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The role of stirring time on the metallurgical and mechanical properties during modified friction stir clinching of AA6061-T6 and AA7075-T6 sheetsMemon, S., Paidar, M., Ojo, O.O., Cooke, Kavian O., Babaei, B., Masoumnezhad, M. 25 November 2020 (has links)
Yes / In this study, the modified friction stir clinching process was successfully utilized to weld the AA7075-T6 to AA6061-T6 aluminum alloys. The approach of this study was to appraise the influence of the stirring time (6, 12, and 18 s) on the metallurgical and mechanical behavior of the welded samples. The microstructural study demonstrated that stirring time significantly affected joint properties and material flow, which can be ascribed to the discrepancy in the properties of the Al alloys used in this study. Void, local melting and defect-free joints were produced under the stirring times of 6 s, 18 s, and 12 s respectively. It was found that tensile/shear strength increased significantly from 63.5 MPa to 109 MPa as the stirring time increased from 6 s to 12 s, while a further increase in the stirring time to 18 s significantly decreased the joint's strength to 76.1 MPa. The observed failed samples showed that stirring time did not influence fracture mode.
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Cyclic Polarization of AA 3102 in Corrosive Electrolytes Containing Sodium Chloride and Ammonium SulfateDorreyatim, Mohammad 12 1900 (has links)
Corrosion of all aluminum microchannel heat exchangers present a challenge in automotive and heating, ventilation, and air conditioning (HVAC) industries. Reproducibility of Salt Water Acetic Acid Test (SWAAT) has been questioned and a need to new corrosion tests with better reproducibility has risen. Cyclic polarization, that is an electrochemical test, was explored for its suitability for the assessment of AA 3102 tube material that is currently a popular aluminum alloy used in manufacturing of heat exchanger.
Corrosive electrolytes containing 3.5 % sodium chloride with 0.5 % ammonium sulfate (high chloride) or 0.5 % sodium chloride with 3.5 % ammonium sulfate (high sulfate) at their pH or acidic (pH=4) were used to measure corrosion potential (Ecorr), protection potential (Epp), pitting potential (Epit), Tafel constants (βa and βc), corrosion rate (mpy). Corrosive electrolyte used in SWAAT test (4.2% Sea Salt at pH 2.9) was also used to compare corrosion resistance of AA 3102 in SWAAT electrolyte compared to the other electrolytes used in this research. Scanning electron microscopy (SEM) was used to observe and document sample surface corrosion damage after each electrochemical test on all samples.
Results of the cyclic polarization tests indicated that SWAAT electrolytes was the most aggressive electrolyte resulting in highest corrosion rates compared to all other electrolytes used in this investigation. SEM results indicated AA 3102 alloy exhibited higher pitting tendency in electrolytes with high sodium chloride whereas high sulfate electrolytes cause appearance of uniform corrosion surface damage on this alloy. Both high sulfate and SWAAT electrolytes showed intergranular corrosion but high chloride electrolyte showed severe pitting of AA 3102.
Mohammad Navid Dorreyatim- Cyclic Polarization of AA 3102 in Corrosive Electrolytes Containing Sodium Chloride and Ammonium Sulfate. Master of Science (Mechanical and Energy Engineering), December 2016, 98 pp., references, 31 titles.
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Efeito do jateamento com granalhas de aço na tensão residual e no comportamento mecânico da liga de alumínio 6082 / Effect of shot peening on residual stress and mechanical behavior of aluminum alloy 6082Borges, Arnaldo Augusto Ciquielo 13 December 2017 (has links)
A liga de alumínio 6082 apresenta de média para alta resistência mecânica e é de grande importância no mercado de perfis extrudados. O processo de jateamento com granalha de aço em componentes automotivos e aeronáuticos, visando induzir uma condição otimizada de tensão residual de compressão na superfície, tem se mostrado eficaz na melhoria das propriedades mecânicas em fadiga desses componentes. Neste sentido, este trabalho tem como objetivo estudar os efeitos do jateamento com granalhas de aço na tensão residual e no comportamento mecânico em fadiga da liga de alumínio 6082 solubilizada e envelhecida artificialmente. Inicialmente foram feitos tratamentos térmicos de solubilização e envelhecimento artificial visando a determinação da melhor condição em termos de resistência mecânica da liga de alumínio 6082. A seguir foram realizados experimentos com diversos tipos de granalhas esféricas de aço e em condições variadas de jateamento (velocidade de rotação e tempo), definindo-se a melhor condição de tensão residual medida por difração de raios x. Ensaios de fadiga em corpos de prova jateados com granalha de aço na melhor condição de tensão residual foram executados em máquina flexo-rotativa e comparados com os resultados do material sem jateamento. A melhor condição de tensão residual ocorreu em decorrência do jateamento com o uso da granalha de aço S170PEE, rotação da turbina à 2500 rpm e tempo de exposição de 1 minuto. A curva de tensão residual em profundidade para a condição escolhida apresentou resultados coerentes somente até 76 μm devido à presença de grãos grandes em profundidades superiores a esta. As curvas S-N mostraram que houve um ganho na vida em fadiga em tensões elevadas e baixo número de ciclos para romper devido jateamento com granalha de aço. Ao contrário, ocorreu um efeito deletério na vida em fadiga em tensões baixas e número de ciclos elevados para romper, devido à influência do aumento da rugosidade em ensaios de fadiga mais longos. / Aluminum alloy 6082 exhibits medium to high strength and is widely used as extruded products. Shot peening of automobile and aircraft components, carried out to induce optimum residual compressive stress on the surface, improves fatigue properties of these components. In this context, the aim of this investigation was to study the effects of shot peening on the residual stress and fatigue behavior of solution treated and artificially aged 6082 aluminum alloy. Initially, solution treatment and artificial ageing of this alloy were carried out to determine the best conditions in terms of alloy strength. Subsequently, experiments were carried out with different types of spherical steel shots, under a variety of peening conditions (rotation speed and duration), to define the best set of conditions to increase residual stress that was measured using x-ray diffraction. Fatigue tests were carried out using a rotating-bending machine on shot peened specimens that had the highest residual stress. These results were compared with those of specimens that were not shot peened. The highest residual stress was observed when peening was done with S170PEE steel shots, at 2500 rpm for 1 minute. The variation in residual stress as a function of depth, for the above-mentioned peening conditions, was coherent only up to a depth of 76 μm and attributable to the presence of large grains at depths higher than this. The S-N curves revealed an increase in fatigue life at high stresses and at low cycles to failure and attributed to shot peening. Contrary to this, a deleterious effect in terms of reduction in fatigue life was observed at low stresses and at high cycles to failure, due to increase in surface roughness of the specimens during the extended fatigue tests.
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Estudos da proteção à corrosão da liga de alumínio AA7075-T6 por revestimentos a base de polianilina / Corrosion protection of the aluminum alloy AA7075-T6 by coatings based on polyanilineBandeira, Rafael Marinho 14 July 2017 (has links)
Neste trabalho foram formados, sobre uma superfície de liga de alumínio AA7075-T6, revestimentos de polianilina (PANI) e da blenda polianilina/policloreto de vinila na proporção massa-massa de 1/1 (PANI/PVC 1/1), com diferentes espessuras. Os revestimentos foram avaliados quanto as suas habilidades na proteção da corrosão da liga de alumínio. Utilizou-se uma solução de NaCl 3,5%, como solução corrosiva em todos os ensaios de corrosão. A espessura dos revestimentos de PANI foi variada de 5 a 35 µm e estudou-se a relação entre espessura, rugosidade e hidrofobicidade e a proteção por estes revestimentos. Os revestimentos com espessuras de 12 a 23 µm apresentaram menor rugosidade, maior ângulo de contato e melhor proteção da corrosão verificada por medidas eletroquímicas, tais como espectroscopia de impedância eletroquímica e polarização linear. As imagens obtidas por microscopia eletrônica de varredura mostraram que os revestimentos de PANI são homogêneos e que não exibiam defeitos decorrentes da exposição no ambiente corrosivo. Já a blenda, apresentou um desempenho maior na proteção da corrosão quando comparado com a PANI pura. Medidas de espectroscopia de impedância eletroquímica e de polarização linear mostraram que a blenda possui alta resistência de polarização, com potenciais de corrosão estáveis e deslocados à região anódica para os eletrodos com revestimentos de maior espessura (26,3 ± 0,9 µm). Imagens obtidas por microscopia eletrônica de varredura e de força atômica, juntamente com a análise de composição por espectroscopia de energia dispersiva de raios-X (EDX) contribuíram para entender a maior eficiência de proteção promovida pela blenda. / In this study, an aluminum alloy (AA7075-T6) was coated with polyaniline (PANI) and polyaniline/polyvinyl chloride (PANI/PVC in 1:1 ratio by mass) blend coatings of different thickness. These coatings were evaluated for their ability to protect the aluminum alloy against corrosion. For studying the corrosion of aluminum alloy in saline environment, a 3.5% NaCl solution was used in all the corrosion tests. The thickness of PANI-based films was varied between 5 to 35 µm and the effect of film thickness, roughness and hydrophobicity on the corrosion protection properties of the coatings was evaluated. The coatings with thickness between 12 and 23 µm exhibited lower roughness, higher contact angles and better corrosion protection as confirmed by electrochemical measurements such as electrochemical impedance spectroscopy and linear polarization. Morphological analysis by scanning electron microscopy confirmed that the PANI coatings are homogeneous and present almost no defects upon exposure to the corrosive environment. Compared to pure PANI coatings, the coatings consisting of PANI/PVC blend presented better performance against corrosion. Electrochemical impedance spectroscopy and linear polarization measurements showed that the blends have high polarization resistance with stable corrosion potentials that are shifted to the anodic region for the electrodes with thicker coatings (26.3 ± 0.9 µm). Surface analysis by scanning electron microscopy, atomic force microscopy and elemental analysis by energy-dispersive X-ray spectroscopy were used to gather information that helped understanding the better corrosion resistance of PANI/PVC coatings.
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A metalurgia do pó para produção de peças de alumínio na indústria metalúrgicaSantos, Marcus Aurélio dos January 2018 (has links)
O objetivo desse trabalho é analisar a fabricação de buchas a base de Alumínio empregando o processo de Metalurgia do Pó, em substituição ao processo atual de fundição e usinagem. O material testado é uma liga a base de Alumínio AlSi10Cu3, essa liga contem 87% de Alumínio, 10% de Silício, 2,5% de Cobre, 0,25% de Magnésio e Manganês, conforme a norma DIN EN 1706. As amostras foram compactadas à 600MPa, resultado obtido da curva de compressibilidade. As amostras foram sinterizadas a uma temperatura de 550ºC durante 60 minutos. Após sinterização as amostras foram submetidas ao processo de Tratamento Térmico T6, com temperatura de solubilização de 480°C por 5 horas e envelhecimento a 220°C por 5 horas, nomeado Tratamento Térmico A. Foram realizados ensaios de densidade, dureza, metalografia, compressibilidade, difração de raios-x e variação dimensional. A densidade das amostras sinterizadas atingiram 2,52 g/cm3 ± 0,25. A dureza superficial das amostras atingiram uma média de 51 HB ± 4. Com o tratamento térmico T6 a dureza elevou-se para 74 HB ± 2. A variação dimensional das amostras após sinterização foi de 0,20% na área dos corpos de prova. Foram estudadas também diferentes composições químicas para elevar a dureza superficial. Executou-se um teste com outros parâmetros de Tratamento Térmico T6 para aumento da dureza, chamado de Tratamento Térmico B, com parâmetros de temperatura de solubilização de 550°C por 1 hora e envelhecimento com 160°C por 18 horas. / The objective of this work is to analyze the manufacture of aluminum based bushings employing the Powder Metallurgy process in substitution of the current process of casting and machining. The material tested is an AlSi10Cu3 aluminum alloy, this alloy contains 87% aluminum, 10% silicon, 2.5% copper, 0.25% magnesium and manganese, according to DIN EN 1706. The samples were pressed at 600MPa, result obtained from the compressibility curve. The samples were sintered at a temperature of 550°C for 60 minutes. After sintering, the samples were submitted to the T6 Thermal Treatment process, with a solubilization temperature of 480°C for 5 hours and aging at 220°C for 5 hours, named Thermal Treatment A. Density, hardness, metallography, compressibility, X-ray diffraction and dimensional variation testings were performed. The density of the sintered samples reached 2.52 g/cm3 ± 0.25. The surface hardness of the samples reached the mean of 51 HB ± 4. With the heat treatment T6 the hardness increased to 74 HB ± 2. The dimensional variation of the samples after sintering was 0.20% by area. Different chemical compositions were also studied to raise the surface hardness. A test was performed with other parameters of T6 Thermal Treatment to increase the hardness, called Thermal Treatment B, with parameters of solubilization temperature of 550°C for 1 hour and aging with 160°C for 18 hours.
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Experimental study of oxidation, ignition and combustion of aluminum based nanomaterialsFahad, Noor January 2014 (has links)
Aluminum based reactive nanomaterials have extensive applications in many fields including solid propellants, pyrotechnics, and catalytic reactions. One recent example is the novel concept of using nanostructured energetic particles for energy storage where the controlled exothermic reaction is the key to control the energy release process. It is of primary interest to understand the thermodynamics, kinetics, morphological and structural properties of these particles during the exothermic reaction. While the physiochemical properties of the monometallic powders are determined only by their size, the properties of bimetallic nanoalloys can be also engineered by their constituent compositions. This thesis conducts a systematic experimental investigation of the oxidation, ignition, and combustion of nano aluminum particles (nAl) and nanoalloys such as nanoscale aluminium-copper (n-AlCu) and aluminium-zinc (n-AlZn). The oxidation experiments are conducted by a TGA/DSC system with detailed characterisation of particles before and after the experiments by scanning electron microscopy (SEM), transmission electron microscopy (TEM), the Nanosizer, Brunauer–Emmett–Teller (BET), energy dispersive X-ray spectroscopy (EDS) and powder X-ray diffractionmetry (XRD). In the TGA/DSC analysis, nanomaterials are oxidized either at constant temperature or under different heating rates in the controlled atmosphere of air or nitrogen. A unique early ignition reaction is observed at the high heating rates for nAl and n-AlCu, which is associated with the effect of polymorphic phase transformation of the alumina shell and the early melting of the aluminum core. Different to the conventional shrink-core concept, hollow structures, i.e. nanoholes, in the central regions of nAl are observed and a phenomenal model is proposed. The comparison of the thermal-chemical characteristics of different nanomaterials reveals some unique 5 features related to nano-alloys such as increased reactivity. A preliminary combustion experiment on feeding nanoparticles in a methane stream is performed with a Bunsen burner setup, where the burning characteristics of different nanoparticles are analysed.
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Efeito do jateamento com granalhas de aço na tensão residual e no comportamento mecânico da liga de alumínio 6082 / Effect of shot peening on residual stress and mechanical behavior of aluminum alloy 6082Arnaldo Augusto Ciquielo Borges 13 December 2017 (has links)
A liga de alumínio 6082 apresenta de média para alta resistência mecânica e é de grande importância no mercado de perfis extrudados. O processo de jateamento com granalha de aço em componentes automotivos e aeronáuticos, visando induzir uma condição otimizada de tensão residual de compressão na superfície, tem se mostrado eficaz na melhoria das propriedades mecânicas em fadiga desses componentes. Neste sentido, este trabalho tem como objetivo estudar os efeitos do jateamento com granalhas de aço na tensão residual e no comportamento mecânico em fadiga da liga de alumínio 6082 solubilizada e envelhecida artificialmente. Inicialmente foram feitos tratamentos térmicos de solubilização e envelhecimento artificial visando a determinação da melhor condição em termos de resistência mecânica da liga de alumínio 6082. A seguir foram realizados experimentos com diversos tipos de granalhas esféricas de aço e em condições variadas de jateamento (velocidade de rotação e tempo), definindo-se a melhor condição de tensão residual medida por difração de raios x. Ensaios de fadiga em corpos de prova jateados com granalha de aço na melhor condição de tensão residual foram executados em máquina flexo-rotativa e comparados com os resultados do material sem jateamento. A melhor condição de tensão residual ocorreu em decorrência do jateamento com o uso da granalha de aço S170PEE, rotação da turbina à 2500 rpm e tempo de exposição de 1 minuto. A curva de tensão residual em profundidade para a condição escolhida apresentou resultados coerentes somente até 76 μm devido à presença de grãos grandes em profundidades superiores a esta. As curvas S-N mostraram que houve um ganho na vida em fadiga em tensões elevadas e baixo número de ciclos para romper devido jateamento com granalha de aço. Ao contrário, ocorreu um efeito deletério na vida em fadiga em tensões baixas e número de ciclos elevados para romper, devido à influência do aumento da rugosidade em ensaios de fadiga mais longos. / Aluminum alloy 6082 exhibits medium to high strength and is widely used as extruded products. Shot peening of automobile and aircraft components, carried out to induce optimum residual compressive stress on the surface, improves fatigue properties of these components. In this context, the aim of this investigation was to study the effects of shot peening on the residual stress and fatigue behavior of solution treated and artificially aged 6082 aluminum alloy. Initially, solution treatment and artificial ageing of this alloy were carried out to determine the best conditions in terms of alloy strength. Subsequently, experiments were carried out with different types of spherical steel shots, under a variety of peening conditions (rotation speed and duration), to define the best set of conditions to increase residual stress that was measured using x-ray diffraction. Fatigue tests were carried out using a rotating-bending machine on shot peened specimens that had the highest residual stress. These results were compared with those of specimens that were not shot peened. The highest residual stress was observed when peening was done with S170PEE steel shots, at 2500 rpm for 1 minute. The variation in residual stress as a function of depth, for the above-mentioned peening conditions, was coherent only up to a depth of 76 μm and attributable to the presence of large grains at depths higher than this. The S-N curves revealed an increase in fatigue life at high stresses and at low cycles to failure and attributed to shot peening. Contrary to this, a deleterious effect in terms of reduction in fatigue life was observed at low stresses and at high cycles to failure, due to increase in surface roughness of the specimens during the extended fatigue tests.
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Estudos da proteção à corrosão da liga de alumínio AA7075-T6 por revestimentos a base de polianilina / Corrosion protection of the aluminum alloy AA7075-T6 by coatings based on polyanilineRafael Marinho Bandeira 14 July 2017 (has links)
Neste trabalho foram formados, sobre uma superfície de liga de alumínio AA7075-T6, revestimentos de polianilina (PANI) e da blenda polianilina/policloreto de vinila na proporção massa-massa de 1/1 (PANI/PVC 1/1), com diferentes espessuras. Os revestimentos foram avaliados quanto as suas habilidades na proteção da corrosão da liga de alumínio. Utilizou-se uma solução de NaCl 3,5%, como solução corrosiva em todos os ensaios de corrosão. A espessura dos revestimentos de PANI foi variada de 5 a 35 µm e estudou-se a relação entre espessura, rugosidade e hidrofobicidade e a proteção por estes revestimentos. Os revestimentos com espessuras de 12 a 23 µm apresentaram menor rugosidade, maior ângulo de contato e melhor proteção da corrosão verificada por medidas eletroquímicas, tais como espectroscopia de impedância eletroquímica e polarização linear. As imagens obtidas por microscopia eletrônica de varredura mostraram que os revestimentos de PANI são homogêneos e que não exibiam defeitos decorrentes da exposição no ambiente corrosivo. Já a blenda, apresentou um desempenho maior na proteção da corrosão quando comparado com a PANI pura. Medidas de espectroscopia de impedância eletroquímica e de polarização linear mostraram que a blenda possui alta resistência de polarização, com potenciais de corrosão estáveis e deslocados à região anódica para os eletrodos com revestimentos de maior espessura (26,3 ± 0,9 µm). Imagens obtidas por microscopia eletrônica de varredura e de força atômica, juntamente com a análise de composição por espectroscopia de energia dispersiva de raios-X (EDX) contribuíram para entender a maior eficiência de proteção promovida pela blenda. / In this study, an aluminum alloy (AA7075-T6) was coated with polyaniline (PANI) and polyaniline/polyvinyl chloride (PANI/PVC in 1:1 ratio by mass) blend coatings of different thickness. These coatings were evaluated for their ability to protect the aluminum alloy against corrosion. For studying the corrosion of aluminum alloy in saline environment, a 3.5% NaCl solution was used in all the corrosion tests. The thickness of PANI-based films was varied between 5 to 35 µm and the effect of film thickness, roughness and hydrophobicity on the corrosion protection properties of the coatings was evaluated. The coatings with thickness between 12 and 23 µm exhibited lower roughness, higher contact angles and better corrosion protection as confirmed by electrochemical measurements such as electrochemical impedance spectroscopy and linear polarization. Morphological analysis by scanning electron microscopy confirmed that the PANI coatings are homogeneous and present almost no defects upon exposure to the corrosive environment. Compared to pure PANI coatings, the coatings consisting of PANI/PVC blend presented better performance against corrosion. Electrochemical impedance spectroscopy and linear polarization measurements showed that the blends have high polarization resistance with stable corrosion potentials that are shifted to the anodic region for the electrodes with thicker coatings (26.3 ± 0.9 µm). Surface analysis by scanning electron microscopy, atomic force microscopy and elemental analysis by energy-dispersive X-ray spectroscopy were used to gather information that helped understanding the better corrosion resistance of PANI/PVC coatings.
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Etude des interactions matériau/procédé en vue d'une optimisation des conditions opératoires du procédé de fabrication additive SLM sur des alliages d'aluminium pour des applications aéronautiques. / Study of the material / process interaction in order to optimize the operating conditions of the SLM additive manufacturing process applied to aluminum alloys.Galy, Cassiopee 28 June 2019 (has links)
La fusion laser sélective d’un lit de poudres (Selective Laser Melting – SLM) connait un véritable essor depuis quelques années,notamment en ce qui concerne la production de pièces métalliques. La faible densité des alliages d’aluminium, conjuguée à l’optimisation de conception rendue possible grâce aux procédés de fabrication additive, assure un gain de masse des structures conséquent, ce qui intéresse fortement les industriels des domaines automobile et aéronautique. Cependant, les propriétés finales des pièces aluminium fabriquées par SLM dépendent des nombreux défauts sont générés lors de la fabrication (porosités, fissuration à chaud, état de surface, …). Cette thèse s’intéresse aux moyens de mieux maîtriser ces problèmes en explorant trois axes : Une identification et sélection des méthodes de caractérisations adaptées aux spécificités des matériaux métalliques élaborés par les procédés de fabrication additive « lit de poudre » a été mise en place. Par exemple, la comparaison de différentes méthodes de détermination de la densité relative de pièces nous a permis de montrer les avantages et inconvénients de chacune des techniques employées ; Une étude du moyen de fabrication SLM a mis en évidence l’influence de différents facteurs (flux de gaz, position des éprouvettes sur le plateau de construction, méthodes de dépôt de la poudre) sur les propriétés finales des pièces produites.Ces éléments ont un impact sur la densité des pièces, leurs propriétés de surface et leurs propriétés mécaniques. Nous avons ainsi constaté que la façon de positionner une pièce sur le plateau est une étape de la préparation d’une fabrication à ne pas négliger ; Les études paramétriques menées sur deux types d’alliages d’aluminium, AlSi7Mg0,6 et AM205, ont montré que la composition chimique de l’alliage d’aluminium employé influence de façon non négligeable le jeu de paramètres opératoires à appliquer pour fabriquer une pièce de manière optimale. La densité d’énergie volumique ψ, rapport de la puissance laser avec le produit de la vitesse de lasage, de la distance inter-cordons et de l’épaisseur de couche, est utilisée de façon classique pour l’optimisation des conditions opératoires en SLM. Nos études expérimentales à différentes échelles (1D et3D) ont permis de mettre en évidence les limites de ce critère. La combinaison de ces résultats à la simulation numérique du lasage d’un cordon de poudre a servi de base à la définition d’un premier modèle dont l’objectif sera à terme d’optimiser le choix des paramètres de fabrication. / Interest in selective laser melting (SLM) has been growing in recent years, particularly with regard to the production of metal parts.The low density of aluminum alloys, combined with the possible design optimization enabled by additive manufacturing processes,ensures a significant decrease in the mass of structures which is very interesting for manufacturers in the automotive and aerospaceindustries. However, it is difficult to control the final properties of aluminum parts manufactured by SLM because many defects, suchas porosity, hot cracking, and surface roughness, are generated during the process. To better understand how to optimize theperformance of SLM aluminium parts, several studies were conducted during this work: An identification and selection of characterization methods well-adapted to the specificities of metallic materials developedby powder bed additive manufacturing processes was established. For instance, the comparison of different methods ofdetermining the relative density of parts showed the advantages and disadvantages of each of the techniques; A study of the SLM machine highlighted the influence of various factors (gas flow, positions of specimens on the constructionplate, or methods of depositing the powder) on the final properties of the produced parts. These elements have an impacton the density of the parts, their surface properties, and their mechanical properties. We found that the positioning of a pieceon the tray is a critical step in the preparation of a build that is not to be neglected; Parametric studies carried out on two types of aluminum alloys—AlSi7Mg0,6 and AM205—have shown that the chemicalcomposition of the aluminum alloy used has a significant influence on the set of operating parameters required tomanufacture an acceptable aluminum alloy part. The energy density, ψ, which is the ratio of the laser power to the productof the lasing speed, the hatching distance, and the layer thickness, is conventionally used for the optimization of the operatingconditions in SLM. Our experimental studies performed at different scales (1D and 3D) have shown the limits of this criterion.The combination of these results with the numerical simulation of the lasing of a single powder bead served as a basis forthe definition of an initial model, the final objective of which will be to optimize the choice of manufacturing parameters.
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Análise de mesotextura pelas técnicas de difração de raios-x e difração de elétrons retroespalhados em laminados da liga de alumínio AA3104 H19 utilizados para a fabricação de latas de bebidas / Texture analysis by the techniques of x-ray diffraction and electron backscatter diffraction in aluminum alloys AA3104 H19 used for the manufacture of beverage cansTogni, Edson 28 June 2019 (has links)
O crescimento significativo da capacidade instalada de produção de laminados de alumínio no País deve-se ao crescente consumo de latas para bebidas, um sinal de confiança dos consumidores e de sucesso sem precedentes em termos de solução para o mercado de embalagens. A lata de alumínio pode ser reciclada infinitas vezes. Por isso, consagrou também sua unanimidade, devido ao enorme benefício da reciclagem, que reduz o consumo de energia para a produção do alumínio, preserva o meio ambiente, movimenta a economia, gerando empregos e fonte de renda na coleta, e promove a educação dos cidadãos para o desenvolvimento sustentado. O foco deste trabalho é o estudo da alteração da textura de uma liga de alumínio 3104-H19 nas várias etapas do processo de estampagem das latas de alumínio para bebidas através da análise dos resultados de mesotextura obtidos pelos método MEV( Microscópio eletrônico de Varredura)- EBSD (Electron Backscatter Diffraction), bem como a compreensão dos mecanismos da formação da textura e sua influência na conformação das latas de alumínio. A composição química da liga de alumínio foi avaliada através de espectroscopia de dispersão de energia (EDS-MEV) e espectrometria de emissão ótica. Analisou-se sua microestrutura através de microscopia ótica e microscopia eletrônica de varredura (MEV). Realizou-se o ensaio de textura cristalográfica pelo método (SEM- EBSD) nas etapas de estampagem do corpo da lata e em ângulos de zero, 45 e 90 graus em relação a direção de laminação. Avaliou-se o resultado da textura cristalográfica através de Figuras de Polo. A análise microestrutural do laminado revelou dois tipos de compostos intermetálicos com morfologia distinta, Al6(Fe,Mn) e Al12(Fe,Mn)3Si, espalhados não homogeneamente, junto a dispersoides bem distribuídos na matriz de alumínio. Observou-se que na chapa laminada a textura a zero 45 e 90 graus são diferentes e à medida que os estágios de conformação do corpo da lata vão avançando as texturas a 45 e 90 graus vão se modificando e ficando semelhantes a da textura a zero grau (direção de laminação). A textura típica de deformação para ligas de alumínio, latão {110} e cobre {112}, junto a textura Goss {110}, estavam balanceadas pela textura cubo {001}, típica de recristalização. / The significant growth in the installed capacity of aluminum rolled products in Brazil is due to the increasing consumption of beverage cans, a sign of consumer confidence and unprecedented success in terms of solution for the packaging market. The aluminum can be recycled endlessly. Therefore, it also consecrated its unanimity, due to the enormous benefit of recycling, which reduces energy consumption for the production of aluminum, preserves the environment, moves the economy, generates jobs and sources of income in the collection, and promotes the education of citizens for sustainable development. The focus of this work is the study of the alteration of the texture of a 3104-H19 aluminum alloy in the various stages of the process of stamping aluminum cans for beverages by comparing the mesotexture results obtained by SEM (Scanning Electron Microscope) EBSD (Electron Backscattered Diffraction), as well as the understanding of the mechanisms of texture formation and its influence on the conformation of aluminum cans. The chemical composition of the aluminum alloy was evaluated using energy dispersive spectroscopy (EDS-MEV) and optical emission spectrometry. Its microstructure was analyzed by optical microscopy and scanning electron microscopy (SEM). The crystallographic texture test (SEM-EBSD) was carried out in the stamping stages of the can body and at angles of zero, 45 and 90 degrees with respect to the rolling direction. The result of the crystallographic texture was evaluated through Polo Figures. Microstructural analysis of the laminate revealed two types of intermetallic compounds with distinct morphology, Al6 (Fe, Mn) and Al12(Fe, Mn)3Si, dispersed in a homogeneous manner, together with dispersoides well distributed in the aluminum matrix. It was observed that in the laminated plate the texture at zero 45, 90 degrees are different, and as the stages of conformation of the body of the can advance the textures at 45 and 90 degrees, they are changing and being similar to the texture at zero degree (direction of rolling). The typical deformation texture for aluminum alloys, brass {110} and copper , together with Goss texture , were balanced by the cube texture {001}, typical of recrystallization.
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