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PL
W silnikach, w których stosuje się zasilanie sprężonym gazem ziemnym, LPG oraz innymi paliwami gazowymi, obserwuje się konieczność częstszej wymiany zaworów wydechowych. Zawory te w silnikach spalinowych mogą być eksploatowane przez krótszy czas niż ich odpowiedniki w silnikach zasilanych benzyną i olejem napędowym. Najbardziej narażona na degradację jest przylgnia zaworu wydechowego. Wynika to z temperatury spalania gazu ziemnego w komorze spalania oraz temperatury spalin mających kontakt z zaworem. W pracy przedstawiono porównawczy rozkład mikrotwardości w zaworach wydechowych napawanych fazą międzymetaliczną Fe3Al oraz stellitem.
EN
In engines, fuelled with concentrated natural gas, LPG, and other gaseous fuels, the necessity for more frequent replacement of exhaust valves is observed. These valves in combustion engines may be operated for a shorter period than their equivalents in engines fuelled with petrol and diesel oil. The exhaust valve face is most exposed to degradation. This results from the combustion temperature of natural gas in the combustion chamber and the temperature of exhaust gas in contact with the valve. The paper presents a comparative distribution of microhardness in exhaust valves pad welded with Fe3Al intermetallic phase and stellite.
EN
The purpose of this study is to elucidate the flow features of the dissimilar Al-Cu welded plates. The welding method used is Bobbin Friction Stir Welding (BFSW), and the joint is between two dissimilar materials, aluminium alloy (AA6082-T6) and pure copper. Weld samples were cut from along the weld line, and the cross-sections were polished and observed under an optical microscope (OM). Particular regions of interest were examined under a scanning electron microscope (SEM) and analysed with Energy Dispersive X-ray Spectroscopy (EDS) using the AZtec software from Oxford Instruments. The results and images attained were compared to other similar studies. The reason for fracture was mainly attributed to the welding parameters used; a higher rotational speed may be required to achieve a successful BFSW between these two materials. The impact of welding parameters on the Al-Cu flow bonding and evolution of the intermetallic compounds were identified by studying the interfacial microstructure at the location of the tool action. The work makes an original contribution to identifying the solid-phase hybrid bonding in Al-Cu joints to improve the understanding of the flow behaviours during the BFSW welding process. The microstructural evolution of the dissimilar weld has made it possible to develop a physical model proposed for the flow failure mechanism.
PL
Ciągły wzrost zapotrzebowania na powłoki aluminiowe dla przemysłu motoryzacyjnego wiąże się z koniecznością poprawy ich jakości w zakresie właściwości ochronnych i mechanicznych. W powłokach aluminiowych, wytworzonych ogniowo, na granicy ze stalowym podłożem powstają fazy pośrednie FeAl3 i Fe2Al5, które zmniejszają odporność na korozję i ograniczają możliwości kształtowania pokrytego wyrobu. W pracy dokonano określenia wpływu dodatku 7% Si do aluminiowej powłoki (690°C/60 s) na jej mikrostrukturę, grubość i rodzaj faz pośrednich oraz twardość i cechy powierzchni. Wykazano, że dodatek Si powoduje 40% zwiększenie twardości powłoki oraz zmniejszenie jej chropowatości. Dodatkowo, zostaje ograniczona dyfuzja wzajemna Al i Fe, w wyniku czego formuje się warstwa faz międzymetalicznych, wzbogacona w fazę Al7-9Fe2Si, 4-krotnie cieńsza niż w powłoce bez dodatku Si, przy zachowaniu grubości zewnętrznej warstwy powłoki.
EN
The continuous increase in demand for aluminum coatings for the automotive industry is associated with the need to improve their quality in terms of protective and mechanical properties. The aluminum coatings produced hot-dip, on the border with the steel substrate formed intermediate phases FeAl3, and Fe2Al5, which reduce the corrosion resistance and limit the possibility of forming a coated article. The paper determines the effect of the addition of 7% Si to an aluminum coating (690°C/60 s) on the microstructure thickness and type of intermediate phases as well as hardness and surface features. It has been shown that the addition of Si results in a 40 % increase in the hardness of the coating and reduce the surface roughness. In addition, is limited interdiffusion of Al and Fe, as a result of which an intermetallic phase layer is formed, Al7-9Fe2Si enriched phase, 4 times thinner than a coating without the addition of Si, while maintaining the thickness of the outer coating layer.
PL
Powłoki ochronne zapewniają ochronę konstrukcji przed korozją, ale także mają na celu spełnienie wymogów marketingowych – walory dekoracyjne. Jednym z przedstawicielem powłok ochronnych, są powłoki ogniowe na bazie Al i Al-Si, które znalazły zastosowanie m. in. w przemyśle motoryzacyjnym. Wytwarzanie powłok Al-Si metodą ogniową (alias: zanurzeniowa), polega na zanurzeniu, uprzednio odtłuszczonego detalu w kąpieli roztopionego metalu powłokowego. Powłoki Al-Si nanoszone są na stale, a połączenie pomiędzy powłoką a podłożem zapewnione jest poprzez wzajemną dyfuzję aluminium i żelaza, co prowadzi do wytworzenia faz międzymetalicznych. W pracy badaniom poddano powłoki Al-Si stosowane w przemyśle motoryzacyjnym. Badania objęły ocenę powłok pod względem ukształtowania struktury, twardości, rozkładu pierwiastków, czy stanu powierzchni (chropowatość). Skład chemiczny powłok określono wykorzystując mikroanalizę EDX, a skład fazowy analizą dyfraktometryczną. Finalną ocenę stanowiło wpływ gięcia na jakość połączenia pomiędzy podłożem a powłoką.
EN
Protective coatings provide protection of structures against corrosion, but they also aim to meet marketing requirements – decorative qualities. One of the representatives of protective coatings are fire coatings based on Al and Al-Si, which have been used, among others, in the automotive industry. The production of Al-Si coatings using the fire method (known as: immersion) consists in immersing a previously degreased detail in a bath of molten coating metal. Al-Si coatings are applied permanently, and the connection between the coating and the substrate is ensured by the mutual diffusion of aluminum and iron, which leads to the formation of intermetallic phases. The study examines Al-Si coatings used in the automotive industry. The research included assessment of coatings in terms of structure, hardness distribution of elements, and surface condition (roughness). The chemical composition of the coatings was determined using EDX microanalysis and phase composition by diffractometric analysis. The final assessment focused on the impact of bending on the quality of the connection between the substrate and the coating.
5
Content available remote Ocena mikrostruktury napoiny ze srebra na tytanie
PL
W pracy podjęto próbę oceny mikrostruktury napoiny wykonanej z drutu srebrnego na blachach tytanowych. Ocenę przeprowadzono z wykorzystaniem mikroskopii świetlnej i skaningowej mikroskopii elektronowej. Ujawnione wyniki obserwacji wskazują na występowanie złożonej struktury płytkowej w obszarze materiału rodzimego (tytanu) i budowę dendrytyczną w napoinie.
EN
The microstructure of Ag on Ti plate padding weld was investigated in the paper. The evaluation was carried out using light microscopy and scanning electron microscopy. Observation results indicate the presence of a complex lamellar structure in the area of the native material (titanium) and dendritic structure in the clad.
6
Content available remote Natryskiwanie łukowe powłok Fe-Al
PL
W artykule przedstawiono wstępne wyniki badań wytwarzania kompozytowych powłok z układu Fe-Al z udziałem faz międzymetalicznych in-situ za pomocą natryskiwania łukowego. Proces natryskiwania prowadzono poprzez jednoczesne topienie dwóch różnych drutów elektrodowych, aluminiowego i stalowego. Celem prowadzonych badań jest wytworzenie powłok ochronnych o kompozytowej strukturze ze znaczącym udziałem faz międzymetalicznych FexAly, których synteza zachodzi podczas procesu natryskiwania (in-situ). Otrzymane wyniki wykazały lokalne występowanie faz międzymetalicznych z układu Fe-Al, a dominujące składniki struktury to roztwory aluminium w żelazie i żelaza w aluminium. Udział faz międzymetalicznych w powłoce jest stosunkowo niski, lecz jego wpływ na właściwości materiału powłoki jest istotny.
EN
The paper presents preliminary results of research on the production of composite coatings from the Fe-Al system with participation of intermetallic phases in-situ using arc spraying. The spraying process was carried out by simultaneously melting two different electrode wires, aluminium and steel. The aim of the research is to create protective coatings with a composite structure with a significant participation of FexAly as a intermetallic phases reinforcement. The synthesis of intermetallic takes place during the (in-situ) spraying process. Currently most of coatings involving intermetallic phases are being manufactured by different thermal spraying methods using coating materials in form of prefabricated powders containing intermetallic phases. The obtained results showed that the local occurrence of intermetallic phases from the Fe-Al system, and the dominant components of the structure are two phases, aluminium solid solutions in iron and iron in aluminium. The participation of intermetallic phases in the coating is relatively low, but it’s effect on the properties of the coating material is significant.
EN
The research described in this contribution is focused on fractographic analysis of the fracture area of newly developed eutectic silumin type AlSi9NiCuMg0.5 (AA 4032), which was developed and patented by a team of staff of the Faculty of Mechanical Engineering. The paper presents determination of the cause of casting cracks in operating conditions. Fractographic analysis of the fracture area, identification of the structure of the casting, identification of structural components on the surface of the fracture surface and chemical analysis of the material in the area of refraction were performed within the experiment. Al-Si alloys with high specific strength, low density, and good castability are widely used in pressure-molded components for the automotive and aerospace industries. The results shown that the inter-media phases Fe-Al and Fe-Si in aluminium alloys lead to breakage across the entire casting section and a crack that crossed the entire cross section, which was confirmed by EDS analysis.
PL
Wdrożenie nowych materiałów do praktyki przemysłowej pozwala na konstrukcję trwalszych i bardziej wytrzymałych części maszyn przeznaczonych do pracy w wysokiej temperaturze oraz ekstremalnych warunkach. W artykule analizowano zastosowanie metody napawania do wykonania napoiny ze stopu na osnowie fazy międzymetalicznej Fe40Al5CrTiB na powierzchni stali S235JR. Proces prowadzono metodą TIG w atmosferze gazu obojętnego przy zastosowaniu prądu stałego (DC-). Próbki napawano w trzech wariantach: jednościegowym, wielościegowym oraz wielowarstwowym. Po procesie napawania przeprowadzono badania za pomocą mikroskopu świetlnego (LM), elektronowego mikroskopu skaningowego oraz dokonano pomiarów twardości metodą Vickersa (HV). Technologia ta może być zastosowana w przyszłości, na przykład w przemyśle energetycznym do wytworzenia powierzchni żaroodpornych.
EN
Implementation of new materials into industrial practice allows to build more durable and reliable machine parts suitable to operate at high temperature and other special conditions. The paper analyzes implementation of welding method to make intermetallic surface Fe40Al5CrTiB on material grade S235JR. The process was made with tungsten inert gas (TIG) and with the use of reserved polarity direct current (DC-). Welded sample was made as: single bead, multi bead and as multilayer. After the welding process, samples were tested with light microscopy (LM), scanning electron microscopy (SEM) and Vickers hardness (HV). This technology can by used to develop resistance surfaced in the power industry in the future.
EN
The use of secondary aluminum alloys is increasing because it contributes to the decrease of production costs. However, these alloys contain bigger amount of iron. Iron has a negative effect and therefore its elimination is necessary in order to add some elements, which are also called correctors of iron. The most frequently used corrector is manganese. Another quite often used correctors are chromium, potassium, magnesium, vanadium. In the following work, vanadium is used as a corrector of iron phases. The application of vanadium in aluminum alloys has a positive impact on their mechanical properties, increases the tensile strength, ductility and hardness. As experimental material AlSi6Cu4 alloy was used. It was alloyed by master alloy AlFe10. After adding to the master alloy the iron content, the critical value in the alloy exceeded. Vanadium was added to AlSi6Cu4 alloy in different quantities. The image analysis (software NIS-Elements) was used for quantifying the amount of iron based intermetallic phases and determination of average values.
10
Content available remote In situ TEM observation of reaction of Ti/Al multilayers
EN
The Ti/Al multilayers of nominal periods λ = 50 nm and λ = 200 nm were deposited using double target magnetron system equipped with rotating substrate holder. The in situ TEM experiments were aimed at explaining DSC measured exothermic effects through phase transformations taking place during heating of the multilayers with small and large period. Thin foils for these examinations were cut with FIB. The performed experiments showed that the as deposited multilayers are characterized by presence of coarse pseudo-columnar crystallites built of alternating hex-Ti and fcc-Al. The intermixed region at the internal interfaces extends up to 10 nm, i.e. the areas filled with mutually alloyed material starts to dominate over those of pure metals for multilayers of λ < 30 nm. The DSC measurements indicated that in both multilayers their reaction are split to two stages, but those in the small period take place at much lower temperature range, than that in the large period one.
PL
W artykule przedstawiono wyniki badań dotyczących przyczyn pękania lutospoin w różnoimiennych złączach zakładkowych wykonanych laserem diodowym dużej mocy ROFIN DL 020 z użyciem materiału dodatkowego w postaci proszku aluminium, na przykładzie łączenia cienkiej blachy aluminiowej z blachą stalową pokrytą elektrolitycznie powłoką cynkową. Przedstawiono wyniki badań metalograficznych makroskopowych i mikroskopowych. Wskazano na problemy oraz przedstawiono sugestie dotyczące technologii lutospawania laserowego materiałów znacznie różniących się własnościami fizycznymi i składem chemicznym.
EN
A study on cracking phenomena during laser braze welding of dissimilar lap joints between aluminum thin plate and galvanized low carbon sheet steel is described. The experiments were carried out using a high power diode laser Rofin DL020 and aluminum powder as filler metal. Macro and microstructure analysis of the joints were analysed. Issues and problems in laser braze welding of materials having different chemical composition and physical properties are presented.
PL
W artykule przedstawiono wyniki badań dotyczących skłonności do tworzenia się pęknięć w lutospoinach złączy zakładkowych cienkich blach aluminiowych i karoseryjnych blach stalowych obustronnie galwanizowanych cynkiem, które wykonywano laserem diodowym dużej mocy (HPDL) ROFIN DL 020 oraz łukowo metodą CMT z użyciem materiału dodatkowego odpowiednio w postaci proszku i drutu litego. Przedstawiono wyniki badań metalograficznych makroskopowych i mikroskopowych, rentgenografii strukturalnej, mikroanalizy rentgenowskiej EDS oraz pomiarów twardości. Wskazano na przyczyny powstawania w lutospoinach na osnowie aluminium, złączy różnoimiennych typu aluminium - ocynkowana stal niestopowa, kruchych faz międzymetalicznych typu Fe-Al.
EN
In this article results of studies on cracks formation susceptibility in braze-welded joints of thin aluminum sheets and double-sided zinc galvanized steel sheets for car body parts made by laser brazing with high power diode laser ROFIN DL 020 and CMT MIG-brazing, with filler material in form of powder and wire accordingly, were presented. Results of macro- and microscopic metallographic examinations, structural roentgenography, EDS microanalysis and hardness tests were presented. Causes of brittle intermetallic Fe-Al phases formation in Al-matrix filler metal in dissimilar aluminum - zinc plated carbon steel joints were pointed.
EN
Purpose: The aim of this study was to examine the structural and mechanical properties of coatings formed on CuAl2 in-situ reinforced aluminium matrix composites (AMCs) by micro arc oxidation (MAO) process. AMC, which were fabricated by powder metallurgy method upon addition of copper powder into aluminium powder at different percentages (0%, 15 wt.% and 30 wt.%), were exposed to MAO after sintering at 550°C for 6 h. During sintering process CuAl2 type intermetallic was precipitated in the microstructure of copper containing compacts. MAO caused covering of the surfaces of AMCs with an oxide layer mostly consisting of mullite and alumina. Mechanical performance of the coatings were determined by hardness measurements and wear tests. In summary, the oxide layers formed on the AMCs exhibit a reduction in hardness and tribological performance with increasing copper content of the AMC.
EN
The cooling rate is one of the main tools available to the process engineer by means of which it is possible to influence the crystallisation process. Imposing a desired microstructure on a casting as early as in the casting solidification phase widens significantly the scope of technological options at disposal in the process of aluminium-silicon alloy parts design and application. By changing the cooling rate it is possible to influence the course of the crystallisation process and thus also the material properties of individual microstructure components. In the study reported in this paper it has been found that the increase of cooling rate within the range of solidification temperatures of a complex aluminium-silicon alloy resulted in a decrease of values of the instrumented indentation hardness (HIT) and the instrumented indentation elastic modulus (EIT) characterising the intermetallic phase occurring in the form of polygons, rich in aluminium, iron, silicon, manganese, and chromium, containing also copper, nickel, and vanadium. Increased cooling rate resulted in supersaturation of the matrix with alloying elements.
EN
Al-enriched layer was formed on a magnesium substrate with use of casting. The magnesium melt was cast into a steel mould with an aluminium insert placed inside. Different conditions of the casting process were applied. The reaction between the molten magnesium and the aluminium piece during casting led to the formation of an Al-enriched surface layer on the magnesium substrate. The thickness of the layer was dependent on the casting conditions. In all fabricated layers the following phases were detected: a solid solution of Mg in Al, Al3Mg2, Mg17Al120 and a solid solution of Mg in Al. When the temperature of the melt and the mould was lower (variant 1 – 670oC and 310oC; variant 2 – 680oC and 310oC, respectively) the unreacted thin layer of aluminium was observed in the outer zone. Applying higher temperatures of the melt (685oC) and the mould (325oC) resulted in deep penetration of aluminium into the magnesium substrate. Areas enriched in aluminium were locally observed. The Al-enriched layers composed mainly of Mg-Al intermetallic phases have hardness from 187-256 HV0.1.
16
EN
Purpose: of this paper is to compare some properties of Ti-Al and Ti-Nb alloys to investigate on the possibility to jointly employed them industrially. Ti-Al alloys have been proposed because they present challenging characteristics for high temperature purposes and β type Ti-Nb alloy has specific mechanical properties at room temperature. Ti-Al alloys are very attractive materials and represent one of the most important materials employed for aero jet engines. The most promising alloy belonging to the above mentioned classes are predominantly based on simultaneously presence of two phases, namely γ-TiAl (gamma titanium aluminides) and α2-Ti3Al both with a fully lamellar microstructure and could replace Ni-based superalloys in some high temperature applications in aerospace and automotive industries. The most important advantages of such alloys compared to some superalloys consist in their low density correlated to their superior efficiency in service and reduced gas emission. Design/methodology/approach: The Ti-Al alloy have been produced by gravity casting, using a vibrating furnace, while the Ti-Nb alloy samples have been realized by the cold crucible levitation melting (CCLM) casting technology. Microstructural and mechanical characterization have been performed. Findings: The microstructural analysis for the Ti-Al alloy reveals a fully-lamellar microstructure with alternate plates of α2-(Ti3Al) and γ-(TiAl) plates. The grains have an average size of about 200 μm. For the Ti-Nb based alloy only a β mono-phase has been detected. This alloy has a equiaxed microstructure with an average grain dimension of about 170 μm. The Ti-Nb alloy presents a high mechanical strength while on the contrary that of the Ti-Al has been deleteriously affected by the presence of large gas porosities. Superior hardness values have been reached with Ti-Al alloy, due to the presence of hard γ-TiAl. Practical implications: The most important implication is related to the transfer toward the proper choice of the correct parameters during manufacturing. Originality/value: Investigation on the influence of the elemental composition enriched by other elements and casting processes on the defect development, the microstructural characteristics and on the mechanical behaviour of the alloys.
EN
he work is a continuation of the research carried out on a high-temperature calorimeter solution type on alloys from Ni-Al-Cr system. Thanks to the construction innovation introduced by authors the device allows the determination of the formation enthalpy of alloys at ambient and elevated temperatures. Experiments described in this article were carried out at three temperatures: 873K, 996K and 1150K on the alloys of the chemical compositions from the Ni75Al25 ÷ Ni87Cr13 section of the Ni-Al-Cr system. On the basis of changes in the enthalpy of formation with increasing chromium content of the alloys, points corresponding to places of phase boundaries γ′ / γ′+γ / γ in Ni-Al-Cr system were determined. A similar relationship was observed in previous studies of alloys from Ni75Al25÷Ni75Cr25 section. For precise determination of these characteristic points a statistical model was applied.
PL
Praca jest kontynuacją badań prowadzonych na skonstruowanym przez autorów wysokotemperaturowym kalorymetrze typu rozpuszczania. Urządzenie pozwala na określanie entalpii tworzenia stopów w podwyższonej temperaturze. Opisywane badania przeprowadzono w trzech temperaturach: 873K, 996K i 1150K na stopach o składach chemicznych znajdujących się na linii Ni75Al25÷Ni87Cr13 układu Ni-Al-Cr. Na podstawie zmian wartości entalpii tworzenia wraz ze wzrostem zawartości chromu w stopach stwierdzono istnienie punktów odpowiadających miejscom występowania granic międzyfazowych γ′ / γ′+γ / γ w układzie Ni-Al-Cr. Podobną zależność zaobserwowano w poprzednich badaniach dotyczących obszaru Ni75Al25÷Ni75Cr25. Aby precyzyjnie wyznaczyć te charakterystyczne punkty opracowano i zastosowano model statystyczny.
EN
Silicon cast iron with high chemical resistance, which is the biggest advantage of this material, did not have any competition for a long time. It was popular on the market of metal materials because of its low price. However, the production of this material requires special attention and precautions, which is a barrier for foundry. The article presents the results of research of high silicon cast iron crystallization based on thermal derivative analysis (which has identified characteristic temperatures of the investigated alloy crystallization process basis on the part of Fe–Si phase diagram and process analysis using calculations made in Thermo–Calc software) and metallographic analysis of the structure.
EN
Available technical literature includes a number of reports on harmful effects connected with elevated content of iron in aluminium-silicon alloys but in case of pressure castings, alloys containing up to 2% Fe can be used. This follows from lesser susceptibility of such alloys to sticking to surfaces of metal moulds. One effect of iron presence in aluminium-silicon alloys is precipitation of iron-rich intermetallic phases. In the study reported in this paper it has been found that in a multicomponent aluminium-silicon alloy, the indentation hardness (HIT) and the elastic indentation modulus (EIT) of intermetallic phases occurring in the form of polyhedrons and/or their conglomerates, rich in aluminium, iron, silicon, manganese, and chromium, containing also copper, nickel, and vanadium, are higher than those measured for silicon crystals. This feature can be used to intentional modelling microstructure of mechanical parts which are expected to show high resistance to abrasive wear.
EN
In this study a simple procedure forthe in situ identification of the intermetallic phase precipitates in the interdendritic eutectic in both wrought and cast AlFeMnSi alloys has been established and then verified by experimental results. Morphology of the phase constituents of these eutectics: A6MnFe, αc-AlFeMnSi, αH-AlFeSi, β-AlFeSi, has been revealed on the metallographic microsections, observed with light and scanning electron microscopes. Chemical composition of these phase precipitates was estimated by means of point x-ray microanalysis. The homogeneity range for particular intermetallic phase precipitates, as influenced by either alloy chemical composition or microstructure morphology, was estimated.
PL
W pracy przedstawiono prostą procedurę identyfikacji in situ wydzieleń faz międzymetalicznych w eutektykach międzydendrytycznych w stopach AlFeMnSi do przeróbki plastycznej i odlewniczych, wraz z jej eksperymentalną weryfikacją. Na podstawie obserwacji mikroskopowych opisano, ujawnioną na zgładach międzymetalicznych, morfologię składników fazowych, występujących w tych eutektykach: A6MnFe, αc-AlFeMnSi, αH-AlFeSi, β-AlFeSi. Do badań wykorzystano mikroskopy: świetlny oraz elektronowy, skaningowy. Skład chemiczny wydzieleń faz międzymetalicznych określono za pomocą punktowej mikroanalizy rentgenowskiej. Zakres zmienności składu chemicznego dla wydzieleń wybranych składników fazowych był analizowany w zależności od składu chemicznego stopu oraz cech morfologicznych mikrostruktury.
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