MARIANA XAVIER MILAGRE
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Artigo IPEN-doc 26823 Effects of chloride ion concentration on the corrosion behavior of the AA2198-T8 alloy2019 - MACHADO, CARULINE de S.C.; SILVA, REJANE M. da; ARAUJO, JOAO V. de S.; DONATUS, UYIME; MILAGRE, MARIANA X.; KLUMPP, RAFAEL E.; ROSSI, JESUALDO L.; COSTA, ISOLDAIn this work, the influence of chloride ions concentration on the corrosion behavior of the AA2198-T8 alloy was evaluated. Immersion test and electrochemical analyses were performed in sodium chloride solutions of three concentrations, 0.001 mol L-1, 0.005 mol L-1 and 0.01 mol L-1. The results showed that the AA2198-T8 alloy was susceptible to localized corrosion (LC) and to severe localized corrosion (SLC) in all conditions investigated. The electrochemical results obtained by open circuit potential measurements, cyclic voltammetry and potentiodynamic polarization curves were associated with the corroded microstructure of the alloy. Although electrochemical techniques allowed differentiating the corrosion resistance as a function of chloride concentration, the result was strongly influenced by the corroded/uncorroded area ratio related to the SLC.Artigo IPEN-doc 25828 Study on welding thermal cycle and residual stress of UNS S32304 duplex stainless steel selected as external shield for a transport packaging of Mo-992019 - BETINI, E.G.; GOMES, M.P.; MILAGRE, M.X.; MACHADO, C.S.C.; REIS, L.A.M.; MUCSI, C.S.; ORLANDO, M.T.D.; LUZ, T.S.; MARTINEZ, L.G.; ROSSI, J.L.Thin plates of duplex stainless steel UNS S32304 were welded using the pulsed gas tungsten arc GTAW process (butt joint) without filler addition. The used shielding gas was pure argon and 98% argon plus 2% of nitrogen. The thermal cycles were acquired during welding, in regions near the melting pool. This alloy is candidate for the external clad of a cask for the transport of high activity radiopharmaceuticals substances. For the residual stress measurements in austenite phase an X-ray diffractometer was used in a Bragg-Brentano geometry with CuKα radiation (λ= 0.154 nm) and for ferrite phase was used a pseudo-parallel geometry with CrKα radiation (λ= 0.2291nm). The results of residual stress using sin2 methodology showed that the influence of the high welding temperature leads to compressive stresses for both phases of the duplex steels mainly in the heat-affected zone. It was observed a high temperature peak and an increase of the mean residual stress after addition of ni-trogen to the argon shielding gas.Artigo IPEN-doc 25326 Correlação entre difusividade térmica e tensão residual no aço inoxidável duplex UNS S32304 submetido a processo de soldagem TIG e tratamento térmico2018 - CAETANO, G.A.; ORLANDO, M.T.D.; LUZ, T.S.; MACEDO, M.C.S.; SOUZA, N.S. de; MILAGRE, M.X.; MACHADO, C.S.C.; ROSSI, J.L.As altas temperaturas do processo de soldagem podem afetar no desbalanceamento de fases e gerar tensões residuais, que podem prejudicar o desempenho do material. Neste trabalho foi feita uma correlação da tensão residual induzida pelo processo de soldagem TIG com a difusividade térmica. Corpos de prova de um aço inoxidável duplex UNS S32304 com espessura de 1,8 mm foram soldados em pares de modo autógeno, utilizando como gás de proteção uma mistura de argônio e 2% de nitrogênio. Seguido de tratamento térmico a 600 °C por 8h e resfriamento ao ar. A dureza foi avaliada através do ensaio de microdureza Vickers. A difusividade térmica foi determinada pelo método Flash Laser. E a tensão residual foi analisada pela técnica de difração de raios X, pelo método do sen²Ψ. Verificou-se que o comportamento da difusividade térmica no material se correlaciona diretamente ao comportamento da tensão residual presente na fase austenítica.Artigo IPEN-doc 24194 Study on welding thermal cycle and residual stress of UNS S32304 duplex steel selected as external shield for a transport packaging of Mo-992017 - BETINI, EVANDRO G.; GOMES, MAURILIO P.; MILAGRE, MARIANA X.; MACHADO, CARULINE S.C.; REIS, LUIS A.M.; MUCSI, CRISTIANO S.; ORLANDO, MARCOS T.D.; LUZ, TEMISTOCLES S.; ROSSI, JESUALDO L.