Modelling Eutectic Growth in Unmodified and Modified Near-Eutectic Al-Si Alloy

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A numerical model that describes solidification of primary aluminium grains and nucleation and growth of eutectic cells is used to analyse the solidification of an Al-12.5wt% Si alloy. Nucleation of eutectic cells is modelled using an Oldfield-type nucleation model where the number of nuclei in the melt is determined by the amount of active nuclei and the local undercooling from the surface to the centre of a plate casting. Eutectic grains are modelled as spheres growing between the dendrites. The growth velocity of the eutectic cells is a function of undercooling. Experimentally determined growth parameters from the literature that depend on the type of modification (unmodified, Na-modified or Sr-modified) are used to describe differences in growth of the alloys. Modelling results are compared with solidification experiments where an Al-12.5wt%Si alloy was cast in unmodified, Na modified and Sr modified forms. The model confirms experimental observations of how modification and alloy composition influence nucleation, growth and finally the size of eutectic cells in the alloys. Modelling results are used to explain how cooling conditions in the casting act together with the nuclei density in the liquid and the growth velocity of the eutectic cells to determine the size and distribution of eutectic cells in the solidified material.
Original languageEnglish
JournalMaterials Science Forum
Volume765
Pages (from-to)160-164
Number of pages5
ISSN0255-5476
DOIs
Publication statusPublished - 2013
Event 6th International Light Metals Technology Conference - Windsor, United Kingdom
Duration: 24 Jul 201326 Jul 2013
http://www.lmt2013.com/

Conference

Conference 6th International Light Metals Technology Conference
CountryUnited Kingdom
CityWindsor
Period24/07/201326/07/2013
Internet address
CitationsWeb of Science® Times Cited: No match on DOI

    Research areas

  • Solidification, Eutectic, Modeling, ENGINEERING, METALLURGY, GRAINS, Modelling

ID: 91514703