Orientador: Maria Helena Robert / Dissertação (mestrado profissional) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-16T19:01:24Z (GMT). No. of bitstreams: 1 Esposte_JulioCesar_M.pdf: 9041212 bytes, checksum: 491e0e0249f5348f5e35f599c930fc71 (MD5) Previous issue date: 2010 / Resumo: Este trabalho teve como objetivo a análise comparativa entre a liga Al-Si5-Cu3-Mg nos estados fundido sob pressão (injetado) e tixoconformado, tomando-se como base um componente comercial suporte de acessórios utilizado em motores a diesel. Caracterizou-se o componente comercial produzido pelo processo de injeção em termos de estrutura e propriedades mecânicas, e por sua vez o produto final obtido pelo processo de tixoconformação é também caracterizado nos mesmos termos a fim de se obter uma base comparativa. Para análise da tixohabilidade, ou seja, capacidade de obtenção de pastas tixotrópicas da liga em estudo, submeteu-se a mesma a análises térmicas utilizando técnicas de DSC, e através de simulação termodinâmica utilizando software THERMOCALC®. São discutidas as temperaturas de transformação e intervalos de solidificação, sugerindo-se janelas de tixoconformação para a liga. A liga foi submetida a tratamentos térmicos de globularização de 120 e 300s, para duas condições de frações sólidas, 45 e 60%, além da avaliação da influência de uma pré-formação a frio por compressão do lingote antes da tixoconformação. A liga mostrou-se interessante para a produção de pastas tixotrópicas, com intervalo de solidificação na ordem de 100°C, além de uma variação da fração líquida com a temperatura favorável para definição da janela de tixoconformação. Este comportamento tixotrópico permitiu o total preenchimento do molde e a obtenção de produtos tixoconformados de boa qualidade, com destaque para a diminuição dos teores de porosidade em comparação aos apresentados pelo componente injetado (cerca de 17 vezes inferiores). O material submetido à prévia deformação a frio apresentou glóbulos de diâmetros reduzidos, provenientes do mecanismo de globularização envolvido que passa pela recristalização do material, e consequente melhora das propriedades mecânicas em relação ao material sem deformação. O produto tixoconformado apresenta propriedades mecânicas que atendem às especificações do material estudado, embora apresentem, para algumas das condições de fabricação empregadas no trabalho, valores de limite de resistência e de dureza inferiores aos do material fundido sob pressão / Abstract: The goal of this work was the comparative study between the Al-Si5-Cu3-Mg alloy obtained by die casting and thixoforging, based on a commercial accessories bracket used in diesel engines. The die casting commercial part was characterized in terms of structure and mechanical properties, and the final sample obtained by thixoforging was characterized in the same terms, in order to have a comparative base. For thixoability analysis, in other words, the capacity to obtain thixotropic slurries of the alloy under study, it was evaluated by thermal analysis through DSC techniques and thermodynamic simulations using THERMOCALC® software. Transformations temperatures and ranges are discussed, proposing thixoforging windows. The alloy was submitted for globularization thermal treatments under 120 and 300s, and solid fractions 45 and 60%, beyond the influence evaluation of a preliminary cold forming before the thixoforging process. The alloy proved to be interesting to produces thixotropic slurries, with solidification range around 100°C, besides a favorable liquid fraction vs temperature to define the thixoforging window. This thixotropic behavior allowed the complete matrix filling and thixoforged samples were obtained with a good quality, highlighting the porosity decreasing in comparison with the die casting component (around 17 times less). Reduced globules sizes were obtained with previous cold forming, due to the involved globularization mechanism of the recrystallization, and consequent mechanical properties improving in face of non cold forming material. Thixoforged product presents mechanical properties according to the studied alloy specifications, although for some manufacturing conditions present lower tensile strength and hardness when compared with die casted component / Mestrado / Materiais / Mestre em Engenharia Automobilistica

3D-printing, också känt som additiv tillverkning, är en tillverkningsmetod som har revolutionerat många branscher och har växt stort både inom industrin och för privat användning. Tekniken använder sig utav en lager-på-lager metod för att tillverka olika objekt. Med dagens teknik går det att printa ut föremål av exempelvis metall, plast, betong och ett flertal andra material. Additiv tillverkning av betong ger möjligheten att skapa nya smarta konstruktionslösningar, vilket medför stora materialbesparingar och minskat materialspill. Produktionskostnader och hastighet kan också dra nytta av metoden genom att minska arbetskraft och eliminera kostnader för tillverkning och montering av gjutformar. Den här studien bidrar till en ökad förståelse för vad som krävs för att utveckla ett fungerande betongmaterial för additiv tillverkning. För att additiv tillverkning ska kunna standardiseras, bli mer kommersiellt och få en bredare användning krävs en djupare förståelse av betongens materialegenskaper. Detta eftersom materialet skiljer sig från konventionell betong. Syftet med detta projekt är att utveckla en betongblandning anpassad för additiv tillverkning. En undersökning görs för att hitta (i) en betongblandning med lämpliga mekaniska materialegenskaper och (ii) en betongblandning som är väl anpassad till 3Dskrivare. Det viktigaste för att en betongblandning ska kunna användas för additiv tillverkning är att blandningen kan pumpas genom systemet och extraheras genom munstycket vid tillverkning samt att slutmaterialet visar bra byggbarhet. Pumpbarhet är förutsättningen för att betongen ska kunna användas i en 3D-skrivare. Betongen ska vara tillräckligt smidig för att kunna pumpas ut genom ett munstycke, men även ha en tillräckligt god inre sammanhållning för att inte deformeras efter att den har pumpats ut. Pumpbarhet påverkas till stor del av vilken sorts pumpsystem som används. Resultaten varierar beroende på vilken pump, munstycke och slang som används vid materialtesterna. Det förefaller att en generell blandning anpassad för flera olika pumpsystem är svårt att uppnå. I det här arbetet har sex olika blandningar med olika variationer testats. Detta ledde till 38 blandningar som genomgått olika tester. De blandningarna med bäst resultat efter finjusteringar var blandning 4.1 och 5.1, de visade hög kvalité för pumpbarhet och byggbarhet. Blandning 4.1 innehåller vatten, anläggningscement, starvis 3040, glenium, CERW, krossballast och glasfibrer och blandning 5.1 är likadant fast med flygaska istället för CERW. / 3D printing, also known as additive manufacturing, is a manufacturing method that has revolutionized many industries and has grown widely both in industry and private use. The technique means using a layer-upon-layer method to manufacture different objects. With today's technology, it is possible to print objects of, for example, metal, plastic, concrete and several other materials. Additive manufacturing of concrete structures can be used to create new smart design solutions, which means significant material savings and reduced material waste. Production costs and time reduction may also be achieved using the method due to lower labor requirements and reduced costs for manufacturing and assembling of molds. This study contributes to an increased understanding of what is required to develop a functioning concrete material for additive manufacturing. In order for additive manufacturing to be standardized, become commercial and be broadly used, a deeper understanding of the concrete properties is required. This is because the material used in 3D printing differs from conventional concrete. The purpose of this project is to develop a concrete mixture adapted for additive manufacturing. A survey is made to find (i) a concrete mixture with suitable mechanical material properties, and (ii) a concrete mixture well adapted to 3D printers. The most important thing for a concrete mix to be used for additive production is that the mixture can be pumped through the system and extracted through the nozzle during manufacture and that the final material shows good buildability. Pumpability is a prerequisite for the concrete to be used in a 3D printer. The concrete must be sufficiently flexible to be pumped out through a nozzle, but also have a sufficiently good internal cohesion so as not to deform after it has been pumped out. Pumpability is largely affected by the type of pump system used. The results vary depending on the pump, nozzle and hose used in the material tests. It seems that a general mix adapted to several different pump systems is difficult to achieve. In this work, six different mixtures with different variations have been tested. This led to 38 mixtures that underwent various tests. The mixtures with the best results after fine adjustments were mix 4.1 and 5.1, they showed high quality for pumpability and buildability. Mixture 4.1 contains water, plant cement, starvis 3040, glenium, CERW, crush ballast and glass fibers and mixture 5.1 is similarly fixed with fly ash instead of CERW.