The sad news, for you, is that they aren't "strengtheners" that you can stir into the melt like you can add additives to oils or gasoline. So, your proposed application is outside of current state of the art.
There is some limited introduction to metal matrix composites (aluminum would be the metal matrix and SiC would be the composite reinforcement) in the web page below:
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Do a Google search on "SiC aluminum metal matrix composites" or "Sic/Al
composites" or other combinations.It isn't just melting and mixing.
You might also find useful information at the site below on metallurgy in general....
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And you can go to DWA Composites who started work in the SiC reinforced
Aluminum about 25 years ago.
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homogeneously blended and vacuum-hot-pressed into commercial scale billets as
large as 1,000 lbs. DRA billets are transformed into an almost limitless range
of wrought products using conventional extrusion, rolling, and forging
metalworking techniques.
business. As the first company to achieve market success with series production
of commercial and military aerospace components, DWA has the longest and most
progressive presence in the the DRA industry. Our dedication to DRA technology
and problem solving has enabled our customers to realize significant benefits
for their businesses. Those few words sort of summarize the type of technology needed to stick the Sic inside the Aluminum in a useful way... and it isn't mixing in the molten state for castings.
Good luck with your metal casting sculpture.
Jim