Aluminum-Boron Composite?

One of my clients is working on a new mechanism that's going to require a
high performance control system.

Whenever this happens I start suggesting exotic materials to the
mechanical engineering team.  This isn't so much because I think that the
product will fail without them, or that I think they're a good idea
(they're 'exotic' because people are generally smart enough not to use
them, after all).  Rather, it's because if the ME team is thinking about
how to shut up the crazy systems engineer and his ideas of exotic
materials, one of the things they do is think of how to keep the
resonances up with _ordinary_ materials.  

(RCM-ers: basically once you've gotten all the other limiting factors out
of the way, the performance of a positioning system is limited by the
resonances of the hunk of stuff you're trying to shove around, so raising
the resonances as high as possible, and to some extent deadening them,
makes for a higher achievable bandwidth).

We've already dismissed Magnesium (goes "thunk" when you hit it, instead
of "piiiiiiiiing" like Aluminum, but its modulus is low and their
favorite machine shop is scared of flammable metal), Beryllium-Aluminum
alloys (stiff stiff stiff, but Marketing and that danged machine shop
whine about toxicity, of all things!), Stainless brace members (stiff,
but too heavy, too hard to figure out how to do Al on the inside and SS
on the outside), and my latest piece de resistance, Silicon Carbide
(stiffer than Be-Al, but totally wacko -- you may as well build the whole
thing out of glass -- but if I can make it seem to be even remotely sane
then other things start looking reasonable, no?).

I recall about ten years ago a lot of press on boron fibers in an
aluminum matrix making for a very stiff material.  Since then I haven't
heard about it, or if I have it's been one of those things that's always
10 years down the road.

Have any of you seen this used anywhere?  Seen any ink on it?  Have any
reason to believe it's any less wacko than building a heavy machine out
of silicon carbide and hoping that no one drops it off a forklift?

Thanks in advance.

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http://www.wescottdesign.com