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Bizarre Properties of Glass Allow Creation of "Metallic Glass"
VindictivePantz writes to mention that scientists have discovered some bizarre properties of glass and are already applying that knowledge to create what is being called "metallic glass." "The breakthrough involved solving the decades-old problem of just what glass is. It has been known that that despite its solid appearance, glass and gels are actually in a 'jammed' state of matter — somewhere between liquid and solid — that moves very slowly. Like cars in a traffic jam, atoms in a glass are in something like suspended animation, unable to reach their destination because the route is blocked by their neighbors. So even though glass is a hard substance, it never quite becomes a proper solid, according to chemists and materials scientists."
It's not "Metallic Glass", it's Transparent Aluminum ...
Guns don't kill people; Physics kills people! - John Lithgow as Dick Solomon on Third Rock From The Sun
So am I according to an ex-girlfriend. Thanks, I'll be here all week. Try the veal. Tip your waitstaff.
Well, there's spam egg sausage and spam, that's not got much spam in it.
My first thought is transparent aluminum from Star Trek IV. Only to discover we're closer than I'd think...
This is crap. There have been windows of old buildings "sagging" upwards. The old technology of making windowpanes resulted in glass of uneven thickness, and it makes sense to install it the thick side down. Sometimes the installers did not care enough.
I think you mean 'transparent aluminium"
Glass does not "flow". Perhaps you've read such articles, and they are assuredly all bullshit.
Materials scientists call glass an amorphous solid.
One of the interesting aspects of this article is how it highlights the usual thermodynamic balance between entropy and free energy. States of matter in the equilibrium phase attempt to simultaneously maximize entropy, a measure of the statistical likelihood of a given state, and minimize the amount of energy "stored" in the given arrangement of molecules.
The most favorable condition is often a compromise between maximum entropy and minimum energy as highly ordered states, such as tetrahedral or other crystalline arrangements, often act to reduce the amount of stored energy due to minimized interatomic and/or intermolecular interactions and related factors. Pure crystals of substances will often form because the energetic "advantage" of the highly ordered crystalline state is often great enough to overcome entropic barriers.
The model that the researchers propose is interesting because the crystalline state itself introduces a degree of energetic disadvantage due to what is described as "cramming" of the individual crystalline unit cells. I wonder what models they used to form their hypothesis that the glass would eventually form a perfectly crystalline state.
It's widely known and widely taught, but it's not so. Glass does not flow at any measurable rate at room temperature. Glass at room temperature is an amorphous solid, not a liquid.
First of all, we've known about metallic glasses for years. There's a melt-spinner in the basement of my matsci building that we use to make metallic glasses. Their properties have been fairly well-studied.
Second of all, I don't really like the experiment that these people conducted. They simulated atoms during solidification, but they used microspheres within ANOTHER medium. With glasses, during there is no matrix material within which other molecules are moving. I find their model and extrapolation to be questionable. We are still trying to thermodynamically understand the glass transition and the solid amorphous state compared to the solid crystalline state.
The Air Force created a few years ago a translucent aluminum. They want to use it for cockpits and such because it's stronger than glass and doesn't scratch nearly as easily.
To me, that's the stuff that was predicted in Star Trek.
Hey, how do you know parent isn't the guy that invented it in the first place?
make world, not war
I am a materials engineer at the University of British Columbia in Canada. I recently did a technical presentation on 'Bulk Metallic Alloys' which seems to be the category of materials this 'glass' falls into. BMG's are very exiting materials, their main advantage over traditional alloys is their ability to store energy in elastic deformation. Esentially, they are the worlds best spring material. However; Be careful with your application in using these materials, they may have properties of strong alloys, but they have failure characteristics simmilar to ceramics. Usually they can fail with little to no warning, and catastrophically at that. Crack formation cannot be tolerated. I would not be comfortable with using this material for plane wings. Possibly the landing gear. This material has its niche in underplating for bodyarmor. Send the bullets back. For more information, a good website is http://www.liquidmetal.com/
Aside from repeating the old myth that glass can actually sag over hundreds of years, the article says very little. Perhaps a bad summary.
The jist of linked the story is:
A group of scientists in Bristol, Canberra and Tokyo used a material (doesn't say what) analogous to glass, not glass. This material is easier to study. Using this material they claim they were able to understand better what happens on the atomic level as it solidifies, and why it never really becomes a crystal. Nowhere in the article does it explain why this will lead to "metallic glass"
Here is an abstract for the original article. Pretty complex wording, but nothing about metallic glass.
If the answer is war, you are asking the wrong question
... residents of glass houses may now throw stones.
Have gnu, will travel.
You're probably thinking of synthetic sapphire (which is aluminum oxide).
Thank you!! I was going to write something very much like this. Having earned two degrees in science, one a M.S. which largely dealt with material physics, I can say that all materials flow, given enough time. In fact, the term 'rheology' (the study of properties and deformation of materials) comes from the Greek verb rheo, meaning "flow." There's even a Plato quote in there: "All things flow." That being said, the ability of glass to flow is NOT what makes it special. Instead, it is that glass does not posses a crystalline structure, rather, it is an amorphous material. The chemical constituents that make up glass have not combined to form an orderly and repetetive atomic structure of regular, well defined chemical composition. This (at least in part) is what lends glass its special properties. I too had a public school teacher that tried passing on that same misconception, and yes, it is a shameful thing that it continues to get passed along, even by such "reputable" sites as livescience.
Please, no.
Single crystals of alumina (Al2O3) are transparent. They are known as sapphire if clear or blue. With slight chromium impurities, they are known as ruby. They are a ceramic, not a metal. There are three oxygen atoms for every two aluminum atoms, which makes it 60%at oxygen. It is not aluminum. It would make more sense to say your watch is made of oxygen, but not by much.
Just saying "aluminum" implies the metallic structure, which will never be transparent despite the fervent hopes of many a Star Trek fan. The inherent availability of free electrons in the conduction band of metallic aluminum will ensure that is will not be transparent in any thickness greater than a few hundred nanometers. Truly transparent, metallic aluminum would be a breakthrough on par with a working transporter.
IAAPhDMS (I Am A PhD in Materials Science), and this has been your Pedantic Slashdot Rant from a Expert(TM) for today.
Back on topic. These metallic glasses (Vitraloy and the like) have been around for a decade now and have very interesting properties. They are not, however, transparent. Not even a little bit.
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The internet is the greatest source of biased information in the history of mankind.
Glass is not a liquid of any kind, "technically" or otherwise.
Glass is a solid.
Glass is not a crystalline solid.
Glass is an amorphous solid.
Yes, I am a materials engineer.
Slashdot is my Mercer Box.
I thought this was an urban legend:
"The deceptively liquid-like behavior of glass can be seen when you look at glass in the windows of an old building. The glass begins to sag and distort internally over the centuries, due to the effect of gravity."
This was because old glass making techniques used a spinning wheel to flatten and cool the glass so that one edge was slightly thicker when it was cut into the desired pieces. The whole sagging myth was made up. A common citation for rebuffing the myth is egyption glass that has held its form for much longer than the old english buildings.
) Human Kind Vs Human Creation
) It'd be interesting to see how many humans would survive to serve us.
or this?