Re: [CAD_CAM_EDM_DRO] stiff composites for machine construction

The weakest part will be the matrix. In ordinary steel, it is not the
precipitated crystals that fail - it's the 'matrix' between them that fails.
I would expect the same failure mode if you have strong carbide in a weak
aluminum matrix, and you subject it to high stress. However, if you're
looking for good dampening, that's another story.

Myron Cherry

----- Original Message -----
From: "Elliot Burke" <elliot@...>
To: "CAD_CAM_EDM_DRO" <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Sunday, November 17, 2002 6:43 PM
Subject: [CAD_CAM_EDM_DRO] stiff composites for machine construction


> While pondering the virtue of granite in an epoxy matrix as a machine
> structural material, I shifted gears and started thinking about silicon
> carbide in some sort of matrix.
> SiC has great advantages over granite and almost all other structural
> materials:
> 1. stiffness (high)
> 2. density (low)
> 3. thermal expansion (low)
> 4. specific heat (high)
> 5. mechanical and chemical stability (high)
> 6. cost (low)
>
>
> It can be made into composites with epoxy or by filling up aluminum with
it.
> Possibly the internal damping would be high in the composite.
>
> It would be interesting to calculate the relative merits of SiC/aluminum
and
> tungsten carbide as a boring bar.
>
> A great deal of the mass of a machine tool is there to resist the stress
and
> vibration of the cutting forces, a superior structural material could
reduce
> this weight dramatically. Those of us who want desktop mills and lathes
> would benefit.
>
> I know of the SiC/Aluminum mix being used for telescope mirrors, does
anyone
> know of other structural uses for it?
>
> Elliot B.
>
>
>
>
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