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PL
W ostatnich latach obserwuje się znaczny wzrost użycia bezzałogowych statków powietrznych (BSP) w licznych zastosowaniach komercyjnych, a także wojskowych. Obecnie szacuje się, że na świecie istnieje przeszło 10 mln tego typu obiektów, wykorzystywanych od celów od hobbystycznych po profesjonalne, których wartość przekracza wiele milionów dolarów. BSP, zwane powszechnie dronami muszą cechować się małą masą i dużą sprawnością układu napędowego i zasilania, które pozwalają na długi czas nieprzerwanej pracy w powietrzu zwiększając obszar potencjalnych zastosowań. Jest to szczególnie istotne w przypadku obiektów latających używanych w zastosowaniach profesjonalnych. W zależności od zastosowania i liczności serii, do ich budowy wykorzystuje się wiele różnych materiałów w szczególności kompozytów. Jednakże bezzałogowe aparaty latające używane do celów militarnych, a także komercyjnych, np. w transporcie i rolnictwie muszą dodatkowo cechować się wytrzymałą i stabilną konstrukcją pozwalającą na przenoszenie dużych obciążeń. Z tej przyczyny coraz częściej do budowy BSP używa się stopów metali lekkich w szczególności aluminium, magnezu i tytanu. Ważnym argumentem przemawiającym za używaniem stopów metali lekkich są również względy ekologiczne gdyż niedostatecznie jeszcze są rozwinięta procesy recyklingu materiałów kompozytowych.
EN
In recent years, there has been a significant increase in the use of unmanned aerial vehicles(UAV) in numerous commercial as well as military applications. Currently, it is estimated that there are more than 10 million such objects in the world, used for purposes ranging from hobby to professional, with a value exceeding many millions of dollars. UAV, commonly referred to as drones, must be characterized by low weight and high efficiency of the propulsion and power systems that allow for long periods of continuous operation in the air increasing the area of potential applications. This is especially important for flying objects used in professional applications. Depending on the application and the number of series, many different materials are used for their construction, especially composites. However, unmanned aerial vehicles used for military as well as commercial purposes, such as transport and agriculture, must additionally feature a robust and stable design to carry heavy loads. For this reason, lightweight metal alloys, in particular aluminum, magnesium and titanium, are increasingly being used to build UAV. An important argument for the use of light alloys are also ecological considerations as recycling processes for composite materials are still underdeveloped.
EN
In the present research, the wear behaviour of magnesium alloy (MA) AZ91D is studied and optimized. MA AZ91D is casted using a die-casting method. The tribology experiments are tested using pin-on-disc tribometer. The input parameters are sliding velocity (1‒3 m/s), load (1‒5 kg), and distance (0.5‒1.5 km). The worn surfaces are characterized by a scanning electron microscope (SEM) with energy dispersive spectroscopy (EDS). The response surface method (RSM) is used for modelling and optimising wear parameters. This quadratic equation and RSM-optimized parameters are used in genetic algorithm (GA). The GA is used to search for the optimum values which give the minimum wear rate and lower coefficient of friction. The developed equations are compared with the experimental values to determine the accuracy of the prediction.
EN
The article discusses the electrodynamic treatment (EDT) of thinwalled welded structures and EDT equipment, presents results of mathematical modelling concerning the effect of EDT on stresses in welded sheets made of aluminium alloy AMg6 as well as discusses the effect of EDT on the plastic strain mechanism. In addition, the article presents tests results concerning the effect of EDT during the welding of ship structures made of AMg6 plates and discusses the role of EDT in bulge formation. In addition, the article discusses the application of EDT during the repair welding of aero-engine nacelles made of magnesium alloy ML10 and the effect of EDT on openings in an airplane wing stinger in relation to its service life.
PL
Omówiono zasadę obróbki elektrodynamicznej (EDT) cienkościennych konstrukcji spawanych i opracowaną aparaturę do EDT. Przedstawiono wyniki modelowania matematycznego wpływu EDT na stan naprężenia spawanej płyty ze stopu AMg6 oraz badań wpływu elektrodynamicznych oddziaływań na mechanizm odkształcenia plastycznego. Podano wyniki wpływu EDT na odkształcenia typu wybrzuszenie powstające podczas spawania konstrukcji okrętowych z blach AMg6. Omówiono przykład zastosowania EDT podczas spawania naprawczego gondoli silnika lotniczego z stopu magnezu ML10 oraz wpływ EDT otworów podłużnicy skrzydła samolotu na trwałość zmęczeniową.
4
Content available remote Biodegradowalne stopy na bazie Zn
PL
Stopy magnezu i cynku mogą być stosowane jako biodegradowalne materiały do produkcji implantów. Dzięki swoim własnościom mechanicznym oraz korozyjnym spełniają stawiane wymagania wytrzymałościowe oraz nie wytwarzają trujących substancji podczas rozpuszczania się w ludzkim ciele.
PL
W artykule przedstawiono wyniki badań dotyczące porównania parametrów struktury geometrycznej powierzchni (SGP) próbek ze stopu magnezu AZ31 po polerowaniu oraz po wytworzeniu na ich powierzchniach różnego typu biokompatybilnych powłok ochronnych. Zakres prezentowanych badań obejmował proces przygotowania próbek do ich cięcia metodą WEDM, polerowania krążkami ściernymi, chemicznego trawienia oraz modyfikację ich powierzchni poprzez wytworzenie biopolimerowych powłok ochronnych metodą chemicznego osadzania z fazy gazowej CVD.
EN
In this paper the results of investigations concerning the comparison of surface geometric structure parameters of samples made of magnesium alloy AZ31 were presented. The samples were polish and coated of various types of biocompatible protective coatings. The scope of presented studies included the process of sample preparation by WEDM cutting, abrasive disc polishing, chemical pickling and modification of their surface by producing biopolymer protective coating by chemical deposition from gas phase (CVD).
EN
The results of the Charpy impact test of AE-type magnesium alloys produced by the high pressure die casting method are presented. Three alloys with different weight fractions of rare earth elements (RE; e.g. 1, 3 and 5 wt%) and the same mass fraction of aluminium (5 wt%) were prepared. The casts were fabricated using a typical cold chamber high pressure die casting machine with a 3.8 MN locking force. Microstructural analyses were performed by means of a scanning electron microscope (SEM). The impact strength (IS) was determined using a Charpy V hammer with an impact energy equal to 150 J. The microstructure of the experimental alloys consisted of an [alpha]-Mg solid solution and Al11RE3, Al10Ce2Mn7 and Al2RE intermetallic compounds. The obtained results show the significant influence of the rare earth elements to aluminium ratio on the impact strength of the investigated materials. Lower the RE/Al ratio in the chemical composition of the alloy results in a higher impact strength of the material.
7
EN
Selective Laser Melting (SLM) of magnesium alloys is the technology undergoing dynamic development in many research centres. The results are promising and make it possible to manufacture defect-free material with better properties than those offered by the manufacturing technologies used to date. This review aims to evaluate present state as well as main challenges of using Laser Powder Bed Fusion (L-PBF) for processing magnesium alloys as an alternative way to conventional technolo-gies to manufacture parts in the aerospace industry. This literature review is the first one to outline information concerning the potential to use magnesium alloys in the aerospace industry as well as to summarise the results of magnesium alloy pro-cessing using AM technologies, in particular L-PBF. The available literature was reviewed to gather information about: the use of magnesium alloys in the aerospace industry-the benefits and limitations of using magnesium and its alloys, examples of applications using new processing methods to manufacture aerospace parts, the benefits and potential of using L-PBF to process metallic materials, examples of the use of L-PBF to manufacture aerospace parts, and state-of-the-art research into L-PBF processing of magnesium and magnesium alloys.
8
Content available remote The microstructure and creep properties of as-cast Mg-Sn-Si-(Al) magnesium alloys
EN
Magnesium alloys containing rare earth metals exhibit good creep resistance up to 300 °C and good tensile properties at ambient temperature. The high cost of rare earth has led to studies regarding the creep resistance of Mg alloys with cheap alloying elements (Sn, Ca, Si) that could be substituted for Mg-RE alloys. In this paper, the influence of Si and Al on microstructure and mechanical properties of Mg-7Sn alloy was investigated using optical (LM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction analysis (XRD), tensile tests and creep tests at 200–250 °C. Microstructure of as-cast alloys consists of α-Mg matrix and intermetallic compounds at the interdendritic regions. Heat treatment consisting of solid solution treatment and ageing increases the tensile properties at ambient temperature due to the precipitation of the fine Mg2Sn phase. The creep resistance of aged Mg-7Sn alloy is poor. The addition of Si and Al to Mg-7Sn alloy has resulted in improving the creep resistance due to the refinement of Mg2Sn phase and the appearance of Mg2Si phase at the grain boundaries. The Mg-7Sn-1Si alloy exhibits better creep resistance at 200 °C than Mg-7Sn-5Si and Mg-7Sn-5Si-2Al alloys. The Mg-7Sn alloys with 5% Si have better creep properties at 250 °C in comparison to Mg-7Sn-1Si alloy.
EN
The quaternary Mg–9Li–2Al–0.5Sc alloy (in wt%) was prepared from pure components. After homogenization, the alloy was subjected to severe plastic deformation by KoBo extrusion and cyclic forging leading to grain refinement in the range of 0.5–2 µm of hexagonal close-packed (HCP) α phase. Deformed alloys showed high ultimate tensile strength near 200 MPa and good elongation in the range 30–40% at room temperature (RT). Large elongations close to 200% were obtained during the tensile test at a temperature of 200 °C. Deformed samples showed the presence of multiple voids confirming grain boundary sliding mechanism of deformation. Twins on {101-2} planes were identified using electron backscatter diffraction analysis, being in a good agreement with the earlier observation of Mg–Li and Mg–Sc alloys. Intermetallic phases such as cubic MgSc were identified in deformed alloys mostly within HCP α phase, whereas HCP MgSc2 particles were observed within body-centered cubic (BCC) β phase. Intermetallic phases were responsible for RT strengthening of alloys and slightly lower tensile elongation during superplastic deformation. Formation of the HCP α phase was observed within the BCC β phase in tensile deformed alloys. Atomic-level nucleation of HCP phase within the β phase was identified by the use of high-resolution transmission electron microscopy technique.
EN
The paper explores the new method of improving the workability of materials in the dieless drawing processes. The proposed method is based on the implementation of a multi-pass incremental deformation. Moreover, in each pass, strain and strain rate sensitivity of flow stress should be positive and significant. An approach based on the finite element calculation of instability coefficient of plastic deformation and simultaneous modeling of material ductility were applied for prediction of the workability. Two dieless drawing processes have been investigated. The difference was related to the heating system-induction heating and laser heating. FE simulations and experimental tests for three materials, two magnesium alloys (MgCa0.8 and MgNi19) and pure copper were performed. It was shown that the most effective increase in workability by multi-pass deformation can be achieved using laser dieless drawing. This is possible due to the shorter heating area and, as a consequence, the larger strain rate, which leads to better stability of the deformation process.
EN
The present study demonstrates the friction stir welding (FSW) process can be used as a mechanical alloying tool to fabricate a solid solution. An attempt has been taken for alloying the AM20 Mg base matrix using Zn at the weld zone during friction stir welding. Successful joints with sound mechanical properties and enhanced quality attributes are observed in the welds. Use of Zn alloying element at the nugget zone, the joint efficiency reached 90% to that of the base material and also which is about 25% more than the strength obtained in the case of without alloying element set of experiments. The addition of Zn alloy to Mg substrate forms Mg–Zn binary solid solution reinforcing intermetallic compounds, namely MgZn and Mg7Zn3 resulting in improved joint properties. This research work also reports the investigative outcomes, namely flow in the joint area, metallurgical deviation, microstructural modification, and diffusion of the constituent alloying element during the welding process. The targeted objective was effectively accomplished and the Zn alloyed stir area can fulfil the required application. The findings from the selective alloying process may be relevant for the implementation of industrial users over Mg alloys using a FSW process with better weldability and improved strength.
EN
The research is focused on the study of the temperature dependence of the internal damping of selected magnesium alloys with different contents of aluminium - AZ31 and AZ61. These alloys are currently widely used in various types of industry, mainly in the automotive industry. It belongs to a group of materials called HIDAMETS because they have excellent damping properties. The internal damping of the samples was measured on a unique ultrasonic device constructed at Žilina University in Žilina. Specimens were measured at baseline in the temperature range from 25 °C to 400 °C. Changes in internal damping caused by varying aluminium contents in investigated alloys were noted. As the aluminium content increases, maximum internal damping is achieved due to the formation, growth and subsequent dissolution of the continuous precipitate in the microstructure.
EN
The thermochemical treatment applied to improve the surface properties of AZ91 consisted in heating the material in contact with AlSi10Mg powder at 445 oC for 30 min. During heat treatment process the powder was held under pressure to facilitate the diffusion of the alloying elements to the substrate and, accordingly, the formation of a modified layer. Two pressures, 1 MPa and 5 MPa, were tested. The resultant layers, containing hard Mg2Si and Mg17Al12 phases, were examined using an optical microscope and a scanning electron microscope equipped with an energy-dispersive X-ray spectrometer (EDS). The experimental data show that the layer microstructure was dependent on the pressure applied. A thicker, three-zone layer (about 200 μm) was obtained at 1 MPa. At the top, there were Mg2Si phase particles distributed over the Mg17Al12 intermetallic phase matrix. The next zone was a eutectic (Mg17Al12 and a solid solution of Al in Mg) with Mg2Si phase particles embedded in it. Finally, the area closest to the AZ91 substrate was a eutectic not including the Mg2Si phase particles. By contrast, the layer produced at a pressure of 5 MPa had lower thickness of approx. 150 μm and a two-zone structure. Mg2Si phase particles were present in both zones. In the upper zone, Mg2Si phase particles were regularly distributed over the Mg17Al12 intermetallic phase matrix. The lower zone, adjacent to the AZ91, was characterized by a higher volume fraction of Mg2Si phase particles distributed over the matrix composed mainly of Mg17Al12. The alloyed layers enriched with Al and Si had much higher hardness than the AZ91 substrate.
PL
W artykule przedstawiono analizę struktury złącza stop aluminium (PA38)–stop magnezu (AZ31) wytworzonego metodą zgrzewania dyfuzyjnego. Za pomocą mikroskopu optycznego i elektronowego mikroskopu skaningowego przeprowadzono szczegółowe badania metalograficzne. Skład chemiczny strefy złącza określono metodą mikroanalizy rentgenowskiej (EDS). Wykonano również pomiary mikrotwardości metodą Vickersa łączonych materiałów i strefy złącza. W wyniku procesu zgrzewania uzyskano trwałe połączenie. Strefa złącza, o grubości ok. 50 µm, miała budowę dwuwarstwową. Od strony stopu PA38 w złączu zidentyfikowano grubszą warstwę (ok. 40 µm) fazy międzymetalicznej Al3Mg2, od strony stopu AZ31 cieńszą warstwę (ok. 10 µm) fazy międzymetalicznej Mg17Al12. W mikrostrukturze strefy złącza od strony stopu PA38 na tle osnowy fazy Al3Mg2 stwierdzono obecność drobnych cząstek fazy Mg2Si. Od strony stopu AZ31, na tle fazy Mg17Al12, obserwowano lokalnie iglaste cząstki fazy Al-Mn-Si. Na podstawie pomiarów mikrotwardości stwierdzono, że strefa złącza zbudowana głównie z faz międzymetalicznych Mg-Al charakteryzuje się kilkukrotnie wyższą mikrotwardością w porównaniu z łączonymi stopami.
EN
This paper presents the results of the microstructure investigation of the aluminium alloy (PA38) – magnesium alloy (AZ31) joint fabricated by diffusion bonding. The structure of the bonding zone was examined using optical microscopy and scanning electron microscopy. The chemical composition of the bonding zone was determined by energy dispersive X-ray microanalysis. The microhardness measurements of the alloys and the bonding zone was also conducted. As a result of the diffusion bonding process the alloys were joined together. The bonding zone with a thickness of about 50μm had two-layer structure. In the bonding zone the thicker layer (about 40μm) of Al3Mg2 intermetallic phase was observed on the PA38 alloy side. The thinner layer (about 10 μm) of Mg17Al12 intermetallic phase was observed on the AZ31 alloy side. In the area of the bonding zone close to the PA38 alloy fine particles of Mg2Si phase were found in the matrix of Al3Mg2. In the bonding zone close to the AZ31 alloy locally a needle-shaped particles of the Al-Mn-Si phase were observed over the Mg17Al12 phase matrix. The results of microhardness measurement revealed that the bonding zone composed mainly of Mg-Al intermetallic phases layers had much higher microhardness than the joined alloys.
15
Content available remote Odporność odlewniczego stopu magnezu AZ91 na korozję elektrochemiczną
PL
W artykule przedstawiono wyniki testów odporności na korozję elektrochemiczną odlewniczego stopu magnezu AZ91. Obserwacjom poddano materiał rodzimy i złącza spawane wykonane metodą TIG (141). Jako kryterium odporności na korozję elektrochemiczną przyjęto ubytek masy i czas korozji przy określonych stężeniach roztworu kwasu H2SO4. Stwierdzono, że wzrost stężenia roztworu kwasu wpływa znacząco na szybkość korozji stopu powodując tym samym większą degradację jego powierzchni i większy ubytek masy. Zauważono również, że prędkość korozji maleje w przypadku wydłużenia czasu eksperymentu. Po czasie 72 h prędkość ta spada poniżej 0,1g/(cm2•doba), co spowodowane jest hamowaniem korozji w wyniku zobojętniania się roztworu kwasu.
EN
The article presents the results of AZ91 cast magnesium alloy resistance to electrochemical corrosion. The basic material and welding joints obtained by TIG method (141) were evaluated. The mass loss and corrosion time at specific concentrations of the H2SO4 acid solution were assumed as a criterion of resistance to electrochemical corrosion. It was found that an increase in the acid solution concentration significantly affects the rate of corrosion of alloy, thus causing a greater degradation of its surface and a higher mass loss. It was also noticed that the corrosion rate decreases when the experiment time is extended. After 72 h, this speed drops below 0.1 g/(cm2•day), which is caused by the inhibition of the corrosion as a result of the neutralization of the acid solution.
PL
Wykorzystanie stopów magnezu w przemyśle motoryzacyjnym jest utrudnione, gdyż procesy gięcia i tłoczenia muszą być prowadzone w podwyższonych temperaturach. Drugim przeciwwskazaniem jest niewielka sztywność elementów magnezowych. W pracy przedstawiono wyniki badań dynamicznego zgniatania magnezowych elementów energochłonnych. Zastosowanie elementów usztywniających w postaci pianki aluminiowej pozwala na pochłanianie dużej energii właściwej (energia podzielona przez masę). W pracy wykazano, że energia właściwa pochłaniana przez magnezowe crash-boxy może być większa niż w przypadku elementów wykonanych ze stali HC380.
EN
The use of magnesium alloys in automotive industry is difficult, because the processes of bending and pressing must be carried out at an elevated temperatures. The second contraindication is a low stiffness of magnesium elements. Following paper presents results of dynamic crushing of magnesium energy-absorbing elements. The use of aluminum foam as stiffening elements allows to absorb high specific energy (absorbed energy divided by specimen mass). The paper has shown that the specific energy absorbed by the magnesium crash-boxes is greater than specific energy absorbed by crash-boxes made of HC380 steel.
EN
In this work, the effect of the microstructure on corrosion behavior of selected Mg- and Al-based as cast alloys, was evaluated. The electrochemical examinations were carried out, and then a morphology of corrosion products formed due to local polarization on materials surface, was analyzed. It was documented that the presence of Mg2Si phase plays an important role in the corrosion course of Mg-based alloy. A selective etching was observed in sites of Mg2Si precipitates having “Chinese script”- like morphology. Analogous situation was found for Al-based alloy, where the key role was played by cathodic θ-CuAl2 phase.
EN
The results of estimation of home scrap addition in charge influence on durability and wear of casting instrumentation life in the high-pressure casting technology using the hot chamber machine of alloy of AZ91 are presented. The wear of the following elements of the casting instrumentation so-called "casting set" as: syphon, plunger, sliding-rings, nozzle and injection moulding nozzle was estimated. A wear was estimated quantitative by registering the number of mould injections for different charges to the moment of element damage supervision. A damage had to be at such level that liquidated an element from further exploitation and necessary was an exchange on new or regeneration. In a final result allowed it the detailed determination of durability of the applied rigging elements in dependence on the type of the applied type of melt. It is noticed, that together with the increase of home-scrap participation in the charge wear of pressure machine instrumentation elements increases.
EN
The effectiveness of cast iron spheroidization with FeSiMg master alloy by the traditional method and using a reaction chamber placed in the cavity of foundry mould was compared. The method of cast iron treatment in mould cavity using a reaction chamber is an innovative technology developed by the Foundry Research Institute in Krakow. The effectiveness of the spheroidization process carried out by both methods was checked on a series of test castings. The article also presents the results of metallographic examinations and mechanical testing, including the discussion of magnesium yield and its assimilation rate.
EN
The study involved using the liquid-solid compound casting process to fabricate a lightweight ZE41/AlSi12 bimetallic material. ZE41 melt heated to 660 °C was poured onto a solid AlSi12 insert placed in a steel mold. The mold with the insert inside was preheated to 300 °C. The microstructure of the bonding zone between the alloys was examined using optical microscopy and scanning electron microscopy. The chemical composition was determined through linear and point analyses with an energy-dispersive X-ray spectroscope (EDS). The bonding zone between the magnesium and aluminum alloys was about 250 μm thick. The results indicate that the microstructure of the bonding zone changes throughout its thickness. The structural constituents of the bonding zone are: a thin layer of a solid solution of Al and Zn in Mg and particles of Mg-Zn-RE intermetallic phases (adjacent to the ZE41 alloy), a eutectic region (Mg17(Al,Zn)12 intermetallic phase and a solid solution of Al and Zn in Mg), a thin region containing fine, white particles, probably Al-RE intermetallic phases, a region with Mg2Si particles distributed over the eutectic matrix, and a region with Mg2Si particles distributed over the Mg-Al intermetallic phases matrix (adjacent to the AlSi12 alloy). The microstructural analysis performed in the length direction reveals that, for the process parameters tested, the bonding zone forming between the alloys was continuous. Low porosity was observed locally near the ZE41 alloy. The shear strength of the AZ91/AlSi17 joint varied from 51.3 to 56.1 MPa.
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