Influência da convecção termossolutal nos espaçamentos dendríticos primários durante a solidificação direcional horizontal de ligas Sn-Pb
In order to investigate the effect of thermosolutal convection on the primary dendritic spacings of Pb–Sn hypoeutectic alloys, horizontal directional solidification experiments have been carried out. For this purpose, a water-cooled solidification experimental apparatus was developed and specimen...
| Autor principal: | NOGUEIRA, Márcio Roberto Alves |
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| Grau: | Dissertação |
| Idioma: | por |
| Publicado em: |
Universidade Federal do Pará
2014
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| Assuntos: | |
| Acesso em linha: |
http://repositorio.ufpa.br/jspui/handle/2011/5557 |
| Resumo: |
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In order to investigate the effect of thermosolutal convection on the primary dendritic
spacings of Pb–Sn hypoeutectic alloys, horizontal directional solidification experiments have
been carried out. For this purpose, a water-cooled solidification experimental apparatus was
developed and specimens were solidified in unsteady state heat flow conditions. A combined
theoretical and experimental approach is developed to quantitatively determine the
solidification thermal parameters: tip growth rates, thermal gradients and cooling rates. The
results also include transient metal/mold heat transfer coefficients, determined from
comparisons between the experimental thermal profiles in castings and the simulations
provided by a finite difference heat flow program. A comparison between theoretical models
that predict primary dendritic spacings with the experimental results generated in this study is
conducted. A comparative study between some experimental data of this work and those from
the literature proposed to predict the primary dendritic spacings during upward and downward
vertical unsteady-state directional solidification of Sn–Pb alloys have is presented. The
observation of the microstructures has indicated that the primary dendritic spacings have been
affected by the direction of growth, increasing in conditions of horizontal solidification when
compared with those obtained during upward and downward vertical solidification of Sn–Pb
hypoeutectic alloys analyzed. |