Obtenção e caracterização de materiais compostos In Situ no sistema Fe-Al-Nb

AUTOR(ES)
DATA DE PUBLICAÇÃO

1998

RESUMO

Eutectic alloys formed by high melting point intermetallics phases, as in the case of the system formed with Fe, Al and Nb elements are promising material to be used as structural materials. This system presents eutectic structures formed by (FeAl)2Nb phase surrounded by (FeAl) solid solution. Depending on solidification conditions the eutectic structures can be significantly changed. This fact allows one to control the final microstructure, which permits to obtain in situ composites. In this work, firstly the analysis of the Fe-Al-Nb phase diagram was carried out. The aim of this study was to determine the eutectic valley (Fe) + Fe2Nb with of AI content from 20 up to 50 at.%. Following that, the influence of growth rate was investigated using the directional solidification technique, with inductive heating and under argon atmosphere. The eutectic structures compositions, Fe67Al22,8Nb9,7, Fe49,7Al41,2Nb9,1 and Fe47Al45Nb8, were determined using optical and scanning electron microscopy, x-ray diffraction and thermal analysis. Finally in order to evaluated the mechanical behavior of these eutectics, compression and microhardness tests of directionally solidified samples were performed

ASSUNTO(S)

materiais compostos compostos metalicos cristais - crescimento solidificação

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