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Wyświetlanie 1-15 z 83
Tytuł:
Preliminary studies of the influence of starch irradiation on physicochemical properties of films prepared using starch and starch-surfactant systems
Autorzy:
Cieśla, K. A.
Nowicki, A.
Buczkowski, M. J.
Powiązania:
https://bibliotekanauki.pl/articles/148406.pdf
Data publikacji:
2010
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
starch films
starch-surfactants films
gamma irradiation
mechanical properties
barrier properties
hydrophobic
Opis:
The influence was studied of potato and wheat starch irradiation on physicochemical properties of films, prepared using either starch alone or a composition of potato starch with three surfactants: sodium laurate, sodium palmitate and cetyl-trimethyl-ammonium bromide (CTAB). The surfactants were introduced at a level of 0.038 division sign 0.075 g per 1 g of starch. This corresponds to 0.136–0.222 mmol/g, depending on the surfactant type and its amount used. Irradiations were carried out using 60Co radiation with doses of 5, 10, 20 and 30 kGy. Films were prepared with addition of glycerol (0, 20 or 30% in terms of starch mass) by means of casting from the gelatinized starch or starch-surfactant solutions. With the purpose to characterize the films, mechanical tests (using an Instron instrument) and the wetting angle measurements were performed. The effect was determined of the storage and conditioning in an atmosphere characterized by the various moisture content on the properties of films with various compositions. The results show the radiation-induced improvement of hydrophobic properties of the films prepared using potato and wheat starch, and the selected potato starch-surfactant compositions. Improvement of strength and flexibility was obtained in the case of potato starch films, while in the case of wheat starch films the increase of strength was accompanied by a decrease in flexibility. Improvement of the functional properties of potato starch films corresponds to the improvement of their structural properties, found by scanning electron microscopy (SEM). The possibilities of modification of the films properties by modification of composition and radiation treatment were discussed.
Źródło:
Nukleonika; 2010, 55, 2; 233-242
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of arc stud welding parameters on the microstructure and mechanical properties of AA6061 and AA5086 aluminium alloys
Autorzy:
Razzaq, M. K. A.
Abood, A. N.
Powiązania:
https://bibliotekanauki.pl/articles/2055760.pdf
Data publikacji:
2021
Wydawca:
Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
Tematy:
arc stud welding
aluminium alloys
solidification mode
fusion zone
mechanical properties
spawanie łukowe
stopy aluminium
model krzepnięcia
strefa przetopienia
właściwości mechaniczne
Opis:
Purpose: This paper aims to investigate the effect of arc stud welding (ASW) process parameters on the microstructure and mechanical properties of AA6061-T6 and AA5086-H116 joint. Design/methodology/approach: ASW process was done with argon as a shielding gas. Optical microscope (OM), scanning electron microscope (SEM), and X-Ray Diffraction (XRD) were employed to investigate the influence of welding current, welding time, and gas flow-rate on the microstructure of the fusion zone (FZ). Torque strength and Microhardness tests were used to evaluate the mechanical properties of the welded joints. Findings: OM and SEM showed a cellular dendritic structure with equiaxed zone and columnar dendritic are forming at welding zone and weld interface. XRD analysis showed the precipitation of Mg2Si and Al3Mg2 in the similar and dissimilar joints. Similar ASW of AA6061-T6/AA6061-T6 recorded 19 N.m torque strength, while dissimilar welding of AA6061-T6/AA5086-H116 registered 23 N.m. With increasing heat input, grains in Fusion Zone (FZ) and Heat Affected Zone (HAZ) coarsen and the hardness in both zones decreased. The hardness of similar weldments indicated a remarkable softening of FZ, while lower hardness values were registered in HAZ of dissimilar weldments. Softening of both weldments is due to the dissolution of the strengthening precipitates. Hot cracks exist with similar weldments, while no cracks evidence with dissimilar weldments. Research limitations/implications: The main challenge in this work was how to minimize porosity level and how to avoid hot crack in the FZ. Practical implications: The application of ASW with ceramic ferrule has an important role in different production areas such as; automobile industry, aircraft applications, and appliances industry. Originality/value: Study the effect of welding current, welding time, and gas flow-rate of ASW process on microstructure and mechanical properties of AA6061-T6 and AA5086-H116 joint.
Źródło:
Journal of Achievements in Materials and Manufacturing Engineering; 2021, 108, 1; 24--34
1734-8412
Pojawia się w:
Journal of Achievements in Materials and Manufacturing Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The influence of ionizing radiation on the properties of starch-PVA films
Autorzy:
Abramowska, A.
Cieśla, K. A.
Buczkowski, M. J.
Nowicki, A.
Głuszewski, W.
Powiązania:
https://bibliotekanauki.pl/articles/147450.pdf
Data publikacji:
2015
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
starch
poly(vinyl alcohol)
films
ionizing radiation
mechanical properties
physicochemical properties
Opis:
The cornstarch: poly(vinyl alcohol) (PVA) films characterized by the alternating ratio of starch:PVA (100:0, 80:20, 60:40, 40:60, 20:80, and 0:100) and containing 30% of glycerol were prepared by solution casting. The films were irradiated with an absorbed dose of 25 kGy with gamma rays in a vacuum and with fast electrons in the air. The films characterized by a high content of starch appeared stiff, while the films characterized by a high content of PVA were highly flexible. The tensile strength and flexibility, as well as swelling and hydrophilicity, increased with the increase in the PVA content in the films. However, the tensile strength and wetting angle values achieved a minimum at an intermediate composition. It was found that irradiation enables to reduce hydrophilicity of the films accompanied by a decrease in their flexibility. No general conclusion concerning the effect of irradiation on tensile strength and swelling behavior can be derived. An increase in the homogeneity of the films and an increase in the compatibility of their components was found by scanning electron microscopy (SEM). Strong interactions of the starch and the PVA components were discovered by diffuse reflectance spectroscopy. Degradation was found to be the prevailing process occurring in the films under the infl uence of irradiation. The possible accompanying crosslinking is discussed in terms of the gel content in the samples. Creation of various oxidation products in the films characterized by the modified composition was observed under the influence of irradiation carried out in the air. Basing on the obtained results it can be supposed that the selected starch-PVA compositions might appear useful as packagings of the products predicted for radiation decontamination.
Źródło:
Nukleonika; 2015, 60, No. 3, part 2; 669-677
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Environmental factors influence milling and physical properties and flour size distribution of organic spelt wheat
Autorzy:
Warechowska, M.
Warechowski, J.
Skibniewska, K. A.
Siemianowska, E.
Tyburski, J.
Aljewicz, M. A.
Powiązania:
https://bibliotekanauki.pl/articles/298457.pdf
Data publikacji:
2016
Wydawca:
Uniwersytet Warmińsko-Mazurski w Olsztynie
Tematy:
organic spelt
physical properties
mechanical properties
milling
particle size distribution
PSD
Opis:
Spelt grain harvested at four organic farms in Poland were assessed for physical and milling properties and flour size distribution. The spelt grain was diversified in relation to the majority of tested milling quality parameters. The environmental conditions had a significant impact on thousand kernel weight, vitreousness, PSI, kernel ash content, specific energy of milling and the particle size distribution of flour. The values of specific energy of milling, coefficient of grinding efficiency, rupture force and rupture energy in the spelt from the organic farms were significantly lower than common wheat. The highest spelt flour yield was obtained of kernels cultivated on ecological farm with semi-coherent and very dry soil was similar to that of common wheat; the milling yield of the spelt originating from other farms was by 9.5% to 12.7% less than from the wheat one. The greatest differences in PSD between the tested flours were detected for the values over 40 μm. The content of this fraction was determined in the range of app. 1% to almost 4.5%; the flour from common wheat contained app. 2.8% of this fraction.
Źródło:
Technical Sciences / University of Warmia and Mazury in Olsztyn; 2016, 19(4); 387-399
1505-4675
2083-4527
Pojawia się w:
Technical Sciences / University of Warmia and Mazury in Olsztyn
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hybrydowe biokompozyty polimerowe wzmocnione mikrowłóknami z łusek zbożowych i mączką drzewną
Hybrid biocomposites reinforced with fibres from grain by-products and softwood flour
Autorzy:
Urbaniak, M.
Błędzki, A. K.
Powiązania:
https://bibliotekanauki.pl/articles/278732.pdf
Data publikacji:
2017
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Inżynierii Materiałów Polimerowych i Barwników
Tematy:
kompozyty polimerowe
biokompozyty hybrydowe
włókna naturalne
biożywica epoksydowa
właściwości mechaniczne
polymer composities
hybrid biocomposities
natural fibres
bio-based epoxy resin
mechanical properties
Opis:
Warunkiem zrównoważonego rozwoju gospodarczego jest ochrona środowiska naturalnego, zatem konieczne jest stosowanie eko-przyjaznych technologii i nowoczesnych materiałów, takich jak biokompozyty polimerowe zarówno termoplastyczne, jak i duroplastyczne wzmacniane włóknami naturalnymi. Biokompozyty te znajdują coraz szersze zastosowania inżynierskie. W artykule przedstawiono wyniki badań hybrydowych biokompozytów polimerowych na osnowie biożywicy epoksydowej wzmocnionych mikrowłóknami pozyskanymi z produktów ubocznych pochodzących z przemysłu rolno-spożywczego oraz z przemysłowej mączki drzewnej. Zastosowano mikrowłókna z łusek zbożowych - owsa i jęczmienia, które są dotychczas niezagospodarowanym racjonalnie odpadem przemysłu zbożowego, powstającymi podczas mielenia zbóż. Opracowane hybrydowe materiały kompozytowe wykazały wyższe właściwości wytrzymałościowe i użytkowe w stosunku do klasycznego kompozytu WPC i mogą stanowić jego przyjazną środowisku alternatywę.
Sustainable progress of economy is conditioned under environmental requirements then more extensive applications of eco-friendly technology and novel materials like polymer composites, both thermoplastic and thermosetting ones reinforced with natural fibres are needful. Such biocomposites are applicable widely in material engineering now. This article comprises the results of research on hybrid polymer biocomposites with bio-based epoxy resin reinforced with microfibres derived from grain by-products of agricultural industry or arised from industrial grade wood flour. Microfibres from grain husks of oat and barley as unutilized waste of milling industry were used. Manufactured hybrid composite materials showed improved mechanical and profitable properties compared to standard WPC composites and owing to that can be eco-friendly alternative for the latter.
Źródło:
Przetwórstwo Tworzyw; 2017, T. 23, Nr 5 (179), 5 (179); 458-465
1429-0472
Pojawia się w:
Przetwórstwo Tworzyw
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Polipropylen wzmacniany mikrowłóknami drzewnymi jako materiał kompozytowy do wtryskiwania cienkościennego
Wood microfibres reinforced polypropylene as a composite material for thin wall injection moulding
Autorzy:
Meljon, A.
Błędzki, A. K.
Stańkowska-Walczak, D.
Powiązania:
https://bibliotekanauki.pl/articles/279081.pdf
Data publikacji:
2014
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Inżynierii Materiałów Polimerowych i Barwników
Tematy:
wtryskiwanie
wtryskiwanie cienkościenne
materiał kompozytowy
biokompozyt
polipropylen
PP
mikrowłókna naturalne
mikrowłókna drzewne
mączka drzewna
wytłaczarka dwuślimakowa
właściwości przetwórcze
właściwości mechaniczne
injection moulding
thin wall injection moulding
composite material
biocomposite
polypropylene
natural microfibres
wood microfibres
wood flour
twin-screw extruder
processing properties
mechanical properties
Opis:
W artykule przedstawiono wyniki badań eksperymentalnych polipropylenu wzmacnianego mączką drzewną jako biokompozytowego materiału na wtryskiwane wyroby cienkościenne. Biokompozyty wytwarzane były przez kompaundowanie na standardowej wytłaczarce dwuślimakowej w skali półtechnicznej, a następnie wtryskiwane na wtryskarce skali przemysłowej celem jak najbliższego odtworzenia warunków przemysłowych wytwarzania wyrobów cienkościennych. Oceniono właściwości przetwórcze i mechaniczne kompozytów o różnej zawartości mikrowłókien drzewnych (od 15 do 30%wag). Opracowane materiały wykazały podwyższone właściwości mechaniczne w porównaniu do niemodyfikowanego polipropylenu przy zachowaniu jednoczesnego dobrego płynięcia podczas przetwórstwa. Tym samym mogą stanowić one przyjazną środowisku alternatywę dla wyrobów cienkościennych produkowanych w całości z materiałów syntetycznych.
The present paper introduces the results of experimental research on polypropylene reinforced with wood flour as a biocomposite material for thin-walled injection moulded parts. Biocomposites were manufactured using half-technical scale twin-screw extruder and afterwards injection moulded with industrial-scale injection moulding machine to obtain processing conditions similar to industrial manufacturing of thin-walled products. Processing and mechanical properties of composites with various content of wood microfibres (15 to 30 wt%) were examined. The investigated materials showed improved mechanical characteristics in comparison to unmodified polypropylene while maintaining good flowability and therefore they can be an environmentally friendly alternative to synthetic materials commonly applied for manufacturing thin-walled products.
Źródło:
Przetwórstwo Tworzyw; 2014, [R.] 20, nr 6 (162), 6 (162); 551-554
1429-0472
Pojawia się w:
Przetwórstwo Tworzyw
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Preconditiong and Inoculation of Low Sulphur Grey Iron
Autorzy:
Hossain, Md Sojib S.
Bazlur B. Rashid, A. K. M.
Powiązania:
https://bibliotekanauki.pl/articles/380548.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
grey iron
metallography
mechanical properties
cementite
preconditioner
inoculant
żeliwo szare
metalografia
właściwości mechaniczne
cementyt
Opis:
For quality grey cast iron production, the challenging issues are to avoid cementite structure and obtain the desired graphite morphology with proper matrix as well as hardness. The objective of the present research is to find out the right combination of preconditioner and inoculant that may help to overcome the challenges. In this work, sulphur content is kept low (0.01%). Two preconditioners namely metallurgical SiC and zirconium bearing FeSi with two types of inoculant are individually used to make four combinations of sample and for each case metal is poured into the green sand mould. Finally Brinell hardness and graphite morphology is observed in the thickest and thinnest portions of the castings. Metallurgical SiC with barium bearing inoculant gives better graphite morphology and hardness than strontium bearing inoculant, on the other hand zirconium bearing FeSi gives more satisfying result than SiC with every type of inoculant. Among all of the combinations Zr bearing preconditioner with Ba bearing inoculant gives good graphite morphology with best mechanical properties in both thickest and thinnest portions of the casting.
Źródło:
Archives of Foundry Engineering; 2020, 20, 1; 61-66
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Grain Boundary Wetting and Material Performance in an Industrial EZ33A Mg Cast Alloy
Autorzy:
Straumal, A. B.
Tsoy, K. V.
Mazilkin, I. A..
Nekrasov, A. N.
Bryła, K.
Powiązania:
https://bibliotekanauki.pl/articles/352347.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
grain boundary
wetting
cast alloy
Mg
mechanical properties
Opis:
The grain boundary wetting phase transition in an industrial EZ33A cast alloy is studied. 12% of the grain boundaries are completely wetted at the temperature slightly higher than the eutectic transformation temperature (530°C). The fraction of wetted grain boundaries increases with temperature, reaches a maximum of 85% at 570°C, and does not change further until the alloy melts. In the as-cast state, the alloy has low ductile properties at the ambient temperature. The microstructure in the as-cast state corresponds to the wetting state at about 560°C, which indicates that the cooling rate in casting is almost equal to that in quenching. The volume and the surface fraction of the second phase and the hardness measured at the least wetted state of samples point toits good machinability. The wetting data are used to suggest a sequence of heat treatment and machining for processing EZ33A alloy parts.
Źródło:
Archives of Metallurgy and Materials; 2019, 64, 3; 869-873
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Study on Creep Behavior of Composite Solid Propellants Using the Kelvin-Voigt Model
Autorzy:
Bihari, B. K.
Rao, N. P. N.
Gupta, M.
Murthy, K. P. S.
Powiązania:
https://bibliotekanauki.pl/articles/358395.pdf
Data publikacji:
2017
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
mechanical properties
viscoelasticity
propellant
creep
DMA
Opis:
A Kelvin-Voigt model consisting of a spring and a dashpot in parallel was applied for the viscoelastic characterization of solid rocket propellants. Suitable values of spring constants and damping coefficients were employed by a least squares fit of the errors to generate creep curves using a Dynamic Mechanical Analyzer (DMA) for composite solid propellants. Three different composite propellant formulations based on HTPB/AP/Al having burning rates of 5 mm/s, 15 mm/s and 20 mm/s were tested under different stress levels varying from 0.1 MPa to 3 MPa and at different temperatures varying from 35 °C to 85 °C. Creep behavior with recovery was studied and analyzed to evaluate the viscoelastic properties. The change in spring constants, representing elastic deformation, was very small compared to the damping coefficients for the propellants studied. For a typical propellant formulation, when the stress level was increased, the spring and damping coefficient both increased significantly whereas for an increase in temperature, they remained nearly constant. However, the ratio E/η was observed to be constant and independent of stress level. It was also observed that the variation of E and η varied linearly with increase in stress whereas their ratio showed a logarithmic variation. A mathematical correlation was developed to evaluate the viscoelastic properties during creep of composite propellants.
Źródło:
Central European Journal of Energetic Materials; 2017, 14, 3; 742-756
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Strukturalne uwarunkowania właściwości mechanicznych kompozytów A359 + Al2O3 po wielokrotnym przetopie
Structural determinants of the mechanical properties of A359 + Al2O3 composites after multiple remelting
Autorzy:
Pietrzak, K.
Klasik, A.
Makowska, K.
Sobczak, J. J.
Wojciechowski, A.
Rudnik, D.
Sienicki, E.
Powiązania:
https://bibliotekanauki.pl/articles/391797.pdf
Data publikacji:
2016
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Odlewnictwa
Tematy:
kompozyty
recykling
właściwości mechaniczne
wielokrotny przetop
composites
recycling
mechanical properties
multiple remelting
Opis:
W artykule przedstawiono możliwości zastosowania bezpośredniego wielokrotnego przetopu, jako łatwej oraz uzasadnionej merytorycznie i ekonomicznie metody recyklingu kompozytu o osnowie stopu A359 zbrojonego cząsteczkami Al2O3. Bezpośredni przetop przeprowadzono w połączeniu z dwiema metodami odlewania, stosując odlewanie grawitacyjne oraz prasowanie w stanie ciekłym (squeeze casting). Skuteczność proponowanej metody zweryfikowano w oparciu o wybrane badania materiałowe. Wykazano, że w wyniku odlewania grawitacyjnego parametry mechaniczne, wynikające ze statycznej próby rozciągania, do piątego przetopu pogarszają się o 15%, co wynika z pojawiającej się przy tej technice odlewania porowatości gazowo-skurczowej. Wykazano również, że w przypadku zastosowania metody prasowania w stanie ciekłym parametry mechaniczne oraz parametry geometryczne mikrostruktury pozostają aż do dziesiątego przetopu praktycznie na takim samym poziomie jak w stanie wyjściowym. Uzyskane wyniki potwierdziły możliwość stosowania bezpośredniego przetopu, jako alternatywnej metody dla innych kosztownych metod recyklingu.
The article discusses the possibilities of applying direct multiple remelting as an easy as well as substantially and economically justified method of recycling composites with an A359 alloy matrix reinforced with Al2O3 particles. Direct remelting was performed in connection with two casting procedures, i.e. with the use of gravity casting and squeeze casting. The effectiveness of the proposed methods was verified based on the selected material tests. It was demonstrated that, as a result of gravity casting, the mechanical parameters resulting from the static tensile test, up to the fifth remelting, worsen by 15%, which is a consequence of the gas-contraction porosity occurring in the case of this casting technique. It was also proved that, in the case of the use of squeeze casting, the mechanical and geometrical parameters of the microstructure, up to the tenth remelting, remain practically at the same level as in the initial state. The obtained results confirmed the possibility of using direct remelting as an alternative method for other costly recycling methods.
Źródło:
Prace Instytutu Odlewnictwa; 2016, 56, 2; 87-112
1899-2439
Pojawia się w:
Prace Instytutu Odlewnictwa
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hydrophilic Modified clay Nanocomposites: Effect of clay on Thermal and Vibrational Properties
Autorzy:
Kishore, A.
Venkatesh, D. B.
Kumar, M. A.
Ramesh, A.
Murthy, K. N.
Karthikeyan, N.
Powiązania:
https://bibliotekanauki.pl/articles/411937.pdf
Data publikacji:
2014
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Hydrophilic nanoclay
Epoxy Nanocomposites
mechanical properties
Opis:
Epoxy (LY-556/HY-951) system filled with modified clay (MC) was synthesized by using mechanical shear mixing with the addition of hardener as tri-ethylene-tetra-amine (TETA). The effect of the fumed silica can be negated by the application of a shear force (e.g. mixing, brushing, spraying etc), allowing the liquid to flow, level out and permit the escape of entrapped air. The reinforcement effects of MC in the epoxy polymer on thermal, mechanical and vibration properties were studied. Curing study shows that the addition MC does not show any effect in the curing behavior of epoxy polymer. Thermogravimetry analysis (TGA) shows enhanced thermal stability for epoxy with MC fillers. The epoxy with MC fillers shows considerable improvement on tensile and impact properties over pure epoxy polymer. SEM studies shows that addition of clay significantly turns the epoxy system from brittle to ductile nature was played instrumental in scaling performance. The improvement in tensile and impact properties of nanocomposites is supported with the fracture surface studies. Epoxy with MC fillers shows enhanced vibration characteristics than that of the pure epoxy polymer. FTIR studies indicated the formation of C-H bonds on the surface of the nanocomposites.
Źródło:
International Letters of Chemistry, Physics and Astronomy; 2014, 8; 73-86
2299-3843
Pojawia się w:
International Letters of Chemistry, Physics and Astronomy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Microstructure and Fatigue Life of the A359 Alloy Reinforced with Al2O3 after Multiple Remelting
Autorzy:
Pietrzak, K.
Klasik, A.
Maj, M.
Sobczak, J.
Wojciechowski, A.
Powiązania:
https://bibliotekanauki.pl/articles/380378.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
A359 alloy
composite microstructure
mechanical properties
multiple remelting
stop A359
mikrostruktura kompozytu
właściwości mechaniczne
przetapianie wielokrotne
Opis:
The multiple direct remelting of composites based on the A359 alloy reinforced with 20% of Al2O3 particles was performed. The results of both gravity casting and squeeze casting were examined in terms of the obtained microstructure and mechanical characteristics. In microstructure examinations, the combinatorial method based on phase quanta theory was used. In mechanical tests, the modified low cycle fatigue method (MLCF) was applied. The effects obtained after both gravity casting and squeeze casting were compared. It was noted that both characteristics were gradually deteriorating up to the tenth remelting. The main cause was the occurrence of shrinkage porosity after the gravity casting. Much better results were obtained applying the squeeze casting process. The results of microstructure examinations and fatigue tests enabled drawing the conclusion that the A359 alloy reinforced with Al2O3 particles can confer a much better fatigue life behavior to the resulting composite than the A359 alloy without the reinforcement. At the same time, comparing these results with the results of the previous own research carried out on the composites based also on the A359 alloy but reinforced in the whole volume with SiC particles, it has been concluded that both types of the composites can be subjected to multiple remelting without any significant deterioration of the structural and mechanical characteristics. The concepts and advantages of using the combinatorial and MLCF methods in materials research were also presented.
Źródło:
Archives of Foundry Engineering; 2018, 18, 2; 39-44
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ageing Behaviour of HTPB Based Rocket Propellant Formulations
Autorzy:
Cerri, S.
Bohn, M. A.
Menke, K.
Galfetti, L.
Powiązania:
https://bibliotekanauki.pl/articles/358902.pdf
Data publikacji:
2009
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
solid rocket propellant
HTPB
nanoAl
ageing
mechanical properties
Opis:
The ageing of HTPB propellant formulations containing nanoAl is investigated. During natural ageing the material undergoes a series of slow physico-chemical degradation reactions. By using accelerated ageing conditions it is possible to simulate the material behaviour at different time-temperature conditions especially focused on the in-service conditions. The mechanical and ageing behaviour of aluminised solid rocket propellants were investigated in terms of uniaxial tensile strength, DMA measurements, impact and friction sensitivity tests, SEM analyses.
Źródło:
Central European Journal of Energetic Materials; 2009, 6, 2; 149-165
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Sterilization and Exposure to the Ringers Solution on Mechanical and Physicochemical Properties of Nitrocarburized 316 LVM Steel
Autorzy:
Kajzer, A.
Rabij, K.
Basiaga, M.
Nowińska, K.
Kaczmarek, M.
Borowski, T.
Wierzchoń, T.
Powiązania:
https://bibliotekanauki.pl/articles/356523.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
AISI 316LVM steel
nitrocarburizing process
mechanical properties
physico-chemical properties
Opis:
Studies on biocompatibility of AISI 316LVM steel indicate the need to eliminate the nickel from the surface and replace it with other elements of improved biocompatibility. Therefore, in the presented work selected physicochemical and mechanical properties of the diffusive nitrocarburized layer formed by plasma potential by means of an active screen made of the Fe-Cr-Ni were studied. In the paper we present results of microstructure and phase composition of the layers, roughness, and surface wettability, potentiodynamic pitting corrosion resistance, penetration of ions into the solution as well as mechanical properties. The studies were conducted for the samples of both mechanically polished and nitrocarburized surfaces, after sterilization, and exposure to the Ringer’s solution. Deposition of the nitrocarburized layer increased the contact angle, surface roughness, surface hardness, and corrosion resistance with respect to the polished surfaces. The nitrocarburized layer is a barrier against the ions release into the solution and sterilization and exposure to Ringer solution. The obtained results showed beneficial increase of both mechanical and electrochemical properties of the deposited layer, and thus the applicability of the proposed method of surface treatment of the 316 LVM steel for short-term implants after sterylization.
Źródło:
Archives of Metallurgy and Materials; 2018, 63, 3; 1257-1266
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparative Studies of Microstructure and Fatigue Life of Selected Lead-free Alloys
Autorzy:
Pietrzak, K.
Klasik, A.
Maj, M.
Sobczak, N.
Wojciechowski, A.
Powiązania:
https://bibliotekanauki.pl/articles/379514.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
lead free alloys
microstructure
mechanical properties
stopy bezołowiowe
mikrostruktura
właściwości mechaniczne
Opis:
Lead-free alloys containing various amounts of zinc (4.5%, 9%, 13%) and constant copper addition (1%) were discussed. The results of microstructure examinations carried out by light microscopy (qualitative and quantitative) and by SEM were presented. In the light microscopy, a combinatorial method was used for the quantitative evaluation of microstructure. In general, this method is based on the phase quanta theory according to which every microstructure can be treated as an arrangement of phases/structural components in the matrix material. Based on this method, selected geometrical parameters of the alloy microstructure were determined. SEM examinations were based on chemical analyses carried out in microregions by EDS technique. The aim of the analyses was to identify the intermetallic phases/compounds occurring in the examined alloys. In fatigue testing, a modified low cycle fatigue test method (MLCF) was used. Its undeniable advantage is the fact that each time, using one sample only, several mechanical parameters can be estimated. As a result of structure examinations, the effect of alloying elements on the formation of intermetallic phases and compounds identified in the examined lead-free alloys was determined. In turn, the results of mechanical tests showed the effect of intermetallic phases identified in the examined alloys on their fatigue life. Some concepts and advantages of the use of the combinatorial and MLCF methods in materials research were also presented.
Źródło:
Archives of Foundry Engineering; 2017, 17, 3; 111-116
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 83

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