Glassy metals

I read an article in Discover magazine about a class of materials that
are like metals but 3 to 6 times higher strength. They are created by
mixing various larger atoms into metal alloys. They can be melted and
cast into forms giving a precise shape and correct dimensions. When
they solidify they remain shiny, they do not cristallize.

When I read about these I immediatly thought of cars that weigh 400
lbs instead of 2000.

We can use these in heat shields or structures of airplanes and
spacecraft.

Zoltan

(Zoltan Szakaly) wrote in message . com...
I read an article in Discover magazine about a class of materials that
are like metals but 3 to 6 times higher strength. They are created by
mixing various larger atoms into metal alloys. They can be melted and
cast into forms giving a precise shape and correct dimensions. When
they solidify they remain shiny, they do not cristallize.

When I read about these I immediatly thought of cars that weigh 400
lbs instead of 2000.

We can use these in heat shields or structures of airplanes and
spacecraft.

Amorphous metals are nothing new. They have high tensile strength and
some interesting magnetic properties but have many limitations as
structural materials. They need to be solidified quickly to avoid
crystallization, severely limiting the maximum thickness. They are
mostly produced in ribbon form. They crystallize and lose their
properties when heated to pretty moderate temperatures. You cannot
weld or braze them.

See www.metglas.com

New combinations of mismatched atom sizes may be better at retarding
crystallization than the alloys currently used to produce amorphous
metal ribbons and thus allow their use in more applications. I still
doubt they would replace composites.

(Zoltan Szakaly) wrote in message . com...
I read an article in Discover magazine about a class of materials that
are like metals but 3 to 6 times higher strength.

Important question: 3 to 6 times stronger than which metals?

Looking at the www.liquidmetal.com website, it seems their Zr-based
alloys have a yield strength of about 275000psi. Which is high, but
there are stronger steels. For example, the various maraging steel
alloys range from 250 to 350ksi, about 5 to 7 times as strong as the
sheet steel in your car.

(I also have to comment that www.liquidmetal.com is also filled with a
lot of marketing hype, to the point that "liquid metal" is portrayed
against an incomplete range of alloys. You don't see the steel alloys
that are stronger than "liquid metal," nor do you hear about the
difficulties in shaping and forming the stuff.)

They can be melted and cast into forms giving a precise shape
and correct dimensions.

Getting them cast into their final shape is good, because I understand
they're a complete pain to machine.

When I read about these I immediatly thought of cars that weigh 400
lbs instead of 2000.

Good luck forming cars out of those amorphous metals. The inexpensive
forming operations favored for car components (rolling, stamping,
welding) probably would not work well with "liquid metal". You'd be
stuck with expensive casting operations for the whole body, and I
suspect the cost of "liquid metal" is pretty high. Zirconium isn't as
cheap as iron or carbon steel.

Automakers are not avoiding advanced materials because the materials
in cars are already super-strong. Rather, they're avoiding many weight
reducing materials because the advanced materials are too expensive or
too difficult to form. This is why you only see structural
carbon-carbon or carbon-epoxy composites in no-expense-spared racing
cars, and why titanium only finds a few niche applications within
cars.

We can use these in heat shields or structures of airplanes and
spacecraft.

I suspect that if "liquid metal" were used in a heat shield, it would
melt or at least devitrify/crystallize after the first re-entry.

Further, there ARE materials used in the aerospace industry that
deliver better strength and strength-to-weight performance than
"liquid metal." The commercial aircraft industry is somewhat like the
car industry - it sticks to aluminum because aluminum has an adequate
balance of cost, strength, weight, and formability. "Liquid metal"
might be strong enough and light enough for aircraft, but I doubt it
can economically replace aluminum.

Mike Miller, Materials Engineer

(Zoltan Szakaly) wrote in message . com...
I read an article in Discover magazine about a class of materials that
are like metals but 3 to 6 times higher strength. They are created by
mixing various larger atoms into metal alloys. They can be melted and
cast into forms giving a precise shape and correct dimensions. When
they solidify they remain shiny, they do not cristallize.

When I read about these I immediatly thought of cars that weigh 400
lbs instead of 2000.

We can use these in heat shields or structures of airplanes and
spacecraft.

Zoltan

Last time I read up on these, they had some... undesirable properties.
With reasonable heating they loose their amorphous aspect and with it
almost all structural strength; also they are similar to glasses in
that they are brittle, i.e. they shatter just like glass. Not great
in a car crash.

They have some interesting applications, like machine parts with very
low friction and outstanding resistance to wear. But I wouldn't want
to build an SSTO from them.

Btw, if you want to produce them in large quantities, it's a whole lot
easier in orbit... :-)

I thinking much the same Zoltan.. Theyt are lighter, you can spread them
thinner. Such as the skin of an aircraft, or as a covering for an older
aircraft.

Maybe even make a better unibody car or aircraft or space plane?

Mike


Zoltan Szakaly wrote:

I read an article in Discover magazine about a class of materials that
are like metals but 3 to 6 times higher strength. They are created by
mixing various larger atoms into metal alloys. They can be melted and
cast into forms giving a precise shape and correct dimensions. When
they solidify they remain shiny, they do not cristallize.

When I read about these I immediatly thought of cars that weigh 400
lbs instead of 2000.

We can use these in heat shields or structures of airplanes and
spacecraft.

Zoltan

On other tact, the magenetic properties, what are they and any ideas on
how to use them?

Bullet traines or what?

Mike


James Moughan wrote:

(Zoltan Szakaly) wrote in message . com...
I read an article in Discover magazine about a class of materials that
are like metals but 3 to 6 times higher strength. They are created by
mixing various larger atoms into metal alloys. They can be melted and
cast into forms giving a precise shape and correct dimensions. When
they solidify they remain shiny, they do not cristallize.

When I read about these I immediatly thought of cars that weigh 400
lbs instead of 2000.

We can use these in heat shields or structures of airplanes and
spacecraft.

Zoltan

Last time I read up on these, they had some... undesirable properties.
With reasonable heating they loose their amorphous aspect and with it
almost all structural strength; also they are similar to glasses in
that they are brittle, i.e. they shatter just like glass. Not great
in a car crash.

They have some interesting applications, like machine parts with very
low friction and outstanding resistance to wear. But I wouldn't want
to build an SSTO from them.

Btw, if you want to produce them in large quantities, it's a whole lot
easier in orbit... :-)

CDs that last for nearly for ever?

Good long lasting generators, effiecient power output, so you have less
going cause of friction?

Mike


Mike Miller wrote:

Abrigon Gusiq wrote in message ...
On other tact, the magenetic properties, what are they and any ideas on
how to use them?

Ferromagnetic amorphous metals are of quite a bit of interest in
electrical applications like transformers and solenoids.

Bullet traines or what?

Rather more mundane than that. Transformers, solenoids, power
supplies, magnetic data media, etc.

http://www.wtec.org/loyola/nano/US.Review/05_05.htm
http://www.reade.com/Products/Alloys...us-metals.html

Mike Miller, Materials Engineer

In article ,
(Mike Miller) writes:
|
| Automakers are not avoiding advanced materials because the materials
| in cars are already super-strong. Rather, they're avoiding many weight
| reducing materials because the advanced materials are too expensive or
| too difficult to form. This is why you only see structural
| carbon-carbon or carbon-epoxy composites in no-expense-spared racing
| cars, and why titanium only finds a few niche applications within
| cars.

Don't forget failure modes - mild steel fails very gracefully,
except for the rust issue, which is critical for safety-critical
constructions subject to uncontrolled abuse.

| Further, there ARE materials used in the aerospace industry that
| deliver better strength and strength-to-weight performance than
| "liquid metal." The commercial aircraft industry is somewhat like the
| car industry - it sticks to aluminum because aluminum has an adequate
| balance of cost, strength, weight, and formability. "Liquid metal"
| might be strong enough and light enough for aircraft, but I doubt it
| can economically replace aluminum.

Modern aluminium alloys are much better than they used to be
at avoiding "metal fatigue". I remember when aluminium bicycle
components were a disaster area for general use - they are now
as reliable as cast steel.

Are "glassy metals" resistant enough to that to be useful even
in the aerospace industry? I have no idea.


Regards,
Nick Maclaren.