Re: FW: [ATM] re Aluminium casting

[Woodchuck <djv@bedford.net>]

On Sun, 15 Aug 2004, Ellen Mackenzie wrote:

> Hasan wrote:
>
> Speaking of which, does anybody have any knowledge of metal matrix
> composites?  Would it be simple to mix in some sort of fibres or
> whiskers of aluminum crystals into aluminum alloy, to make a stiffer
> substance?
>
> I wasn't able to attend Stellafane this weekend, so I don't know what
> the state of the art is in ATM.
>
>
> Hasan
> Toronto, Canada
> _______________________________________________
>
> The most of the composite work done with aluminium as a matrix used boron
> fibres to increase the stiffness. Most of the work done experimentally using
> various exotic fillers was done under US government funding which means that
> the results are rarely published unless unsuccessful. My only suggestion is
> to surf the net for answers.
>
> Ellen

As long as we're discussing "non-traditional" materials, has anyone
used powder metallurgical techniques? (AKA sintered metal).  I ask
for two reasons:  maybe it is more accessible for the backyard
would-be foundryman, secondly I live in an area (s.central Penna.)
where there are several powder metallurgy firms -- maybe I can
scrounge materials and smarts if this is promising.  (Also we do
poltruded plastics hereabouts.)  I'm thinking that powder metallurgy
is more like the ceramic model, since the mould can be packed at
room temperature and then baked.  Since glass melting temperature
is obtainable without NASA's budget, perhaps the sintering temperature
for steel, cupric alloys, iron, aluminum or something even more
interesting might be more easily and cheaply obtained than a
traditional poured casting.  Could it be done by microwave?  I would
like nothing better than to "cast" various parts (focusers, mirror
mounts, whatever) from powdered metal, if the heating part is
uncritical.  Surely it doesn't need a long soaking heat for small
(1", say) cross-sections?  Clearly the heat is below the m.p. of the
metal in question.

Frankly, I'm scared of making a big cupola furnace and of handling
fifty pounds of molten metal at once.

Another non-traditional stuff is plastics with powdered metal fillers.
(About which I know nothing).

Dave
-- 
       Anyone pleading "not guilty" is obstructing justice!

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