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    Wyświetlanie 1-15 z 15
    Tytuł:
    Evaluation of Impact Strength and Microstructure as Quality Criteria for Selected Materials
    Autorzy:
    Maj, M.
    Pietrzak, K.
    Lasota, P.
    Powiązania:
    https://bibliotekanauki.pl/articles/379533.pdf
    Data publikacji:
    2014
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    steel
    cast iron
    hardness
    microstructure
    impact strength
    stal
    żeliwo
    twardość
    mikrostruktura
    wytrzymałość
    Opis:
    The article presents the results of analysis of the chemical composition, hardness, microstructure and toughness of selected structural materials. The focus is on the results of impact tests carried out on the 40H steel quenched and tempered at three different temperatures, on grey cast iron used in industrial practice (cast material for brake drums) and on ADI, all of them being considered representatives of the group of materials commonly used in the production of structural elements and finished products, including items for use in the automotive industry. The impact tests were performed at a reduced temperature (-20°C), at room temperature (20°C) and at elevated temperature (150°C), comparing the results obtained with the microstructure of materials tested. It has been shown that in the case of steel, the smallest changes in microstructure cause changes in toughness, while the effect of tempering temperature is in this case of secondary importance. It was also proved that under the conditions of ambient temperature and reduced temperature, better results were obtained for ADI. At elevated temperature, better results were obtained for grey iron castings.
    Źródło:
    Archives of Foundry Engineering; 2014, 14, 1 spec.; 199-204
    1897-3310
    2299-2944
    Pojawia się w:
    Archives of Foundry Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Fatigue Life and Microstructure after Multiple Remelting of A359 Matrix Composites Reinforced with SiC Particles
    Autorzy:
    Klasik, A.
    Maj, M.
    Pietrzak, K.
    Wojciechowski, A.
    Sobczak, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/352210.pdf
    Data publikacji:
    2016
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    alloy
    composite
    microstructure
    properties
    recycling
    Opis:
    The article presents the results of fatigue life tests and microstructure examinations of A359 alloy matrix composites (F3S.10S and F3S.30S) containing 10 and 30wt% of SiC particles, subjected to multiple remelting by conventional gravity casting. Mechanical characteristics were determined in a modified low cycle fatigue (MLCF) test, enabling rapid estimation of fatigue life and other mechanical parameters in practice of any material. Qualitative and quantitative metallographic examinations were also carried out. The quantitative evaluation of microstructure was performed by computer image analysis. A set of geometrical parameters of the reinforcing particles, pores and eutectic precipitates present in the metal matrix was determined. The relationships between the mechanical parameters, structural characteristics and the number of remelting operations were presented. It was found that up to the fourth remelting, the mechanical characteristics, including fatigue life, are slightly deteriorated but decrease gradually in the subsequent operations of remelting. The observed effect is mainly due to the shrinkage porosity occurring as a result of gravity casting. To eliminate this defect, the use of squeeze casting process was recommended. It has also been shown that multiple remelting can be an easy and economically well-founded alternative to other more expensive recycling methods.
    Źródło:
    Archives of Metallurgy and Materials; 2016, 61, 4; 2123-2128
    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
    Tytuł:
    Microstructure and Fatigue Life of the Binary Lead-free Alloys with High Zn Content
    Autorzy:
    Pietrzak, K.
    Klasik, A.
    Maj, M.
    Sobczak, N.
    Powiązania:
    https://bibliotekanauki.pl/articles/382479.pdf
    Data publikacji:
    2018
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    lead free alloy
    alloy microstructure
    mechanical properties
    stop bezołowiowy
    mikrostruktura stopu
    właściwości mechaniczne
    Opis:
    The results of studies presented in this article are an example of the research activity of the authors related to lead-free alloys. The studies covered binary SnZn90 and SnZn95 lead-free alloys, including their microstructure and complex mechanical characteristics. The microstructure was examined by both light microscopy (LM) and scanning electron microscopy (SEM). The identification of alloy chemical composition in micro-areas was performed by SEM/EDS method. As regards light microscopy, the assessment was of both qualitative and quantitative character. The determination of the geometrical parameters of microstructure was based on an original combinatorial method using phase quantum theory. Comprehensive characterization of mechanical behavior with a focus on fatigue life of alloys was performed by means of the original modified low cycle fatigue method (MLCF) adapted to the actually available test machine. The article discusses the fatigue life of binary SnZn90 and SnZn95 alloys in terms of their microstructure. Additionally, the benefits resulting from the use of the combinatorial method in microstructure examinations and MLCF test in the quick estimation of several mechanical parameters have been underlined.
    Źródło:
    Archives of Foundry Engineering; 2018, 18, 4; 65-70
    1897-3310
    2299-2944
    Pojawia się w:
    Archives of Foundry Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Microstructure and Mechanical Characteristics of the Ternary SnZnAl Lead-Free Alloy
    Autorzy:
    Pietrzak, K.
    Klasik, A.
    Maj, M.
    Sobczak, N.
    Powiązania:
    https://bibliotekanauki.pl/articles/380398.pdf
    Data publikacji:
    2018
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    lead free alloy
    microstructure
    mechanical properties
    scanning electron microscopy
    stop bezołowiowy
    mikrostruktura
    właściwości mechaniczne
    mikroskop skaningowy
    Opis:
    The paper describes the studies of ternary SnZn9Al1.5 lead-free alloy from the viewpoint of its mechanical behavior as well as microstructure examined by the light and scanning electron microscopy. The authors focused their attention specifically on the fatigue parameters determined by the original modified low-cycle fatigue method (MLCF), which in a quick and economically justified way allows determination of a number of mechanical parameters based on the measurement data coming from one test sample only. The effect of the addition of 1.5% Al to the binary eutectic SnZn9 alloy on its microstructure and the obtained level of mechanical parameters was analyzed. The phases and intermetallic compounds occurring in the alloy were identified based on the chemical analysis carried out in micro-areas by the SEM/EDS technique. It was shown that the addition of 1.5% Al to the binary eutectic SnZn9 alloy resulted in a more favorable microstructure and consequently had a positive effect on the mechanical parameters of the alloy. Based on the conducted research, it was recommended to use a combinatorial method based on the phase quanta theory to quickly evaluate the microstructure and the original MLCF method to determine a number of mechanical parameters.
    Źródło:
    Archives of Foundry Engineering; 2018, 18, 3; 31-36
    1897-3310
    2299-2944
    Pojawia się w:
    Archives of Foundry Engineering
    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:
    Microstructure and properties of hot-pressed molybdenum-alumina composites
    Spiekane kompozyty molibden-Al2O3 - struktura i właściwości
    Autorzy:
    Chmielewski, M.
    Dutkiewicz, J.
    Kaliński, D.
    Lityńska-Dobrzyńska, L.
    Pietrzak, K.
    Strojny-Nędza, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/354228.pdf
    Data publikacji:
    2012
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    materiały ceramiczne
    kompozyty ceramiczno-metalowe
    technika spiekania
    ceramic-metal composites
    hot pressing
    microstructure
    interface
    mechanical properties
    Opis:
    Brittleness is the main technical limitation on a wide use of advanced ceramic materials. To overcome this problem, ceramic-metal composites are commonly applied. A principal advantage of ceramic-metal composite materials is their higher resistance to brittle fracture. An increase of fracture toughness depends on the type, amount, size and shape of a metallic component. The metallic phase can additionally modify physical, mechanical and thermal properties of materials. The results of experiments concerning a manufacturing process of Mo-Al2O3 composite materials obtained by the hot pressing method were presented. Two powder mixtures with different volume fraction of aluminium oxide were prepared in a planetary ball mill. The hot pressing process allowed to obtain well-densified metal matrix composites (˜99% of a theoretical density). Microstructural observations of sinters were conducted using scanning electron microscopy, energy-dispersive X-ray spectroscopy, and transmission electron microscopy. Very stable bonding between metal and ceramic grains was observed. Complex investigations of the physical and mechanical properties of obtained molybdenum-alumina composite materials seem to be very promising from an application point of view.
    Główna przyczyną ograniczenia stosowalności zaawansowanych materiałów ceramicznych jest ich kruchość. W celu pokonania tego problemu powszechnie stosuje sie kompozyty ceramiczno-metalowe, których zaletą jest wyższa odporność na kruche pękanie w porównaniu z materiałami ceramicznymi. Zależy ona od wielu czynników m.in. rodzaju, ilości, wielkości oraz kształtu zastosowanego metalu. Ostatecznym zmianom ulegają równiez inne właściwości tj. fizyczne, mechaniczne, termiczne. W pracy przedstawiono wyniki technologicznych prób otrzymywania materiałów kompozytowych Mo-Al2O3 przy wykorzystaniu techniki spiekania pod ciśnieniem. Mieszaniny proszków o różnych udziałach objętosciowych fazy ceramicznej przygotowano w planetarnym młynku kulowym. Ostateczny proces zageszczania pozwolił uzyskac materiały o wysokiej gestości względnej (powyżej 99% gęstości teoretycznej). Analizowano mikrostrukturę spieków z wykorzystaniem skaningowej i transmisyjnej mikroskopii elektronowej. Stwierdzono występowanie bardzo dobrego połączenia fazy ceramicznej z osnową metalową. Przeprowadzono szeroką analizą właściwosci fizycznych i mechanicznych uzyskanych kompozytów, co powinno pozwolić na rozszerzenie możliwości aplikacyjnych opracowanych tworzyw.
    Źródło:
    Archives of Metallurgy and Materials; 2012, 57, 3; 686-693
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Processing, Microstructure and Properties of Different Method Obtained Cu-Al2O3 Composites
    Wytwarzanie, mikrostruktura i waściwości kompozytów Cu-Al2O3 otrzymywanych różnymi technikami
    Autorzy:
    Strojny-Nędza, A.
    Pietrzak, K.
    Powiązania:
    https://bibliotekanauki.pl/articles/353859.pdf
    Data publikacji:
    2014
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    ceramic-metal composites
    hot pressing
    tape casting
    microstructure
    thermal properties
    kompozyty ceramiczno-metalowe
    prasowanie na gorąco
    odlewanie taśmy
    mikrotekstura
    właściwości termiczne
    Opis:
    Alumina/copper composites are used where high thermal conductivity, high absorption and dissipation of heat, high resistance to thermal fatigue and good frictional wear resistance are required. The properties of these composites depend on a number of factors including the content, shape and distribution of the ceramic phase, the method of their obtaining, as well as the conditions under which they are obtained. All these variables have influence on mentioned properties and, in consequence, on the future applications of the final material. The aim of this paper was to develop Cu /Al2 O3 composites, processed using two techniques, namely sintering (of Cu /Al2 O3 high-energy mixed powders) and tape casting (of slurry of the following composition: 1, 3 and 5 vol.% of Al2 O3 phase; the remaining part: Cu). The compositions were determined taking into consideration the planned applications. The paper presents newly developed technologies, the results of both microstructure investigations as well as of the measurements of selected physical and mechanical properties (microhardness, wear resistance, thermal conductivity etc.) and contains the analysis of the influence of selected techniques and processing conditions on the properties and the interface morphology between ceramic and copper.
    Kompozyty na bazie miedzi znajdują zastosowanie tam, gdzie jest wymagane: wysokie przewodnictwo cieplne, wysoka absorpcja i rozpraszanie ciepła, wysoka odporność na zmęczenie cieplne i dobra odporność na zużycie ścierne. Właściwości tych kompozytów zależą od wielu czynników tj. zawartości, kształtu i rozkładu fazy ceramicznej w metalowej osnowie jak również od samego sposobu (warunków) ich wytwarzania. Celem niniejszej pracy było otrzymanie kompozytów Cu-Al2 O3 stosując dwie techniki: spiekania mieszaniny proszków pod ciśnieniem oraz odlewanie folii kompozytowych (tape casting), laminowanie oraz końcowe spiekanie otrzymanych materiałów. Ze względu na przyszłe zastosowania tych kompozytów (m.in. elementy w układach turbin w samolotach) wytypowane zostały następujące składy: 99%ob j:Cu-1%ob j:Al2 O3 , 97%ob j:Cu-3%ob j: Al2 O3 , 95%ob j:Cu-5%ob j: Al2 O3 : W prezentowanej pracy przedstawiono dwie technologie otrzymania kompozytów na bazie miedzi. Przeprowadzone zostały badania mikrostruktury otrzymanych kompozytów ze szczególnym zwróceniem uwagi na możliwość pojawienia się warstwy przejściowej ceramika/metal. Przeprowadzone zostały również badania właściwości fizycznych (twardość, gęstość), badania właściwości cieplnych (dyfuzyjność cieplna, przewodnictwo cieplne) oraz badania właściwości mechanicznych (zużycie ścierne) otrzymanych kompozytów.
    Źródło:
    Archives of Metallurgy and Materials; 2014, 59, 4; 1301-1306
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Mechanical Characteristics of Ductile Iron Determined in an Original Modified Low Cycle test
    Autorzy:
    Maj, M.
    Pietrzak, K.
    Klasik, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/379780.pdf
    Data publikacji:
    2019
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    iron
    mechanical properties
    microstructure
    żelazo
    właściwości mechaniczne
    mikrostruktura
    Opis:
    The results presented in this article are part of the research on fatigue life of various foundry alloys carried out in recent years in the Lukasiewicz Research Network – Institute of Precision Mechanics and AGH University of Science and Technology, Faculty of Foundry Engineering. The article discusses the test results obtained for the EN-GJS-600-3 cast iron in an original modified low-cycle fatigue test (MLCF), which seems to be a beneficial research tool allowing its users to evaluate the mechanical properties of materials with microstructural heterogeneities under both static and dynamic loads. For a comprehensive analysis of the mechanical behaviour with a focus on fatigue life of alloys, an original modified low cycle fatigue method (MLCF) adapted to the actually available test machine was used. The results of metallographic examinations carried out by light microscopy were also presented. From the analysis of the results of the conducted mechanical tests and structural examinations it follows that the MLCF method is fully applicable in a quick and economically justified assessment of the quality of ductile iron after normalizing treatment.
    Źródło:
    Archives of Foundry Engineering; 2019, 4; 27-32
    1897-3310
    2299-2944
    Pojawia się w:
    Archives of Foundry Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Material investigations of composites and their selected applications in motor transport
    Autorzy:
    Rudnik, D.
    Pietrzak, K.
    Wojciechowski, A.
    Sobczak, J.
    Kowalewski, Z. L.
    Powiązania:
    https://bibliotekanauki.pl/articles/243917.pdf
    Data publikacji:
    2008
    Wydawca:
    Instytut Techniczny Wojsk Lotniczych
    Tematy:
    metal matrix composites
    microstructure
    properties
    applications
    Opis:
    The paper presents advances in the range of brake discs and engine pistons production using metal matrix composites and identifies their advantages in comparison to materials traditionally applied. The wear characteristics in the case of brake discs and thermal shock resistance in the case of pistons were determined. The wear was assessed by measurements of friction coefficients in different temperatures. The thermal shock resistance was described as the crack length formed during the tests. The image analysis was used in the quantitative microstructure assessments for determination of synthetic geometrical parameter correlated with composites properties. The two synthetic geometrical variables have been proposed in the microstructure description of a new generation brake discs and pistons. The selected relationships between functional properties and composite microstructure are presented. It was shown that a life of brake discs made from A359 aluminum alloy reinforced by SiC precipitates is much longer in comparison to traditional, made from cast iron. It was ascertained also that the best thermal shock resistance was obtained in the case of AK12 composite with Al2O3 short fibers in cast heat treated. The results may be treated as the base for the recommendations of tested metal matrix composites for applicability in selected vehicle parts and subsets producing.
    Źródło:
    Journal of KONES; 2008, 15, 2; 399-407
    1231-4005
    2354-0133
    Pojawia się w:
    Journal of KONES
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The relationship between microstructure and mechanical properties of directly bonded copper-alumina ceramics joints
    Autorzy:
    Pietrzak, K.
    Olesińska, W.
    Kaliński, D.
    Strojny-Nędza, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/199776.pdf
    Data publikacji:
    2014
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    directly bonded copper-alumina ceramics joints
    Opis:
    The effect of phase transformations induced in the surface layer of alumina ceramics during its direct joining with copper activated with oxygen or titanium on the mechanical strength of the ceramic/copper joints was examined. The materials used in the experiments were an alumina single crystal, alumina ceramics (97.5 wt% Al2O3), the cermet mixtures: Cu-Cu2O with 10-50 wt% of Cu2O, copper with 5 wt% of Ti, and copper with 5 wt% of Ti and 10 wt% of Ag. The microstructure of the transition layer was examined by the X-ray diffraction method (XRD), scanning electron microscopy method (SEM) and energy dispersive x-ray spectroscopy (EDX). The mechanical strength of the joints was measured using the three-point bending method. The amount of oxygen optimal for the joining process was determined. It has been demonstrated that the cohesion of the joints depends not only on the formation of the individual phases but also, or even primarily, on the microstructure of the transition layer formed between them.
    Źródło:
    Bulletin of the Polish Academy of Sciences. Technical Sciences; 2014, 62, 1; 23-32
    0239-7528
    Pojawia się w:
    Bulletin of the Polish Academy of Sciences. Technical Sciences
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Copper-Carbon Nanoforms Composites - Processing, Microstructure and Thermal Properties
    Autorzy:
    Pietrzak, K.
    Gładki, A.
    Frydman, K.
    Wójcik-Grzybek, D.
    Strojny-Nędza, A.
    Wejrzanowski, T.
    Powiązania:
    https://bibliotekanauki.pl/articles/350995.pdf
    Data publikacji:
    2017
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    metal matrix composite
    sintering
    copper
    graphene
    thermal diffusivity
    Opis:
    The main current of publication is focused around the issues and problems associated with the formation of composite materials with Cu matrix and reinforcing phases in the various carbon nanoforms. The core of the research has been focused on thermal conductivity of these composites types. This parameter globally reflects the state of the structure, quality of raw materials and the technology used during the formation of composite materials. Vanishingly low affinity of copper for carbon, multilayered forms of graphene, the existence of critical values of graphene volume in the composite are not conducive to the classic procedures of composites designing. As a result, the expected, significant increase in thermal conductivity of composites is not greater than for pure copper matrix. Present paper especially includes: (i) data of obtaining procedure of copper/graphene mixtures, (ii) data of sintering process, (iii) the results of structure investigations and of thermal properties. Structural analysis revealed the homogenous distribution of graphene in copper matrix, the thermal analysis indicate the existence of carbon phase critical concentration, where improvement of thermal diffusivity to pure copper can occur.
    Źródło:
    Archives of Metallurgy and Materials; 2017, 62, 2B; 1307-1310
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Microstructural Aspects of Fatigue Parameters of Lead-Free Sn-Zn Solders with Various Zn Content
    Autorzy:
    Pietrzak, K.
    Klasik, A.
    Maj, M.
    Wojciechowski, A.
    Sobczak, N.
    Powiązania:
    https://bibliotekanauki.pl/articles/379846.pdf
    Data publikacji:
    2017
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    lutowanie bezołowiowe
    mikrostruktura
    właściwości mechaniczne
    lead-free solders
    microstructure
    mechanical properties
    Opis:
    The study includes the results of research conducted on selected lead-free binary solder alloys designed for operation at high temperatures. The results of qualitative and quantitative metallographic examinations of SnZn alloys with various Zn content are presented. The quantitative microstructure analysis was carried out using a combinatorial method based on phase quanta theory, according to which any microstructure can be treated as an array of elements disposed in the matrix material. Fatigue tests were also performed using the capabilities of a modified version of the LCF method hereinafter referred to in short as MLCF, which is particularly useful in the estimation of mechanical parameters when there are difficulties in obtaining a large number of samples normally required for the LCF test. The fatigue life of alloys was analyzed in the context of their microstructure. It has been shown that the mechanical properties are improved with the Zn content increasing in the alloy. However, the best properties were obtained in the alloy with a chemical composition close to the eutectic system, when the Zn-rich precipitates showed the most preferred morphological characteristics. At higher content of Zn, a strong structural notch was formed in the alloy as a consequence of the formation in the microstructure of a large amount of the needle-like Zn-rich precipitates deteriorating the mechanical characteristics. Thus, the results obtained during previous own studies, which in the field of mechanical testing were based on static tensile test only, have been confirmed. It is interesting to note that during fatigue testing, both significant strengthening and weakening of the examined material can be expected. The results of fatigue tests performed on SnZn alloys have proved that in this particular case the material was softened.
    Źródło:
    Archives of Foundry Engineering; 2017, 17, 1; 131-136
    1897-3310
    2299-2944
    Pojawia się w:
    Archives of Foundry Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Microstructural Aspects of Fatigue Life of Sn-Zn Lead-free Solders with 1% of Ag Addition
    Autorzy:
    Pietrzak, K.
    Klasik, A.
    Maj, M.
    Sobczak, N.
    Wojciechowski, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/382245.pdf
    Data publikacji:
    2018
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    lead-free solders
    microstructure
    mechanical properties
    lutowanie bezołowiowe
    mikrostruktura
    właściwości mechaniczne
    Opis:
    The article presents the study results of Sn-Zn lead-free solders with the various Zn content. The results concern the hypoeutectic, eutectic and hypereutectic alloys containing respectively 4.5% Zn, 9% Zn and 13.5% Zn. Moreover, these alloys contain the constant Ag (1%) addition. The aim of the study was to determine the microstructural conditionings of their fatigue life. In particular it was focused on answer the question what meaning can be assigned to the Ag addition in the chemical composition of binary Sn-Zn alloys. The research includes a qualitative and quantitative assessments of the alloy microstructures, that have been carried out in the field of light microscopy (LM). In order to determine some geometrical parameters of the microstructure of alloys the combinatorial method based on the phase quanta theory was applied. Moreover, for the identification necessities the chemical analyses in the micro-areas by SEM/EDS technics were also performed. Based on the SEM/EDS results the phases and intermetallic compounds existing in the examined lead-free solders were identified. The mechanical characteristics were determined by means of the modified low cycle test (MLCF). Based on this method and on the results obtained every time from only one sample the dozen of essential mechanical parameters were evaluated. The research results were the basis of analyzes concerning the effects of microstructural geometrical parameters of lead-free alloys studied on their fatigue life at ambient temperature.
    Źródło:
    Archives of Foundry Engineering; 2018, 18, 1; 87-92
    1897-3310
    2299-2944
    Pojawia się w:
    Archives of Foundry Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Powłoki WC-a:C i MoS2 (Ti, W) na stopie Inconel 600 przeznaczone do pracy w łożyskach foliowych
    WC-a:C and MoS2 (Ti, W) layers on Inconel 600 alloy for foil bearing elements
    Autorzy:
    Pietrzak, K.
    Chmielewski, M.
    Piekoszewski, W.
    Michalczewski, R.
    Mańkowska-Snopczyńska, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/192108.pdf
    Data publikacji:
    2014
    Wydawca:
    Sieć Badawcza Łukasiewicz - Instytut Technologii Materiałów Elektronicznych
    Tematy:
    łożyska foliowe
    rozpylanie magnetronowe
    warstwy
    mikrostruktura
    właściwości trybologiczne
    foil bearings
    magnetron sputtering
    layers
    microstructure
    tribological properties
    Opis:
    Łożyska foliowe stanowią nowe alternatywne rozwiązanie łożyskowania dla systemów ślizgowych (wymagających smarowania) bądź tocznych szczególnie tam, gdzie z uwagi na warunki pracy (np. temperatura, prędkość obrotowa, środowisko pracy) konwencjonalne rozwiązania nie mogą być stosowane. Jak dotychczas znalazły one zastosowanie m.in. w turbinach silników odrzutowych, mikroturbinach, pompach, sprężarkach, etc. W celu rozszerzenia możliwości ich stosowanie, na świecie prowadzone są badania skoncentrowane w głównej mierze na opracowaniu nowych materiałów, które mogą spełniać coraz wyższe wymagania (trybologiczne, mechaniczne, cieplne). Jednym z możliwych rozwiązań jest zastosowanie modyfikowanych powierzchniowo, przy zastosowaniu techniki rozpylania magnetronowego, cienkich folii metalowych. W prezentowanej pracy przedstawiono opracowane przez autorów warunki technologiczne modyfikacji stopu Inconel 600, poprzez wytworzenia dwóch rodzajów powłok (WC-a:C oraz MoS2). Przedstawiono również wyniki badań mikrostruktury powłok i podłoża po procesie osadzania oraz porównano właściwości trybologiczne opracowanych powłok z właściwościami charakterystycznymi dla niemodyfikowanego materiału podłoża.
    Foil bearings are a new, alternative solution to apply to systems for which conventional oil-lubricated or rolling element bearings are unsuitable due to their operational conditions such as the temperature, rotational speed, working environment, etc. There are many possible applications of foil bearings, including aircraft gas turbine engines, auxiliary power units, microturbines, pumps, compressors, cryogenic turboexpanders and turbochargers. At present, several investigations into the materials that could possibly fulfill many different requirements are being conducted to expand the range of the practical implementations of foil bearings. Both tribological properties (friction coefficient and wear resistance) and thermal properties (thermal conductivity) are claimed to be the most important for obtaining top quality foils. One of the possible solutions in complex systems could be using magnetron sputtering for the surface modification of a foil metallic material. The results of technological tests aimed at producing WC-a:C and MoS2 layers on the Inconel 600 alloy are presented in this work. In addition, the effects of microstructural investigations and tribological tests are show for the two afore mentioned systems and compared with non-modified substrates.
    Źródło:
    Materiały Elektroniczne; 2014, T. 42, nr 1, 1; 13-23
    0209-0058
    Pojawia się w:
    Materiały Elektroniczne
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-15 z 15

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