Abstract
The chemistry of molten alloy plays an important role on grain refining. Small addition of alloying elements reduces the grain size of the as-solidified structures to some degree depending on the alloy efficiency. The effect of dissolved Ti has been studied on the microstructure of Al–Si foundry alloys cast conventionally and by semi-solid casting routes. It is shown that Ti in solution could restrict the grains and globules size in both processes. A parallel plate compression test machine was employed to study the effect of dissolved Ti on the rheological behavior of the billets. It was confirmed billets with higher dissolved Ti-content have superior flow.
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Notes
\( {\hbox{Sphericity }} = {\hbox{ }}\frac{{4\pi A}} {{P^2 }} \)where A is total area of primary particles and P is perimeter of liquid–solid interface. The closer the sphericity to one, the higher is the globularity of the particle.
\( S_{\hbox{v}} = \frac{4} {\pi }\frac{P} {A} \)
Commercial software for calculation of equilibria, thermodynamic properties and phase diagrams http://www.thermocalc.com
The temperature at which mass flow of the molten alloy changes to interdendritic flow.
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Acknowledgements
The work reported here is part of an NSERC-Discovery grant and NSERC-ALCAN-UQAC industrial research chair, Grant No. IRCPJ268528-01, on the “Solidification and Metallurgy of Al-alloys”. The authors would like to gratefully acknowledge financial support from Natural Sciences and Engineering Research Council of Canada, ALCAN International Limited, Centre Québécois de recherche et de développement de l’aluminium (CQRDA), la Fondation de l’UQAC and the endowment fund of UQAC. Joseph Langlais of ALCAN-ARDC, for his continued interest, and Omid Lashkari of our research group, for carrying out the rheological tests, are gratefully acknowledged.
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Dr. Reza Ghomashchi was Former NSERC-ALCAN-UQAC Professor and Chair holder; Now Director, Advanced Materials and Processing Research Institute, (http://www.ampr-institute.com/).
Shahrooz Nafisi is Research fellow, Facility for Electron Microscopy Research, McGill University, Montreal, Canada.
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Nafisi, S., Ghomashchi, R. The effect of dissolved titanium on the primary α-Al grain and globule size in the conventional and semi-solid casting of 356 Al–Si Alloy. J Mater Sci 41, 7954–7963 (2006). https://doi.org/10.1007/s10853-006-0866-1
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DOI: https://doi.org/10.1007/s10853-006-0866-1