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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
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.
Glass does not "flow". Perhaps you've read such articles, and they are assuredly all bullshit.
Materials scientists call glass an amorphous solid.
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.
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
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?