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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Refusão superficial a laser da liga com memória de forma Cu-11,8Al-3,2Ni-3Mn (% Peso) / Laser surface remelting of a Cu-11.8Al-3.2Ni-3Mn (wt. %) shape memory alloy

Silva, Murillo Romero da 10 February 2017 (has links)
Submitted by Alison Vanceto (alison-vanceto@hotmail.com) on 2017-08-30T12:06:28Z No. of bitstreams: 1 DissMRS.pdf: 7292710 bytes, checksum: b518987951bcfa31933df3cece2f16cf (MD5) / Approved for entry into archive by Ronildo Prado (ronisp@ufscar.br) on 2017-09-06T18:24:26Z (GMT) No. of bitstreams: 1 DissMRS.pdf: 7292710 bytes, checksum: b518987951bcfa31933df3cece2f16cf (MD5) / Approved for entry into archive by Ronildo Prado (ronisp@ufscar.br) on 2017-09-06T18:33:14Z (GMT) No. of bitstreams: 1 DissMRS.pdf: 7292710 bytes, checksum: b518987951bcfa31933df3cece2f16cf (MD5) / Made available in DSpace on 2017-09-06T18:34:27Z (GMT). No. of bitstreams: 1 DissMRS.pdf: 7292710 bytes, checksum: b518987951bcfa31933df3cece2f16cf (MD5) Previous issue date: 2017-02-10 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Shape memory alloys (SMA) are alloys that undergo martensitic transformation due to an external solicitation (temperature, stress, strain or magnetic field) and are capable of recovering permanent deformation when heated above a critical temperature. The most used shape memory alloys are Ti-Ni- and Cu-based. Cu-based SMA have some advantages due to better thermal and electrical conductivity, lower production cost and are easier to process. The main disadvantage of Cu-based SMA is its low ductility. This property is improved by decreasing the grain size and by a reduction of microstructural heterogeneities. This can be achieved at the surface of structural components after LASER remelting, through which the surface of the material is remelted by a LASER beam and solidifies under extremely high cooling rates. In this context, the aim of the present work is to investigate the influence of LASER surface remelting in the microstructure, thermal stability and mechanical properties of Cu-11.8Al-3.2Ni-3Mn (wt. %) SMA plates obtained by suction casting. The samples were characterized by optical and scanning electron microscopy, energy dispersive X-ray spectroscopy, electron backscatter diffraction, X-ray computed tomography, X-ray diffraction, differential scanning calorimetry as well as by tensile and microhardness tests. The results show that small shifts in the transformation temperatures occur due to the LASER treatment. It was observed that only the monoclinic β’1 martensitic phase formed in the as cast and LASER treated samples. The LASER treatment provided an improvement in mechanical properties with an increase of up to 162 MPa in fracture stress, up to 2.2% in fracture strain and up to 21 HV in microhardness when compared with the as-cast sample. This makes the surface remelting treatment a promising method for improving the mechanical properties of Cu-based SMA. / Ligas com memória de forma (LMF) sofrem transformação martensítica devido a uma solicitação externa (temperatura, tensão, deformação ou campo magnético) e são capazes de recuperar deformações permanentes quando aquecidas acima de uma temperatura crítica. Dentre as LMF mais utilizadas se destacam aquelas à base de Ti e Ni e aquelas à base de Cu. As à base de Cu apresentam vantagens devido a melhor condutividade térmica e elétrica, menor custo de produção e maior facilidade de processamento. A principal desvantagem das LMF à base de cobre é a baixa ductilidade. Uma forma de melhorar essa propriedade é promovendo uma diminuição no tamanho de grão e uma redução das heterogeneidades microestruturais. Isso pode ser obtido no tratamento de refusão superficial a LASER, no qual a superfície do material é refundida por um feixe de LASER e solidificada sob altas taxas de resfriamento. Nesse contexto, o objetivo da presente dissertação de mestrado é analisar a influência do tratamento de refusão superficial a LASER na microestrutura, na estabilidade térmica e nas propriedades mecânicas de placas da LMF Cu-11,8Al-3,2Ni-3Mn (% peso) obtidas através de fundição por sucção. As amostras foram caracterizadas por microscopia óptica e eletrônica de varredura, espectometria de energia dispersiva de raios X, difração de elétrons retroespalhados, tomografia computacional por raios X, calorimetria diferencial de varredura, difração de raios X, ensaio de tração e microdureza. A análise dos resultados mostrou que as temperaturas de transformação sofreram pequenas variações e nenhuma nova fase foi observada após o tratamento de refusão a LASER, sendo observada apenas a presença da fase monoclínica martensítica β’1. O tratamento propiciou uma melhoria nas propriedades mecânicas das placas obtidas por fundição por sucção, com um aumento em até 162 MPa na tensão de fratura, em até 2,2 % na deformação de fratua e em até 21 HV na microdureza, fazendo deste tratamento um método promissor para melhorar as propriedades mecânicas das LMF à base de Cu. / CNPq: 132132/2015-0 / FAPESP: 2015/04134-7
22

Refusion sous vide d’alliages de titane : comportement de l’arc électrique et conditions aux limites / Vacuum arc remelting of titanium alloys : Behavior of the electric arc and boundary conditions

Delzant, Pierre-Olivier 27 February 2018 (has links)
Dans le procédé de refusion à l’arc sous vide, la structure et la dynamique de l’arc électrique conditionnent les distributions spatiales d’énergie et de courant au sommet du lingot refondu. Ces distributions impactent fortement les champs de température et de vitesse du métal liquide, qui gouvernent les conditions de solidification du lingot et donc la qualité finale du produit. Une étude par mesures optiques, de la dynamique de l’arc aux longues échelles de temps lors de refusions industrielles d’alliages de titane a été entreprise. Cette analyse a été effectuée par une méthode qualitative, à l’aide d’enregistrements vidéo, et par une nouvelle méthode de diagnostic quantitative développée spécifiquement dans ce travail, à base de photodiodes. L’analyse de la dynamique de l’arc confirme la présence d’un mouvement d’ensemble de l’arc électrique lors de refusions d’alliages de titane et montre une forte corrélation entre la dynamique observée et l’intensité du brassage électromagnétique imposé. Nos résultats ont de plus permis de prédire la dynamique probable de l’arc dans des conditions non étudiées et de proposer de possibles origines à la dynamique observée. Enfin, une première approche de modélisation de cette dynamique dans le logiciel de simulation RAVEL est proposée afin d’étudier son impact sur la solidification du lingot. Ce travail présente également une modélisation détaillée des rayonnements thermiques émis au sommet du lingot, basée sur la méthode des radiosités / In the vacuum arc remelting process, the structure and dynamics of the electric arc are responsible for the spatial distributions of energy and current at the top of the remelted ingot. Those distributions strongly impact the ingot temperature field and the liquid metal velocity field, which govern the ingot solidification conditions, hence the final product quality. A study based on the optical measurement of the electric arc dynamics at a long time-scale during vacuum arc remelting of titanium alloys was undertaken. This analysis was performed either qualitatively using melt video recordings, or quantitatively by a new specifically developed diagnostic technique based on the use of photodiodes. The analysis of the electric arc dynamics confirmed the presence of an ensemble arc motion during vacuum arc remelting of titanium alloys and showed a strong correlation between the observed dynamics and the magnitude of the imposed electromagnetic stirring. Furthermore, our results allow to predict the arc dynamics in non-studied conditions and to propose possible origins for the observed behaviors. Finally, a first simulation of the influence of the arc behavior is proposed in order to study its impact on the ingot solidification. This work comprises also a detailed modelling of the thermal radiation at the ingot top, based on the radiosity method
23

Modélisation et étude de la macroségrégation au cours de la refusion à l'arc sous vide : application aux alliages de zirconium / Modeling and Study of the Macrosegregation during Vacuum Arc Remelting : Application to Zirconium Alloys

Revil-Baudard, Mathieu 09 July 2012 (has links)
Le procédé VAR (Vacuum Arc Remelting ou refusion à l'arc sous vide en français) est employé dans la production d'alliages à haute performance pour les industries aéronautique (aciers spéciaux, superalliages et alliages de titane) et nucléaire (alliage de zirconium). Comme pour tous les procédés de fonderie, la maîtrise de l'homogénéité chimique et de la structure métallurgique des lingots coulés par le procédé VAR constitue un enjeu industriel important. Les travaux présentés dans ce mémoire visent à identifier, pour les alliages de zirconium en particulier, les effets de la convection naturelle et de la convection forcée due au brassage électromagnétique sur la macroségrégation. Dans ce but, un modèle numérique a été développé. Il est basé sur la résolution couplée des équations de conservation d'énergie, de quantité de mouvement et de solutés, dans des conditions d'écoulement laminaire ou turbulent. La modélisation de la solidification tient compte du couplage fort entre le transport d'énergie et de solutés dans la zone pâteuse. Afin de décrire la microségrégation, la diffusion restreinte des solutés dans les phases liquides et solides peut être prise en compte. Parallèlement, deux électrodes chimiquement homogènes d'alliages Zircaloy-4 et M5® ont été spécialement refondues dans un four VAR industriel sur le site de CEZUS à Ugine (Savoie, France). La macroségrégation des lingots obtenus a été caractérisée.La comparaison entre les mesures expérimentales et les résultats de simulation a montré que pour un alliage dont l'intervalle de solidification est important (comme l'alliage Zircaloy-4), la convection solutale dans la zone pâteuse peut avoir une influence essentielle sur la macroségrégation de la région centrale du lingot. Par ailleurs, le mouvement de grains équiaxes lors de l'application d'un brassage électromagnétique de forte intensité semble accentuer significativement la macroségrégation dans la région externe du lingot. Pour un alliage dont l'intervalle de solidification est faible (comme l'alliage M5®), nous avons montré que la macroségrégation dépend plus spécifiquement de la convection forcée due au mode de brassage électromagnétique appliqué au cours de la refusion / Vacuum Arc Remelting (VAR) is used to produce high performance alloys for the aeronautic (special steels, superalloys, titanium alloys) and nuclear (zirconium alloys) industries. As for all casting processes, the control of the chemical homogeneity and the metallurgical structure in VAR ingots is an important industrial issue. The goal of this thesis is to identify, for zirconium alloys in particular, the effects of the natural convection and the forced convection due to the electromagnetic stirring on macrosegregation. To this purpose, a numerical model has been developed. It is based on the solution of the coupled transient energy, momentum and solute transport equations, under laminar or turbulent flow conditions. The solidification modeling accounts for a full coupling between energy and solute transport in the mushy zone. The finite diffusion of solutes in both solid and liquid phases can be taken into account to describe microsegregation. In addition, chemically homogeneous Zircaloy-4 and M5® electrodes have been specially remelted in an industrial VAR furnace at the CEZUS plant in Ugine (Savoie, France). The macrosegregation of the ingots has been measured. The comparison between the experimental measurements and the simulation results showed that for an alloy with a large solidification interval (like Zircaloy-4), the solutal convection in the mushy zone could have an essential influence on the macrosegregation in the inner part of the ingot. Furthermore, the motion of equiaxed grains caused by a strong stirring seems to seriously intensify macrosegregation in the outer part of the ingot. For an alloy with a small solidification interval (like M5®), we have shown that the macrosegregation depends more specifically on the forced convection due to the type of stirring applied during the remelting
24

Modifikace mikrostruktury hořčíkové slitiny Elektron 21 pomocí technologie elektronového paprsku / Modification of Elektron 21 magnesium alloy microstructure via electron beam treatment

Hanáček, Josef January 2018 (has links)
This work presents a basic research on the influence of electron beam technology modification on chemical, structural and phases changes of Elektron 21 magnesium alloy. The samples were systematically modified under various parameters of the electron beam and coatings on their respective surfaces were deposited via controlled plasma electrolytic oxidation (PEO) subsequently. The influence of the EB modification on the PEO coating formation was observed. Several samples with remelted fine-grained surface layer were obtained. Having a thickness of 10^1 to 10^3 µm, the average grain sizes in this layer were quantitatively evaluated. The performed EDS analysis revealed in identical chemical composition of the remelted surface layer and the original alloy material, despite the detected sample weight loss upon the EB treatment. XRD analysis revealed an increased content of Mg3(Nd,Gd) intermetallic phase in the remelted area. The PEO coatings were more compact and less porous as compared with their counterpart coatings on the original, unmodified alloy material.The results of the presented work showed, among others, a suitable microstructure and chemical composition of some of the modified samples that could potentially exhibit enhanced corrosion resistance as opposed to the unmodified material. The corrosion testing will be part of a follow-up study. More compact PEO coatings formed on some of the modified surface layers likely represent, too, a more durable variant as compared to the original material.
25

Modifikace povrchu kovových materiálů s využitím elektronového svazku / Surface Treatment Technology of Metallic Materials and its Applications using Electron Beam

Matlák, Jiří January 2019 (has links)
Fast deflection is one of the great advantages of an electron beam, making it possible to process a relatively large area at once and also to modify the distribution of the supplied energy. The dissertation deals with surface heat treatment with a focus on the effect of beam deflection on the process. Furthermore, the influence of processing speed and defocusing of the electron beam is studied. The principles of electron beam technology and the summary of surface heat treatment of various materials are presented in the literary part of the thesis. The experimental part is focused on the influence of process parameters on processing in the solid phase, carried out on steel 42CrMo4, and in in the liquid phase, carried out on alloy NiCrBSi. Especially changes in structure, hardness, shape of the processed area and wear resistance are evaluated on processed samples. The results are also evaluated from an energy perspective. Furthermore, an optimum combination of technological parameters is recommended for solid and liquid phase surface heat treatment.
26

Energy efficiency of smelting of scrap aluminium in HPDC facilities : Available and upcoming technologies

Racsi, Bogdan Radu January 2023 (has links)
The aluminium industry is anticipated to witness a surge in demand, with projectionsof a two to three-fold increase by 2050. Meeting environmental objectives andaddressing the growing emphasis on sustainability from both the industry andconsumers seeking eco-friendly products present significant challenges. Energyefficiency will be crucial in addressing these concerns. While primary aluminiumproduction consumes the majority of energy in the industry, the die-casting sector, asan energy-intensive segment, offers opportunities for enhancing energy efficiency. Inhousealuminium smelting in high-pressure die-casting (HPDC) foundries, primarilyemploying gas-fired shaft furnaces with preheating for improved energy efficiency, isa significant energy user.This research examines energy efficiency in High-Pressure Die Casting (HPDC)foundries, particularly in-house aluminium smelting. Utilizing literature reviewsand expert interviews, the study reveals efficient technologies, drivers and barriersto energy efficiency, and the importance of sustainability. The current absence ofwell-defined Best Available Techniques (BAT) and the absence of validated claims bymanufacturers in the HPDC sector emphasize the urgent need for extensive researchand empirical verification.The results from this study show that using gas-fired shaft furnaces is the optimalchoice for the next decade, with waste heat recovery as the primary energy efficiencymethod, supplemented by the implementation of energy management systems andstrategies. Induction furnaces may emerge as a viable future technology, contingenton significant electricity network expansion and low energy prices.
27

Nitrogen Without Oxygen : The effect of ferroalloys added after vacuum treatment on cleanliness of nitrogen-alloyed tool steel

Nilsson Hultén, Leo January 2021 (has links)
Nitrogen-alloyed tool steel is made at Uddeholms AB by adding high-nitrogen ferroalloy after vacuum degassing where introduced impurities are hard to remove. In this thesis two types of high-nitrogen ferrochromium are compared, a solid version and a powder cored wire. They are examined in crossection and 16 samples from four charges are examined with Pulse Distribution Analysis as well as systematic microscopy of polished cross sections. The PDA results missed smaller spinel inclusions shown in previous research to be detrimental. The wire form shows promise but more charges need to be evaluated before a conclusion is drawn. / Kvävelegerat verktygsstål tillverkas hos Uddeholms AB genom tillsats av kväverika ferrolegeringar efter vakumavgasning, och orenheter som introduceras i detta steg är svåra att avskilja. I den har uppsatsen jämförs två typer av kväverikt ferrokrom varav en i form av stycken och en i form av tråd med pulverkärna. De undersöks i tvärsnitt och totalt 16 prov från fyra charger undersöks med PDA (pulsfördelningsanalys) och systematisk mikroskopering i tvärsnitt. Resultaten från PDA missade mindre inneslutningar av spinell vilka tidigare har visat sig problematiska. Trådformen verkar lovande men fler charger behöver undersökas för att kunna dra en definitiv slutsats.
28

Simulation numérique du procédé de refusion sous laitier électroconducteur / A comprehensive model of the electroslag remelting process

Weber, Valentine 27 February 2008 (has links)
Le procédé de refusion sous laitier électroconducteur (Electro Slag Remelting ou ESR) est aujourd’hui largement utilisé pour la production d’alliages métalliques à haute valeur ajoutée, comme les aciers spéciaux ou les superalliages base nickel. La modélisation mathématique et la simulation numérique du procédé ESR présentent un grand intérêt puisque les études expérimentales sur installations industrielles sont coûteuses et souvent difficiles à mettre en oeuvre. Ainsi, afin d’améliorer la compréhension et la maîtrise de la conduite d’une refusion, un modèle prédictif a été développé dans le cadre de cette étude. Il décrit les transferts couplés de chaleur et de quantité de mouvement lors de la croissance et de la solidification d’un lingot, en géométrie axisymétrique. La résolution des équations est basée sur une approche de type volumes finis. Le modèle tient compte de l’effet Joule dans le laitier résistif, des forces électromagnétiques et de la turbulence éventuelle de l’écoulement des phases liquides. La zone pâteuse est traitée comme un milieu poreux. Le modèle permet notamment de prédire la formation de la peau de laitier solide qui entoure le laitier et le lingot. Par ailleurs, il offre l’avantage de simuler le comportement du lingot et du laitier après la coupure finale du courant.Le développement s’est accompagné d’une importante étape de validation. Quatre refusions à l’échelle industrielle ont ainsi été réalisées à l’aciérie des Ancizes (Aubert&Duval). Les observations expérimentales ont ensuite été confrontées aux résultats du calcul. La comparaison a montré que le modèle peut être utilisé afin de prédire le comportement du procédé, à condition d’accorder une attention particulière à l’estimation des propriétés thermophysiques du métal, et surtout du laitier. Enfin, afin d’illustrer l’utilisation du modèle comme support à la compréhension du procédé, nous avons étudié l’influence de la variation de paramètres opératoires tels que la profondeur d’immersion de l’électrode, le taux de remplissage ou la pression de l’eau de refroidissement. / Electro Slag Remelting (ESR) is widely used for the production of high-value-added alloys such as special steels or nickel-based superalloys. Because of high trial costs and complexity of the process, trial-and-error based approaches are not well suitable for fundamental studies and optimization of the process.Consequently, a transient-state numerical model which accounts for electromagnetic phenomena and coupled heat and momentum transfers in an axisymmetrical geometry has been developed. The model simulates the continuous growth of the electroslag remelted ingot through a mesh-splitting method. In addition, solidification of the metal and slag is modelled by an enthalpy-based technique. A turbulence model is implemented to compute the motion of liquid phases (slag and metal), while the mushy zone is described as a porous medium whose permeability varies with the liquid fraction, thus enabling an accurate calculation of solid/liquid interaction. The coupled partial differential equations are solved using a finite-volume technique.Computed results are compared to experimental observation of 4 industrial remelted ingots fully dedicated to the model validation step. Pool depth and shape are particularly investigated in order to validate the model. Comparison shows that the model can be used as a predictive tool to analyse the process behavior. Nevertheless, it is necessary to pay a particular attention to the estimation of the thermophysical properties of metal and especially slag.These results provide valuable information about the process performance and influence of operating parameters. In this way, we present some examples of model use as a support to analyse the influence of operating parameters. We have studied the variation of electrode immersion depth, fill ratio and water pressure in the cooling circuit.
29

Resistência à corrosão e simulação numérica da temperatura e tensões induzidas na refusão superficial a laser da liga aerospacial Al–1,5% Fe

Teleginski, Viviane 31 August 2012 (has links)
Made available in DSpace on 2017-07-21T20:42:38Z (GMT). No. of bitstreams: 1 VIVIANE TELEGINSKI.pdf: 4135573 bytes, checksum: d862e0fdfd063afd1dec2d86b22b4031 (MD5) Previous issue date: 2012-08-31 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / In this work, the aerospace alloy Al–1.5wt.%Fe was submitted to laser surface remelting (LSR). This process occurs thought the application of a localized laser radiation with high power density, causing fast heating and melting of the irradiated material, following with high rates of cooling causing the non-equilibrium solidification of the treated layer. In the present work a broad experimental survey was made in relation to microstructure, composition of the resulting phases, morphology characterization, microhardness and corrosion resistance of the treated layer and the results were compared with the untreated sample. Predictions through the numerical simulation were done relative to the thermal history, heating and cooling cycles, the depth of the treated layer and the thermal stress caused by sudden heating and cooling of the treated layer. The results indicate that the high cooling rates of the order of 104 K/s promoted the formation of metastable intermetallic phases and oxides. Due to the laser treatment there was an increase in microhardness, reduction in surface roughness and there was an increase in corrosion resistance about fourteen times on the studied electrolyte. These results indicate that laser surface remelting is an effective tool for upgrade the surface quality of parts that require high level performances. The RSL technique is a modern technology for surface processing and it is being applied in industry such as automotive, aerospace and energy. / Neste trabalho a liga aeroespacial Al–1,5%Fe foi submetida ao tratamento de refusão superficial a laser (RSL). O processo ocorre através da aplicação localizada da radiação laser com alta densidade de potência, acontecendo um rápido aquecimento e fusão do material irradiado, seguido de um resfriamento com taxas elevadas sendo que a solidificação da camada tratada ocorre em condições fora de equilíbrio. No presente trabalho realizou-se um amplo levantamento experimental quanto à microestrutura, composição das fases resultantes, característica da morfologia, microdureza e resistência à corrosão da camada tratada e os resultados foram comparados com a amostra não tratada. Através da simulação numérica foram previstos o histórico térmico, ciclos de aquecimento, resfriamento, profundidade da camada tratada e as tensões termicamente induzidas pelo brusco aquecimento e resfriamento provocado pelo processamento. Os resultados indicam que em consequência do resfriamento com taxas da ordem de 104 K/s houve a formação de fases intermetálicas metaestáveis e óxidos. Houve um aumento da dureza, redução da rugosidade superficial e aumento da resistência à corrosão em torno de quatorze vezes no eletrólito de ácido sulfúrico 0,1 mol/L. Estes resultados indicam que o tratamento de refusão superficial a laser é uma eficiente ferramenta para aprimorar a qualidade superficial de peças que exigem alto nível de desempenho. A técnica de RSL é uma tecnologia moderna de processamento superficial e vem sendo aplicada nas indústrias como automobilística, aeroespacial e de energia.
30

ESTUDO DA CAMADA TRATADA GERADA POR REFUSÃO SUPERFICIAL A LASER DA LIGA AL-1,5%FE

Bertoni, Jean Cleber 30 January 2015 (has links)
Made available in DSpace on 2017-07-21T20:43:46Z (GMT). No. of bitstreams: 1 Jean Cleber Bertoni.pdf: 7862049 bytes, checksum: 4c77f7ebc3fc211aac8ad8a7de58ccad (MD5) Previous issue date: 2015-01-30 / There are currently extensive research on aluminum alloys, mainly due to its wide application in the automotive and aerospace industries, due to the following characteristics, among them, low density, high thermal conductivity and high corrosion resistance at room temperature. Al-Fe alloys have a high degree of microstructural change due to changes in their properties when appropriate techniques are applied. The Al-Fe alloy was studied in the composition of 1.5% Fe by weight, which was subjected to the treatment laser surface remelting in order to enhance its surface characteristics. The characterization of these alloys in order to determine the variation of the chemical composition at different depths was performed by Grazzing incidence x-ray diffraction (GIXRD). In this technique, the angle of incidence of the X-ray beam was fixed and the detector moved in 2θ, it is possible to obtain the XRD patterns at different depths by varying the angle of incidence. In this work, the characterizations the micro and nano structural sample of alloy Al-1.5wt.%Fe treated by laser surface remelting (LSR) were performed, on the treated surface, as well as the transverse section, this study was performed at treated samples surface and at the isolated weld fillet on samples, where were applied laser beam speeds of 20, 40 and 60 mm / s. In this study we used different characterization techniques, such as, optical microscopy, scanning electron microscopy, energy dispersive spectroscopy, together with atomic force microscopy, and the Vickers hardness. Also in this work the technique of GIXRD was used to obtain depth profiles of near the surface chemical composition of the alloy. The analysis was performed in the micrometer range varying the angle of incidence between 0.5° to 6° in steps of 0.5° and analysis with incident angles 3° and 6° in steps of 0.02° for each 10 sec. As a result by examining the microstructure was characterized melted zone, the heat affected zone and the substrate, a particular features were found for each velocity of the laser beam, generally the treated area showed a more homogenous microstructure consisting of grains smaller feature, with low roughness and high hardness. The heat affected zone was more notorious the morphology of grains elongated feature in the treated and untreated interface for low laser beam scanning velocities. By means of the technique of X-ray diffraction various metastable phases were found, such as aluminum oxide, nitrides, etc., with different intensities of peaks as a consequence of the variation of angle of incidence. / Atualmente há uma ampla investigação sobre ligas de alumínio, principalmente devido a sua larga aplicação na indústria automotiva e aeroespacial, devido as seguintes características, entre elas, a baixa densidade, alta condutividade térmica e elevada resistência à corrosão a temperatura ambiente. Ligas de Al-Fe possuem um alto grau de modificação microestrutural, devido a mudanças em suas propriedades quando técnicas adequadas forem aplicadas. A liga Al-Fe foi estudada na composição de 1,5% de Fe em peso, a qual foi submetida ao tratamento de refusão superficial a laser de modo a aprimorar suas características superficiais. A caracterização dessas ligas com a finalidade de determinar à variação de composição química em diferentes profundidades foi realizado mediante a difração de raios X com ângulo de incidência rasante (DRXIR). Nesta técnica, o ângulo de incidência do feixe de raios X foi fixado e o detector moveu-se em 2θ, sendo possível obter os difratogramas em diferentes profundidades com a variação do ângulo de incidência. Neste trabalho, as caracterizações a nível micro e nano estrutural das amostras da liga Al-1,5%Fe tratadas por refusão superficial a laser (RSL) foram realizadas, tanto na superfície tratada e bem como na parte transversal, este estudo foi realizado nas amostras tratadas em toda a superfície, quanto nas amostras com trilhas isoladas que foram aplicadas as velocidades de feixe laser de 20, 40 e 60 mm/s. Para isso foram utilizados diferentes técnicas de caracterização, tais como, microscópio ótico, microscópio eletrônico de varredura, espectroscopia por energia dispersiva, acompanhada da microscopia de força atômica, bem como da microdureza Vickers. Também neste trabalho a técnica de DRXIR foi utilizada para obtenção de perfis de profundidade da composição química próxima à superfície da liga. A análise foi realizada em escala micrométrica por meio da variação do ângulo de incidência entre 0,5° a 6° com passos de 0,5°, bem como as análises com ângulos incidentes de 3º e 6º com passos de 0,02º a cada 10 s. Como resultado mediante o estudo microestrutural foram caracterizados a zona fundida, a zona afetada termicamente e o substrato, sendo encontradas características particulares para cada velocidade do feixe de laser, de modo geral a zona tratada mostrou ter uma característica microestrutural mais homogênea formada por grãos menores, com baixa rugosidade e de alta dureza. A zona afetada termicamente mostrou ser mais notória a morfologia de grãos com característica alongada na interface tratada e não tratada para baixas velocidades de varredura do feixe laser. Por meio da técnica de difração de raios X diferentes fases metaestáveis foram encontradas, tais como, óxido de alumínio, nitretos, etc, com diferentes intensidades de picos como consequência da variação do ângulo de incidência.

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