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."

Get the terminology straight ...

[Zero__Kelvin (151819)]

It's not "Metallic Glass", it's Transparent Aluminum ...

New band names.

[Digestromath (1190577)]

Either way, be prepared to see them as band names any minute now. Or perhaps the band name is "Metallic Glass", thier first album is "Transparent Aluminum"

Re:New band names.

[mosb1000 (710161)]

For those of you who don't know, that use of the LDS acronym is a refrence to Star Trek IV (the source of all this transparent aluminum talk).

I know these posts are not serous, but the term metallic glass does not refer to transparent metals, but rather metals with an amorphus structure. Metallic glass lacks the fracture points associated with the crystal lattice of metals. This means that metallic glass does not fagigue over time as normal metals would. I believe that metallic glasses were first discovered by rapidally cooling laminants of titanium (I think I read somewhere that a WW2 nazi scientist fisrt discovered them).

Metallic Glass Not Equal to Transparent Aluminum

[celtic_hackr (579828)]

Glass is Silcon based,
Transparent Aluminum is Aluminum based, it is also known as the gemstone White Sapphire and looks much like diamonds. In fact it has been used for diamond like effects, but doesn't have the brilliance of diamonds (due to different reflective indexes).

Glass MOHS: ~ 5.5
Transparent Aluminun: MOHS = 9. Much harder, better crystaline structure, denser.

And as far as the article's claims, all solids move, but glass definitely is an abnormal material.

So am I

[UnknowingFool (672806)]

is a hard substance, it never quite becomes a proper solid, according to chemists and materials scientists.

So am I according to an ex-girlfriend. Thanks, I'll be here all week. Try the veal. Tip your waitstaff.

Re:So am I

[RobinH (124750)]

is a hard substance, it never quite becomes a proper solid, according to chemists and materials scientists.

That's what she said.

Scotty...

[WolverineOfLove (1305907)]

My first thought is transparent aluminum from Star Trek IV. Only to discover we're closer than I'd think... [wikipedia.org]

Perpetuating old myths

[leob (154345)]

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 is crap. [wikipedia.org] 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.

Re:Perpetuating old myths

[ErkDemon (1202789)]

Yeah, when you're assembling irregular-thickness glass for stained glass windows, you put the thicker (heavier) end at the bottom. It makes the glass mounting more stable, and the glass less likely to fall out.

For larger sheets, you put the thicker (stronger) end of the glass sheet at the bottom, because the bottom of the sheet has to carry the weight.

Re:Perpetuating old myths

[by Anonymous Coward]

And not only that, the nonsense about glass not being solid because it isn't crystalline is another oft repeated chestnut that is incorrect. There are plenty of non-crystalline solids, like wood, bone, cement, and pink and white iced animal cookies. Also pancakes. A soft solid, yes, but solid nonetheless.

You could even make a case that silicon in its pure, glassy state is already a form of "metallic glass". It certainly looks like it.

Re:

[MightyYar (622222)]

This is crap.

Yeah, I can't believe they repeated this little urban myth. The whole article takes a huge credibility hit IMHO.

Not to mention how the last half is written so poorly that it ventures into incomprehensibility-land.

Gel

[Psychotria (953670)]

Additionally, I am wondering why the summary compares glass to gel. Gel is a colloidal solution.

Re:Perpetuating old myths

[Red Flayer (890720)]

You're right, it is crap... except that the effects we observe were due to the liquidity of glass... albeit when the glass was molten :)

There is another distortion effect that myth attributes to liquid flow of glass... if you observe old architectural glass, you may note "waviness" in the glass. This is cause by how sheet glass was made.

A leader is dipped into molten glass, then raised slowly. While the glass is pretty much of uniform thickness, there is distortion caused by variations in temperature as the sheet cools.

If you're looking at old houses, it's interesting to note what kind of distortion is present in the windows -- this can tell you how the glass was made, which in turn can tell you if it's likely that the glass is original to the house. One needs knowledge of the history of window fabrication, which is often regional... but I digress.

This is yet another example of something making sense, but not being accurate. Yes, glass is technically liquid. But, the flow rate is such that the effects we attribute to the liquidity of glass would take millions and millions of years to occur at STP. Typically any effects in glass that are due to liquid flow occurred during the hardening stage.

Glass is not "technically" liquid.

[gr3y (549124)]

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.

Re:Perpetuating old myths

[buddhaunderthetree (318870)]

Bingo. If glass flowed at any rate the glass vases found in Egyptian tombs would have been puddles. I can't believe this stuff still gets repeated.

Re:Perpetuating old myths

[gillbates (106458)]

I can't believe this stuff still gets repeated.

It gets repeated because this particular tidbit of misinformation happened to make it into a very popular undergrad chemistry textbook:

Glass is a complex mixture of silicates and is classified as an undercooled liquid.

College Chemistry with Qualitative Analysis, Sixth Edition, Nebergall, Holtzclaw, Robinson. p743, section 27.12

It didn't take much of a stretch, no pun intended, for the explanation of thickening of the bottom of cathedral windows to include this little tidbit.

Re:Perpetuating old myths

[Karloskar (980435)]

There are lenses in very old telescopes that still function perfectly. If glass flowed at room temperature they would become distorted.

Re:

[xlation (228159)]

Clearly.

      It's not uncommon for amateur telescopes to have mirrors accurate to within 1/10th of a wavelength. If glass flowed, it wouldn't take it very long to go out of figure.

Re:Perpetuating old myths

[karnal (22275)]

Get that glass to about 1300 degrees Fahrenheit and you can mold it like slightly-hard silly putty.

Great, now my hands are all burnt up. But I've got this really cool glass to .... hold with my feet!

Re:Perpetuating old myths

[JustinOpinion (1246824)]

Yup. That myth has been thoroughly debunked, yet it still gets repeated.

The article is full of meaningless or incorrect statements. Like:

Royall is part of a group of scientists who think that if you wait long enough, perhaps billions of years, all glass will eventually crystallize into a true solid. In other words, glass is not in an equilibrium state, (although it appears that way to us during our limited lifetimes).

As a researcher in the field, I can assure you that this isn't a controversial statement. We all agree that glasses are not at equilibrium. We all agree that the low-energy state for glasses is to crystallize, and that (in principle), if you wait long enough they will crystallize. The questions revolve around details like "how far from equilibrium?", "what are the implications of being non-equilibrium (e.g. on phase transitions)?", "what are the kinetics and dynamics?", "how long would it ~actually~ take for a given amount of change/flow/reconstruction/etc.?"...

Also, equating "equilibrium" with "being a solid" is total nonsense. (Solids, liquids, and gases can all be at equilibrium or far from equilibrium...)

In short, don't waste your time with this ridiculously hyped review of some otherwise interesting (but not revolutionary) science.

Re:Perpetuating old myths

[JebusIsLord (566856)]

Yeah, this article had me rolling my eyes... the "journalist" basically strung a bunch of urban legends together, and didn't even bother to use a grammar checker. He should be fired and made into a Fox News anchor.

misleading

[retech (1228598)]

The term glass refers to the structure/lattice. Not to the substance we commonly refer to as glass.

An illustration of thermodynamics

[edwebdev (1304531)]

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.

Re:

[mapsjanhere (1130359)]

Hmm, I usually see that as a typical case of kinetic over thermodynamic control. The material hardens faster in the higher energy state instead of slowly rearranging to the lower minimum.
The article has a serious flaw so in claiming that glass formation helps with fatigue; the main reason that you get metal fatigues is loss of ductility. Most glasses are brittle to begin with, and even if not, the same forces that allow crystal growth leading to embrittlement are active in the glass too.

terrible summary of not great science

[anmida (1276756)]

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.

Re:

[blair1q (305137)]

What's so hard to understand?

Quantum physics tells us that electrons prefer certain geometric arrangements about a nucleus.

Due to this, atoms prefer certain geometric arrangements that take advantage of this atomic-orbital energy function. If this allows for a repeating pattern, and the mechanical noise in the system is high enough to disrupt any non-optimal bonds, a repeating pattern will most likely form.

But if the gross arrangement of several atoms is stable to thermodynamic perturbation even though som

Re:terrible summary of not great science

[anmida (1276756)]

Yes, dear. I know that. However, there's some weird shit with the glass transition, in that it looks like a second-order thermodynamic transition, but it isn't. The volume and enthalpy of glass goes from that of it's kindred solid to that of a liquid, with the smooth glass transition joining the two regions. I think a big issue that needs to be discussed is, what exactly is a solid? The glass guys have an easy way of determining a solid: viscosity. If it has enough resistance to flow, they define it as a solid.

Its been around for a while

[hAckz0r (989977)]

Look at the plate on the front of those those golf club drivers that they won't let you use, or even this patent:
http://www.google.com/patents?id=Kq4yAAAAEBAJ&dq=4256039 [google.com] Filing date: Jan 2, 1979

Its also been used in large transformers for years. The "technology advance" here worth noting is in being able to produce it while casting/moulding objects that are not thin and flat. It had been done as sheets for years, but casting a part that is something like 7 times the strength of titanium is much more useful. Unfortunately, the problem to solve is its brittleness. Things that shatter are much less useful.

BMG

[Composite_Armor (1203112)]

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/ [liquidmetal.com]

Let's Make Chips!

[Doc Ruby (173196)]

Silicon [wikipedia.org] is a metalloid [wikipedia.org], which has some properties of a metal (or some degree of those properties), and some properties that nonmetals have instead. That's why it can be made into a semiconductor.

That isn't news. This is the big story of 20th Century technology. Exploiting the glass properties of this metalloid is the real news.

Transparent Aluminum...

[topham (32406)]

Transparent Aluminum isn't fiction and never was.
Al(2)O(3) is sapphire. Personally I wear a watch made of Titanium and Sapphire.

Re:Transparent Aluminum...

[dhovis (303725)]

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.

TFA is sensationalistic

[breem42 (664497)]

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 [nature.com] is an abstract for the original article. Pretty complex wording, but nothing about metallic glass.

In related news ...

[PPH (736903)]

... residents of glass houses may now throw stones.

Re:LIQUID ALUMINUM???????

[lastchance_000 (847415)]

I think you mean 'transparent aluminium"

Re:LIQUID ALUMINUM???????

[wass (72082)]

Hey, how do you know parent isn't the guy that invented it in the first place?

Re:LIQUID ALUMINUM???????

[jo7hs2 (884069)]

Liquid aluminum? I think you mean Transparent Aluminum. Oh, I see, you are using a keyboard. How quaint.

Re:LIQUID ALUMINUM???????

[Romancer (19668)]

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.

Re:LIQUID ALUMINUM???????

[v1 (525388)]

they also placed the glass with the thicker area on the bottom because it was heavier, and it's a better idea to put the heavier part of the glass nearer the bottom of the frame. This led to practically all of those panes being installed thicker-side-down. So I suppose you could say gravity was responsible for the pane thickness variance... indirectly.

Re:LIQUID ALUMINUM???????

[dbIII (701233)]

Because glaziers were not stupid and put the thick bits that could handle more load at the bottom.

Re:LIQUID ALUMINUM???????

[dissy (172727)]

Then why is the glass always thicker at the bottom of the window?

They are load bearing windows

Re:LIQUID ALUMINUM???????

[zapakh (1256518)]

Reading down, it seems that I was taken in. It's an urban myth that it's an urban myth that it's an urban myth.

It "wants" to be true, but it's composed of these things that are like pentagons, so it gets "jammed" somewhere between fact and fiction.

Re:Don't we already know this?

[by Anonymous Coward]

Glass does not "flow". Perhaps you've read such articles, and they are assuredly all bullshit.

Materials scientists call glass an amorphous solid.

Re:Don't we already know this?

[russotto (537200)]

I certainly don't want to nit-pick, but isn't this already widely known? I've read dozens of articles about how glass panes in very old buildings have settled to the point where the top is so thin it breaks at the barest touch, while the bottom of the panes have thickened to near-translucence. Even in high school (many moons ago) we were taught that glass is technically a liquid.

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.

Re:Don't we already know this?

[Grond (15515)]

Except, as noted above, that's not true at all [wikipedia.org]. You learned it in high school because you had a bad science teacher, and shame on "livescience.com" for perpetuating such nonsense. Glass is an amorphous solid, not a 'slow liquid.' It shares one or two characteristics with supercooled liquids [wikipedia.org], but it is different in several important ways.

Re:Don't we already know this?

[NobodyElse (1111905)]

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.

Re:Aluminium glass

[by Anonymous Coward]

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.

Re:Aluminium glass

[by Anonymous Coward]

You're probably thinking of synthetic sapphire (which is aluminum oxide).

Re:Aluminium glass

[by Anonymous Coward]

or this? [wikipedia.org]

Re:

[arb phd slp (1144717)]

A keyboard? How quaint.