Half a croissant, on a plate, with a sign in front of it saying '50c'
h a l f b a k e r y
Like gliding backwards through porridge.

idea: add, search, annotate, link, view, overview, recent, by name, random

meta: news, help, about, links, report a problem

account: browse anonymously, or get an account and write.



designing amorphous metal alloys

  [vote for,

Part 1
I've recently become aware of an interesting material called amorphous metal. Metal is usually fairly ordered at an atomic scale (kind of like crystal). In contrast, amorphous metal is disordered at the atomic scale.

Amorphous metal (also known as "liquid metal") has several unique and desirable properties such as not shrinking when it cools (maybe making it suitable for injection molding), and being very resilient. Amorphous metal is so très chic apparently Apple intends to use it in future products.

One way of making amorphous metal (i.e. disordered at the atomic scale) is to cool it from a molten state very quickly. Cooling metal this quickly is very difficult.

The other way to make amorphous metal is by making an alloy with metal atoms of lots of different sizes. This is called the "confusion effect" because the atoms are so confused when cooling they can't form ordered atomic bonds. Because the atoms of an amorphous metal alloy are of different sizes, there is very little free space between the atoms (i.e. the small atoms fill the gaps around the bigger ones).

I have no idea how metallurgists come up with the recipes for new amorphous metal alloys, but I thought I'd throw them a suggestion (because, you know, experts love unsolicited advice from complete amateurs).

Part 2
Apollonian packing is a neat geometry curiosity, where the spaces between touching circles is filled with smaller touching circles. Circa 2000, mathematicians discovered some interesting new properties about Apollonian packing. I don't really understand all the details, but basically circles with curvature of certain integer value combinations fit together nicely, whereas most other combinations do not. (Go and read the linked article; it explains it much better than I can). Apollonian packing can also be extended to the third dimension to packing together spheres of different sizes.

Part 1 + Part 2
So I figure, if I were going to design an amorphous metal alloy I'd use the Apollonian packing maths to decide which metals would suitably fit together. (I'm assuming metal atoms have a reasonably well defined radius).

Anyway, not much of an idea, but I thought it just made it over the line of HB worthiness because it brings to people's attention two cool things (and how they could be combined).

xaviergisz, Aug 16 2010

Amorphous metal http://en.wikipedia...iki/Amorphous_metal
[xaviergisz, Aug 16 2010]

Circle Game http://www.ac-noume...ocs/circle_game.pdf
Packing circles within a circle turns a mathematical surprise. Ivars Peterson.
last sentence of the article reads:
This is all curiosity-driven research with no foreseeable application in mind, Lagarias observes. [xaviergisz, Aug 16 2010]

Criteria for formation of metallic glasses http://authors.libr...2093/1/LEEjcp03.pdf
The role of atomic size ratio [lurch, Aug 16 2010]

Aperiodic Crystals http://en.wikipedia.org/wiki/Quasicrystal
Were these gems the precursor to Amorphous Metals? They certainly share a few properties, but not all. (Long live Roger Penrose!) [Wily Peyote, Aug 16 2010]


       Way over my head but (+) (because, you know, complete amatures love unsolicited kudos from complete ignoramuses).   

       The negative spaces in the packing circle link remind me of Mandelbrot sets.   

       I'm confused. I thought metals were generally amorphous unless you go to the trouble of encouraging crystal growth. My knowledge is derived from crystal growth in steel. Oh well (+) for teching me something.
MisterQED, Aug 16 2010

       Seems to me Apollonian packing would produce rather nice crystals.
ldischler, Aug 16 2010

       Now I have to kill [xaviergisz] before his discoveries lead to the invention of the T-1000.
DrWorm, Aug 16 2010

       good point ldischler, most of the Apollonian packings shown in my link are regular/symmetrical, but at least one of them is nonsymmetrical which is the type I'd focus on.
xaviergisz, Aug 16 2010

       I kinda like the way to make glassy metal by confusion.
Ling, Aug 17 2010

       [morrison_m], have you seen how much of the Terminator series takes place inside foundries? That's practically a furnace!
DrWorm, Aug 17 2010


back: main index

business  computer  culture  fashion  food  halfbakery  home  other  product  public  science  sport  vehicle