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1
Content available remote Fastener materials after high-pressure forming
EN
This paper presents general characteristics of high-pressure forming of metals and metal alloys with the use of hydrostatic extrusion method. It describes the advantages of the process with particular attention paid to the possibility of refining the structure of metals and metal alloys to a nanometric or ultra-fine level resulting in significant improvement of their mechanical properties. It shows the examples of practical application of formed metals, namely titanium and aluminium alloy AA5083, in the manufacture of fastening elements.
EN
Friction welding is one of the most economical process of joining solid-state materials. This technique allows to weld similar and dissimilar materials in a very short time. Friction welding of metal with composites gives new possibilities of application, due to the fact that materials have different physical and mechanical properties. In the study, aluminum alloy 44200 was friction welded to Al/Al2O3 composite. In addition, the following inspections were performed: optical microscopy, microhardness measurements and also tensile strength for all joints produced by friction welding. All of the studies were performed to evaluate the quality of connection between the 44200 alloy and the composites on the aluminum alloy matrix reinforced with ceramic phase of Al/Al2O3.
PL
Zgrzewanie tarciowe to jedna z bardziej ekonomicznych metod trwałego łączenia materiałów w stanie stałym. Metoda ta umożliwia wykonywanie złączy zarówno jednoimiennych, jak i różnoimiennych w bardzo krótkim czasie. Zaletą zgrzewania tarciowego jest możliwość uzyskania złączy o wysokiej jakości. Zgrzewanie tarciowe kompozytów z metalami, stwarza nowe możliwości aplikacji, z uwagi na fakt, że oba materiały posiadają różne właściwości fizyczne oraz mechaniczne. W pracy przeprowadzono próby spajania stopu aluminium EN-AC-44200 z kompozytami Al/Al2O3. W opracowaniu przeprowadzono następujące badania złączy stop aluminium-kompozyt uzyskanych metodą zgrzewania tarciowego: mikroskopowe, twardości, mechaniczne (pomiar wytrzymałości na rozciąganie). Wykonane badania miały na celu ocenę jakości połączenia pomiędzy stopem 44200, a kompozytami na osnowie stopu aluminium wzmacnianymi fazą ceramiczną Al/Al2O3.
EN
This paper presents research regarding refill friction stir spot welding (RFSSW) of EN AW-7075-T6 Alclad aluminium alloy sheets, and the joint behaviour under static and dynamic loads. Single-point lap joint of sheets with different thicknesses, which corresponds to those used in aircraft fuselage structures, i.e. upper sheets with a thickness of 1.6 mm and lower sheets with a thickness of 0.8 mm, were analysed regarding the failure mechanism in static shear testing. It has been shown that a properly made joint is destroyed as a result of tension in the lower plate. The lower plate at the edge of the weld is structurally weakened by the HAZ, but also geometrically due to plastic deformation during the welding process, which has been demonstrated by metallographic investigations as well as by the FEM numerical model. Single-row RFSSW welded joints with different spacing of the welds and a riveted joint were impact tested. It has been shown that welded joints are characterized by a greater stiffness, which is higher when the spacing of the welds is smaller.
PL
Praca przedstawia badania połączenia zakładkowego RFSSW blach ze stopu aluminium EN AW-7075-T6 Alclad pod wpływem obciążeń statycznych oraz dynamicznych. Jednopunktowe połączenie zakładkowe blach o różnej grubości co odpowiada połączeniom stosowanym w konstrukcjach kadłubów lotniczych tj. górna blacha o grubości 1.6 mm oraz dolna blacha o grubości 0.8 mm, poddano analizie mechanizmu zniszczenia w próbie statycznego ścinania. Wykazano, że poprawnie wykonane połączenie ulega zniszczeniu na skutek rozciągania dolnej blachy. Dolna blacha przy krawędzi zgrzeiny jest osłabiona strukturalnie przez strefę wpływu ciepła, ale także geometrycznie poprzez deformację plastyczną powstałą podczas procesu zgrzewania, co wykazano na podstawie badań metalograficznych jak również przy użyciu modelu numerycznego MES. Jednorzędowe połączenia zakładkowe poddano badaniom udarności. Badano połączenia zgrzewane RFSSW o różnym rozstawie zgrzein oraz połączenie nitowane. Wykazano, że połączenia zgrzewane charakteryzują się większą sztywnością, która jest tym większa im mniejszy rozstaw zgrzein.
EN
The use of cast aluminium has still increased, so have the mechanical property requirements. By casting and also in other metallurgical processes, the inclusions enter to the molten aluminium alloy and it exhibits poor ductility or toughness. It can cause a variety of problems in the manufacture of aluminium alloy castings. Therefore, the purification of the molten aluminium alloy is one of the most important processes for improving the quality of Al-products. Filters have been used for many years in order to improve the quality of castings. The inclusions in molten secondary AlSi7Mg0.3 cast were removed using depth filtration by ceramic foam filters of 20 ppi porosity. Were used 4 types of ceramic filters in 2 thicknesses (15 and 22 mm); Brinell hardness and porosity were measured. Quality of microstructure (occurrence of oxidic particles and larger non-metallic inclusions) was observed. Experimental results show that the insertion of ceramic filters into the inlet system has contributed primarily to a decrease in porosity. On the microstructure, the inclusion of filters was not significantly reflected.
EN
Ultrasonic treatment is known to be efficient for aluminium melt degassing with the additional benefits of being both economical and environment friendly. This paper describes the effect of ultrasonic degassing on the preparation of an AlSi9Cu3(Fe) alloy for High Pressure Die Casting (HPDC). The degassing efficiency was assessed in terms of the indirect evaluation of the melt, by means of the reduced pressure test and the porosity evaluation of the cast parts. Additionally, the corresponding hydrogen content was estimated with an experimental equation reported in the literature. Ultrasonic degassing shows greater efficiency in terms of hydrogen removal from the melt than conventional N2 + Ar lance bubbling. Components produced by HPDC without degassing, with ultrasonic degassing and with lance degassing, were analysed by computed tomography and by metallography. The results show that the components produced by HPDC after ultrasonic degassing have a similar porosity level to components degassed with conventional lance bubbling, both showing an important improvement over components produced without degassing treatment. Hardness values were similar for all different treatment conditions and well over the minimum value established for the alloy by the corresponding standard.
EN
Wear resistance, which is one of the main technological quality features of machine parts and tools, is determined by the properties of their surface layer. The demand for high-quality products forces manufacturers to use modern structural and tooling materials as well as efficient and cost-effective methods of their treatment. The paper presents the results of research on selected properties of tools made of tool steels and sintered carbides, as well as parts made of aluminum alloy subjected to selected surface treatment processes, such as mechanical (grinding, turning, milling, burnishing) and thermo-chemical (nitriding, sulfonitriding) processes, and physical vapor deposition (PVD) of coatings. The presented results, including analyses of the surface geometric structure, microstructure, and microhardness, as well as tribological and machining properties of selected materials, indicate the possibility of improving the functional quality of tools and machine parts.
EN
The article presents research aimed at determining the effect of adding rare earth elements to near-eutectic Al-Si and Al-Si-Ni alloys on the microstructure and mechanical properties of the obtained products. Material for the research was prepared using a melt spinner - a device used for rapid crystallization, casting thin ribbons, which were then subjected in subsequent stages to fragmentation, consolidation and plastic working. The ribbons and extruded rods cast were described in terms of their structure and their strength properties were determined at different measurement temperatures. It was shown that the lightweight materials produced from aluminium alloys using the rapid solidification process have an ultra-fine structure and good strength properties. Analysis under a microscope confirmed that the addition of rare earth alloys Al-Si and Al-Si-Ni causes fragmentation of the microstructure in the tapes produced. The presence of rare earth elements in the alloys tested has an impact on the type and the morphology of the particles of the microstructure’s individual components. In addition to the change in particle morphology, the phenomenon of the separation of numerous nanometric particles of intermetallic phases containing rare earth elements was also observed. The change in microstructure caused by the addition of rare earth elements in the form of a mischmetal increases the mechanical properties.
EN
Purpose: The aim of the proposed research is to investigate the influence of temperature and duration of isothermal melt processing on structural characteristics of castings in connection with technological background of charge metal. Design/methodology/approach: Ferrous and non-ferrous alloys were obtained by remelting a charge with a dispersion-structured structure (which was ensured by high- speed crystallization). Remelting was carried out at different temperatures of overheating of the melt over the liquidus with different isothermal exposure at these temperatures. Experimental castings were crystallized under normal conditions. It was studied a change of structure formation and mechanical characteristics depending on the temperature and duration of thermal treatment of the melt before crystallization. Findings: It is established that isothermal treatment of the melt at the overheating of the liquid metal above a certain equilibrium temperature of the micro-inhomogeneous melt (Te) causes a gradual loss of hereditary characteristics of the original charge metal, increase of the chemical homogeneity of the melt and the formation of crystallization and formation a corresponding change in the mechanical properties of castings. Research limitations/implications: The results can be complemented by studies of the effect of thermal treatment in the temperature range of crystallization. Practical implications: The results can be used to select the optimal heat treatment during remelting and, accordingly, the mechanical properties of the resulting casting. Originality/value: The obtained results testify to the predominant influence of temperature on the dispersion of the cast structure of steels, given the duration of technological operations of preparation and casting of steels in the manufacture of castings in industrial conditions.
EN
The paper deals with the effect of heating of various prepared batch materials into semisolid state with subsequent solidification of the cast under pressure. The investigated material was a subeutectic aluminium alloy AlSi7Mg0.3. The heating temperature to the semisolid was chosen at 50% liquid phase. The used material was prepared in a variety of ways: heat treatment, inoculation and by squeeze casting. Also the influence of the initial state of material on inheritance of mechanical properties and microstructure was observed. The pressure was 100 MPa. Effect on the resulting casting structure, alpha phase distribution and eutectic silicon was observed. By using semisolid squeeze casting process the mechanical properties and microstructures of the casts has changed. The final microstructure of the casts is very similar to the microstructure that can be reached by technology of thixocasting. The mechanical properties by using semisolid squeeze casting has been increased except the heat treated material.
EN
Refill friction stir spot welding (RFSSW) is a solid state joining technology that has the potential to replace processes such as the open-air fusion bonding technique and rivet technology in aerospace applications. Selection of proper RFSSW parameters is a crucial task which is important to ensure the mechanical strength of the joint. The aim of this paper is to undertake numerical modelling of the RFSSW process to understand the physics of the welding process, which involves large deformations, complex contact conditions and steep temperature gradients. Three-dimensional fully coupled thermo-mechanical models of RFSSW joints between Alclad 7075-T6 aluminium alloy sheets have been built in the finite-element-based program Simufact Forming. The simulation results included the temperature distribution and the stress and strain distributions in the overlap joint. The results of numerical computations have been compared with experimental ones. The numerical model was able to predict the mechanics of material flow during the joining of sheets of Alclad aluminium alloys using RFSSW. The predictions of the temperature gradient in the weld zone were in good agreement with the temperature measured experimentally. The numerical models that have been built are capable of simulating RFSSW to reduce the number of experiments required to set optimal welding parameters.
EN
This paper deals with different types of artificial ageing and its effect upon the mechanical properties of an aluminium alloy. For the purposes of this research, the EN AW 2017 alloy was subjected to different types of heat treatment. These samples were subjected to different analyses. The results of hardness measurements (HB and HV) revealed the highest values of the non‑heat treated sample. The static tensile stress test proved the highest ductility of the heat treated samples. Overall, the best were revealed for the sample artificially aged at 160°C.
EN
In the process of plastic bending of thin-walled profiles, there is a significant deformation of the cross-section, which has a very significant impact on the course and effects of the shaping process construction products. In this paper, the experimental, analytical as well as numerical analyses of the box profile bending process enabled to establish the relationships determining the dependence of the cross-sectional form and bending moment on the bending curvature. The following paper discusses pure bending moment and the cross-sectional deformation of 21.5×21.5×1.8 mm and 25×25×2.5 mm square tubes made of the 6060 aluminium alloy. Satisfactory agreement of the experimental results and numerical calculations was obtained for the values of horizontal and vertical wall deflection, as well as for the experimental, calculated and numerical bending moment characteristics.
13
Content available remote Gazy osłonowe do spawania łukowego aluminium i jego stopów
PL
W artykule omówiono rodzaj i skład gazów używanych podczas spawania aluminium i jego stopów z zastosowaniem metod: TIG, MIG i LBW, jak również opisano wpływ tych gazów na proces spawania i jakość złączy spawanych.
EN
The type and composition of gases used in TIG, MIG and LBW welding of aluminium and its alloys are discussed, as well as the influence of shielding gases on the welding process and the quality of welded joints are described.
EN
Explosion welding of cooper C10200 to AW 5083 aluminium alloy was performed. The C10200 was proposed as a flyer plate. A parallel setup was used during explosive welding. Bimetals were characterized by regular wavy interface. The intermetallic compound (IMC) layer was observed at the interface of bimetals after 12 month, however, no annealing was performed. EDX analyses revealed that the interface layer consists of the intermetallic compound CuAl. Microhardness at the interface increased due to the presence of the IMC and work hardening as well.
PL
Przedstawiono wyniki zgrzewania wybuchowego miedzi C10200 ze stopem aluminiowym AW 5083. Płytka wykonana z miedzi C10200 była elementem napędzanym. Zgrzewanie wybuchowe prowadzono równolegle na dwóch stanowiskach. Otrzymane bimetale charakteryzowały się regularną falistą powierzchnią łączenia. Badania warstwy związku międzymetalicznego, w obszarze połączenia bimetalicznego, przeprowadzono po upływie 12 miesięcy, jednakże bez wyżarzania. Analiza EDX wykazała, że warstwa łącząca składa się z związku międzymetalicznego CuAl. Mikrotwardość w obszarze łączenie wzrasta zarówno w wyniku obecności związku międzymetalicznego, jak i przeprowadzonego zgrzewania.
EN
Electron beam welding, called electron welding consists in penetrating the elements being welded with heat obtained from the elements’ bombardment in vacuum with concentrated electron beam of high energy. Concentration of the electron beam of high kinetic energy in a very small space results in generating the heat of high concentration causing melting of material in high depth. During the metal melting the electron beam makes a narrow weld of little heat affected zone (HAZ). This paper presents the test results on selection of parameters of electron beam welding of 12 mm thickness sheets of AlMg3 aluminum alloy. The beam electron melting through was carried out in vacuum by means of the welding machine WS-15 KW/100 KV. Before melting, the sheets were degreased in tetrachloroethylene and oxides were removed with 15% solution Na2Co3. The influence of electron beam melting through of sheets on their mechanical properties was tested as well as resistance to stress corrosion cracking and resistance to corrosion in fast seawater flow (10 m/s). The slow strain rate stress corrosion tests in the air and artificial seawater were performed. It was found that electron beam melting through of the AlMg3 alloy does not decrease the mechanical properties in comparison to the native material. The crack during the static tension test had ductile character and proceeded in the native material. AlMg3 alloy melting with electron beam shows a very good stress corrosion resistance.
EN
The article presents the impact of welding imperfections on the strength and microhardness of AW 5754 aluminium alloy welded joints executed with the TIG method. It presents the results of tomographic tests of welds. The results of strength and microhardness tests involving welds executed under various welding process parameters were shown. The impact of welding imperfections on the strength and microhardness of a welded joint was analysed. Based on analysing the relations between the r Pearson coefficient values and multiple correlation, significant relationships between strength, hardness and weld defects were evidenced. Furthermore, a very strong relation between the welding process parameters, welding imperfections, and weld strength and microhardness was shown.
PL
W artykule przedstawiono wpływ niezgodności spawalniczych na wytrzymałość i mikrotwardość połączeń spawanych ze stopu aluminium AW 5754 wykonanych metodą TIG. Zaprezentowano wyniki badań tomograficznych spawów, badań wytrzymałościowych oraz mikrotwardości spawów wykonanych przy różnych parametrach procesu spawania. Dokonano analizy wpływu niezgodności spawalniczych na wytrzymałość oraz mikrotwardość połączenia spawanego. Wykazano istotne zależności pomiędzy wytrzymałością, twardością a niezgodnościami w spawach. Ponadto wykazano silny związek pomiędzy parametrami procesu spawania, niezgodnościami spawalniczymi, wytrzymałością i mikrotwardością spawów.
EN
The paper deals with the fabrication of the surface layer enriched with Zn on AlSi17 aluminium alloy to modify the microstructure and surface properties of the alloy. The continuous surface layer was fabricated on the AlSi17 substrate by the hot-dip galvanizing of AlSi17 for 15min in a Zn bath heated to 450°C. The thickness of the layer was about 100 μm. The layer was characterised by a multi-component microstructure containing the regions of a solid solution of Al in Zn and dendrites of a eutectoid composed of a solid solution of Al in Zn and a solid solution of Zn in Al. In the layer, fine particles of Si with a regular shape were distributed. The results indicated that these Si particles formed by the action of Zn on the eutectic Si precipitations in the AlSi17 substrate. In the microstructure, large primary Si crystals and multi-phase precipitations, originating from the substrate, were also observed. The surface layer had much higher microhardness than the AlSi17 substrate. The results showed that hot-dip galvanizing can be used to modify the microstructure and properties of the surface layer of AlSi17. The study indicates the possibility of conducting further research on the fabrication of joints between AlSi17 and other metallic materials using a Zn interlayer fabricated by hot-dip galvanizing.
PL
Ewolucja zintegrowanego projektowania procesów i konstrukcji inżynierskich, ze szczególnym uwzględnieniem zaawansowanego modelowania numerycznego i symulacji komputerowych, pozwala znacznie skrócić cykl wdrażania innowacyjnych rozwiązań materiałowych, technologicznych czy użytkowych, mających kluczowe znaczenie w projektach realizowanych w przemyśle lotniczym, energetycznym czy motoryzacyjnym. Wykorzystanie zintegrowanego procesu projektowania materiałów i konstrukcji (ang. ICME – Integrated Computational Materials Engineering) pozwoliło na określenie najnowszych tendencji stosowania procesu oraz wstępne prześledzenie możliwości integracji metodyki w procesie projektowania ultralekkiej, wysokowytrzymałej konstrukcji odlewanej na przykładzie odlewu dźwigni pedału hamulca. Przeprowadzone badania dotyczyły zagadnień projektowych zmierzających do modyfikacji kształtu konstrukcji odlewanej z wykorzystaniem wzajemnych relacji na drodze badań materiałowych, procesów modelowania oraz prób doświadczalnych.
EN
The evolution of the integrated design of engineering processes and structures, including in particular advanced numerical modelling and computer simulations, has enabled a significant shortening of the implementation cycle of innovative material, technological and utility solutions that are essential in projects pursued in the aviation, power and automotive industries. The use of Integrated Computational Materials Engineering (ICME) has allowed the determination of the latest trends in the use of the process, and the initial identification of the integration methods in the design process of ultra-light, high-strength cast structures using the example of a brake pedal lever casting. The research concerned design issues aimed at modifying the shape of the cast structure using interrelationships through material testing, modelling processes and experimental tests.
EN
The paper deals with squeeze casting technology. For this research a direct squeeze casting method has been chosen. As an experimental material, the AlSi12 and AlSi7Mg0.3 alloys were used. The influence of process parameters variation (pouring temperature, mold temperature) on mechanical properties and structure will be observed. For the AlSi7Mg0.3 alloy, a pressure of 30 MPa was used and for the AlSi12 alloy 50 MPa. The thicknesses of the individual walls were selected based on the use of preferred numbers and series of preferred numbers (STN ISO 17) with the sequence of 3.15 mm, 4 mm, 5 mm, 6.3 mm and 8 mm. The width of each wall was 22 mm and length 100 mm. The mechanical properties (Rm, A5) for individual casting parameters and their individual areas of different thicknesses were evaluated. For the AlSi7Mg0.3 alloy, the percentage increase of the tensile strength was up to 37% and the elongation by 400% (at the 8 mm thickness of the casting). For the AlSi12 alloy, the strength increased from 8 to 20% and the tensile strength increased from 5 to 85%. The minimum thickness of the wall to influence the casting properties by pressure was set to 5 mm (based on the used casting parameters). Due to the effect of the pressure during crystallization, a considerable refinement and uniformity of the casting structure occured, also a reduction in the size of the eutectic silicate-eliminated needles was observed.
EN
This paper reports on the results of strength tests of single-lap joints used in the aerospace industry with “Hi-Lok” fastener. The samples subjected to testing were made of EN-AW 2024 aluminium alloy and carbon composite. A part of the samples was additionally sealed with the use of Naftoseal MC-780 Class C sealant. The application of the MC-780 Class C sealant boosts the strength of a single lap joint of EN-AW 2024 T3 Al alloy and carbon composite. The strength test results were complemented with the analysis of selected 2D and 3D surface roughness parameters, and isometric images of the analysed surfaces. Additional information on the specimen surface quality was provided with photographic images taken with Keyence VHX-5000 microscope at x300 magnification. In the conclusion section of this paper, the study is summarised and its key findings are listed.
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