Armco iron, ferro-vanadium with 81.7 wt.%V, spectrally pure graphite and technically pure silica. It was shown that with increasing the silicon content, the microstructure of the resulting alloy changing. These changes include both a matrix the shape of the primary carbides and type of crystallizing eutectic. In the studied alloys was observed following eutectic: fibrous (crystallize as non-faceted/ non-faceted eutectic), complex regular (crystallize as faceted/ non-faceted eutectic), spiral (crystallize as faceted/ faceted eutectic). The results illustrated by the images of the microstructures made with an optical microscope and a scanning electron microscope.
Źródło:
Archives of Foundry Engineering; 2014, 14, 1 spec.; 143-146
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The mechanism of $CaCO_3$ in the gas-based direct reduction of a high-phosphorus oolitic iron ore
Autorzy:
Wu, Shichao
Li, Zhengyao
Sun, Tichang
Kou, Jue
Xu, Chengyan
Powiązania:
https://bibliotekanauki.pl/articles/1446124.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
high-phosphorus oolitic iron ore
gas-based direct reduction
magnetic separation
$Fe_3PO_7$
$CaCO_3$
Opis:
Gas-based direct reduction and magnetic separation process was applied in treating a high-phosphorus oolitic iron ore, of which phosphorus mainly occured as $Fe_3PO_7$ and apatite. The mechanism of $CaCO_3$ was investigated using XRD, SEM-EDS, and mineral phase analysis. Results showed that when no CaCO3 was added, most of the iron minerals were reduced to metallic iron, while $Fe_3PO_7$ was reduced to elemental phosphorus and mixed with the metallic iron particles. When a small amount of $CaCO_3$ was added, $CaCO_3$ preferentially reacted with $SiO_2$, $Al_2O_3$ and other components, preventing them from reacting with FeO and resulting in the increase of iron recovery. When the amount of $CaCO_3$ reached 25%, apatite was produced from the reaction of CaO and $Fe_3PO_7$, which could be later removed by grinding and magnetic separation.
Źródło:
Physicochemical Problems of Mineral Processing; 2021, 57, 4; 117-124
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Corrosion Behavior of Hastelloy® C-2000® Ni-Cr-Mo-Fe Alloys in the Entrained-Flow Coal Gasification Syngas Plants
Autorzy:
Lee, Sungkyu
Kim, Min-Jung
Choi, Nuri
Hwang, Sang Yeon
Chung, Seok-Woo
Lee, Seung-Kong
Yun, Yongseung
Powiązania:
https://bibliotekanauki.pl/articles/352403.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
mixed oxidant corrosion
Hastelloy® C-2000® Ni-Cr-Mo-Fe alloy
coal gasification
high temperature halogencorrosion
hydrated chlorides
Opis:
A mechanistic exposure experiment was performed on the commercially available and welded Ni-Cr-Mo-Fe alloy samples used in the piping materials of the coal gasification pilot plant. Thermodynamic Ellingham-Pourbaix stability diagrams were constructed to provide insight into the mechanism of the observed corrosion behavior. The thermodynamic inference on the corrosion mechanism was supplemented with the morphological, compositional and microstructural analyses of the exposed samples using scanning electron microscopy, X-ray diffraction and energy-dispersive X-ray spectroscopy analyses. X-ray diffraction result revealed stable corrosion products of NiO, MoNi4 and Cr4.6 MoNi2.1 after accumulated total exposure duration of 139 h to the corrosive atmosphere. Scanning electron microscopy and energy-dispersive X-ray spectroscopy positively identified formation of rather continuous and adherent pre-oxidation corrosion products although extensively peeled-off oxides were finally observed as corrosion scales on the post-exposure alloy samples, which were attributed to the chlorination/oxidation into thin (spalled) oxides.
Źródło:
Archives of Metallurgy and Materials; 2020, 65, 2; 869-878
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Żaroodporność i żarowytrzymałość stali typu Fe-Cr-Al w warunkach utleniających; aktualny stan i perspektywy badań
High temperature behavior of Fe-Cr-Al steel under oxidizing conditions - a review
Autorzy:
Homa, M.
Powiązania:
https://bibliotekanauki.pl/articles/391670.pdf
Data publikacji:
2008
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Odlewnictwa
Tematy:
stal Fe-Cr-Al
wysokotemperaturowe utlenianie
zgorzelina Al2O3
transformacja fazowa
morfologia powierzchni
Fe-Cr-Al steel
high temperature oxidation
alumina scale
phase transformation
surface morphology
Opis:
Praca przedstawia krytyczną analizę obecnego stanu wiedzy na temat badań nad żaroodpornością stali typu Fe-Cr-Al z grupy AFA (Alumina Forming Alloys), których zachowanie w środowisku gorących gazów jest od lat przedmiotem wnikliwych badań. W warunkach wysokotemperaturowego utleniania tworzy się na ich powierzchni ochronna warstwa zgorzeliny zbudowana z tlenku glinu, który może występować w różnych odmianach krystalograficznych. Odmiany fazowe mogą ulegać transformacji od niestabilnej fazy γ poprzez δ i θ do stabilnej fazy α. O rodzaju utworzonej fazy decyduje temperatura procesu utleniania, skład atmosfery oraz czas. Przemianom fazowym tlenku glinu towarzyszy zmiana szybkości utleniania stali, ponieważ niestabilne tlenki wykazują wyższe szybkości narastania niż stabilny tlenek α-Al2O3. Dodatkowo w trakcie transformacji fazowej obserwuje się zmiany morfologii powierzchni tworzących się zgorzelin. Fazy przejściowe na ogół występują w postaci płytek, bardzo cienkich długich kryształów (whiskerów) oraz tworów blaszkowych, tworzących silnie rozwinięte powierzchnie, podczas gdy faza α wykazuje budowę kolumnową a utworzona z niej powierzchnia zgorzeliny jest pofałdowana.
This work reviews the current state of research regarding high temperature oxidation resistance of Fe-Cr-Al steels, that belong to a family of AFA (Alumina Forming Alloys). The behavior of these steels in hot gases environment is a subject of intensive research. During high temperature oxidation, the protective layer of alumina oxide is formed on their surface, which can have different crystallographic forms. Moreover, Al2O3 can transform from instable γ- phase to δ, θ and finally stable α-phase. The type of alumina depends on temperature, time and atmosphere composition. The phase transformation of aluminum oxide is accompanied with change of oxidation kinetics because instable oxides grow faster than unstable ones. Additionally, during phase transformation the morphology change of surfaces is observed. Instable phases have the form of platelets, very long thin crystals (whiskers) and blade-like crystals, in all cases resulting in the formation of highly developed scale surface. Stable α-phase shows columnar crystals construction with corresponding pleated scale surface.
Źródło:
Prace Instytutu Odlewnictwa; 2008, 48, 3; 57-85
1899-2439
Pojawia się w:
Prace Instytutu Odlewnictwa
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stop na bazie Fe-Al - aspekt technologiczny
Technological aspects of alloys based on the Fe-Al system
Autorzy:
Jaśkowiec, K.
Uhl, W.
Powiązania:
https://bibliotekanauki.pl/articles/391686.pdf
Data publikacji:
2012
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Odlewnictwa
Tematy:
FAP
staliwo wysokoaluminiowe
Fe-Al
straty aluminium
twardość
udarność
high-aluminium cast steel
aluminium loss
hardness
impact resistance
Opis:
W artykule opisano wytop staliwa na bazie Fe-Al. Poruszono zagadnienia technologiczne realizacji wytopu, zaczynając od symulacji komputerowej, kończąc na obróbce odlewu. Efektem pracy było uzyskanie odlewów pracujących w wysokiej temperaturze. Oprócz praktycznych uwag skupiono się na opisie sposobów minimalizacji strat Al oraz na metodach uzyskania odlewów pozbawionych wad typowych dla tego typu staliwa lub żeliwa. Zwrócono szczególną uwagę na twardość i udarność stopów na bazie Fe-Al.
Melting of cast steel based on Fe-Al system was described. Problems of technological nature related with the melting process performance, starting with computer simulation and in the casting treatment ending, were discussed. The outcome of the study was designing and making of castings for high temperature operation. In addition to practical observations, attention was focussed on the development of methods to reduce to minimum the loss of Al and on the methods to make castings without the defects typical for this type of cast iron or cast steel. Another object of discussion was hardness and impact resistance of alloys based on Fe-Al.
Źródło:
Prace Instytutu Odlewnictwa; 2012, 52, 4; 113-126
1899-2439
Pojawia się w:
Prace Instytutu Odlewnictwa
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Vertical vibrations of composite bridge/track structure/high-speed train systems. Part 2: Physical and mathematical modelling
Autorzy:
Podworna, M.
Klasztorny, M.
Powiązania:
https://bibliotekanauki.pl/articles/200194.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
composite steel-concrete bridge
ballasted track structure
high-speed train
random track irregularities
FE modelling
equations of motion
Opis:
A theory of one-dimensional physical and mathematical modelling of the composite (steel-concrete) bridge/track structure/highspeed train system is developed including viscoelastic suspensions of rail-vehicles with two two-axle bogies each, non-linear Hertz contact stiffness and one-sided contact between wheel sets and rails, the viscoelastic and inertia features of the bridge, the viscoelastic track structure on and beyond the bridge, approach slabs, and random vertical track irregularities. Compared to the state-of-the-art, the physical model developed in the study accurately reproduces dynamic processes in the considered system. Division of the system into the natural subsystems, a method of formulation of the equations of motion partly in implicit form and the finite element method are applied. Vibrations in the vertical plane of symmetry are described by more than nine matrix equations of motion with constant coefficients. Couplings and non-linearity are hidden in the generalized load vectors. The equations of motion are integrated using the implicit Newmark average acceleration method with linear extrapolation of the interactions between the subsystems.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2014, 62, 1; 181-196
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Vertical vibrations of composite bridge/track structure/high-speed train systems. Part 1: Series-of-types of steel-concrete bridges
Autorzy:
Podworna, M.
Klasztorny, M.
Powiązania:
https://bibliotekanauki.pl/articles/202151.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
composite steel-concrete bridge
ballasted track structure
high-speed train
design
FE modelling
simulation
forced resonances
numerical analysis
Opis:
A new series-of-types of single-span simply-supported railway composite (steel-concrete) bridges, with a symmetric platform, has been designed according to the Polish bridge standards. The designed bridges/viaducts are located on the main railways of the classification coefficient k = +2. A ballasted track structure adapted to high operating speeds has also been designed. The ultimate limit states and the limit states corresponding to the bridges undertaken are collected and discussed. The bridges have been designed in accordance with contemporary art engineering, with geometric and material optimization, avoiding overdesign. A new methodology of numerical modelling and simulation of dynamic processes in composite bridge/ballasted track structure/high speed train systems, developed in Part 2 and Part 3, has been applied and implemented in a problem-oriented computer programme. A new approach to predicting forced resonances in those systems is formulated and tested numerically. It has been proved that in the case of typical structural solutions of bridges and ballasted track structures, it is necessary to introduce certain limitations for operating speeds of trains.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2014, 62, 1; 165-179
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Fabrication Method of Fe-TiB2 Nanocomposite Powders on Spark-Plasma Sintering Behavior
Autorzy:
Bae, Sun-Woo
Huynh, Xuan-Khoa
Kim, Ji-Soon
Powiązania:
https://bibliotekanauki.pl/articles/351535.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Fe-TiB2 composite
ex-situ
in-situ
iron boride
titanium hydride
high-energy ball-milling
spark plasma sintering
densification behavior
Opis:
In this study, Fe-40wt% TiB2 nanocomposite powders were fabricated by two different methods: (1) conventional powder metallurgical process by simple high-energy ball-milling of Fe and TiB2 elemental powders (ex-situ method) and (2) high-energy ball-milling of the powder mixture of (FeB+TiH2 ) followed by reaction synthesis at high temperature (in-situ method). The ex-situ powder was prepared by planetary ball-milling at 700 rpm for 2 h under an Ar-gas atmosphere. The in-situ powder was prepared under the same milling condition and heat-treated at 900°C for 2 h under flowing argon gas in a tube furnace to form TiB2 particulates through a reaction between FeB and Ti. Both Fe-TiB2 composite powder compacts were sintered by a spark-plasma sintering (SPS) process. Sintering was performed at 1150°C for the ex-situ powder compact and at 1080°C for the in-situ powder for 10 minutes under 50 MPa of sintering pressure and 0.1 Pa vacuum for both processes. The heating rate was 50°/min to reach the sintering temperature. Results from analysis of shrinkage and microstructural observation showed that the in-situ composite powder compacts had a homogeneous and fine microstructure compared to the ex-situ preparation, even though the sintered densities were almost the same (99.6 and 99.8% relative density, respectively).
Źródło:
Archives of Metallurgy and Materials; 2020, 65, 3; 1023-1028
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 17

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