Avaliação do diagrama de fases Ni-Al-Nb e obtenção da estrutura eutetica NiAl-NiAlNb
AUTOR(ES)
Fernando Luis Garcia Urrutia Araujo
DATA DE PUBLICAÇÃO
2002
RESUMO
The solidification of an eutectic alloy results in two or more solid phases, which grow in cooperative form. Such phenomenon makes this type of alloy interesting for obtainment of in situ composites. An in situ composite shows different properties than the individual component phases, that can result in a material with interesting features with regards to mechanical, electric, magnetic or optical properties. The aim of the present work is to evaluate alloys in the Ni-Al-Nb system, containing the eutectic structure formed by NiAl and NiAlNb phases. The first part of the present study consisted of the obtainment of cast eutectic structure in an electric arc furnace under inert atmosphere, and their characterization by optical and electronic microscopy, thermal analysis technique, X-rays fluorescence and X-rays diffraction. After that, the eutectic alloys were processed by directional solidification in a Bridgman type inductive furnace. The directionally solidified samples were characterized in the same way as the cast samples. In addition, the high temperature stability of the directionally solidified samples was evaluated. Finally, cast and directionally solidified samples were evaluated through microhardeness Vickers testing. The results allowed to understand the NiAl-NiAlNb eutectic growth, its morphology, its behavior in high temperatures and some preliminary aspects of its mechanical properties
ASSUNTO(S)
compostos intermetalicos solidificação microestrutura
ACESSO AO ARTIGO
http://libdigi.unicamp.br/document/?code=vtls000265167Documentos Relacionados
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