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Solving the mysteries of metallic glass
www.physorg.com ^ | 12/22/2008 | Provided by MIT

Posted on 12/22/2008 11:26:47 AM PST by Red Badger

- Researchers at MIT and the National University of Singapore have made significant progress in understanding a class of materials that has resisted analysis for decades. Their findings could lead to the rapid discovery of a variety of useful new kinds of glass made of metallic alloys with potentially significant mechanical, chemical and magnetic applications.

The first examples of metallic alloys that could be made into glass were discovered back in the late 1950s and led to a flurry of research activity, but, despite intense study, so far nobody had solved the riddle of why some specific alloys could form glasses and others could not, or how to identify the promising candidates, said Carl. V. Thompson, the Stavros Salapatas Professor of Materials Science & Engineering and director of the Materials Processing Center at MIT. A report on the new work, which describes a way to systematically find the promising mixes from among dozens of candidates, was published last week in Science.

Glasses are solids whose structure is essentially that of a liquid, with atoms arranged randomly instead of in the ordered patterns of a crystal. Generally, they are produced by quickly cooling a material from a molten state, a process called quenching.

“It is very difficult to make glasses from metals compared to any other class of materials, such as semiconductors, ceramics and polymers,” Thompson said. Decades of effort by scientists around the world have focused on “understanding and on exploiting the remarkable properties of these materials, and on understanding why some alloy compositions can be made into glasses and others cannot,” he said.

They still haven’t solved that “why,” Thompson said. But this new work does “provide a very specific and quantitative new insight into the characteristics of liquid alloys that can most readily be quenched into the glassy state,” he said, and thus provides a much more rapid way of discovering new alloys that have the right properties.

The research was the result of a collaboration between Thompson and MIT post-doc Johannes A. Kalb with Professor Yi Li and graduate student Qiang Guo at the National University of Singapore, working together across thousands of miles of separation through the Singapore-MIT Alliance. Essentially, the work consisted of producing an array of different alloys with slightly varying proportions of two metals, each deposited on a separate microscopic finger of metal. Then, they analyzed the changes in density of each different mixture when the glass crystallized, and found that there were a few specific proportions that had significantly higher density than the others — and those particular alloys were the ones that could readily form glasses. Of three of these special proportions they found, two were already known glass-forming alloys, but the third was a new discovery.

The new work could even lead to a solution to the longstanding puzzle of why only certain alloys make glasses, he said. “I expect these new results, and the technique we developed to obtain them, will play a key, and hopefully decisive, role in solving the mystery of metallic glass formation.”

Such materials could have a variety of applications because of their unusual physical and magnetic properties, Thompson said. They are “soft” magnetically, meaning that it’s very easy to change the magnetic orientation of the material. This is a highly desirable characteristic for the cores of transformers, for example, which must switch their magnetic orientation dozens of times per second. Transformers made from metallic glasses could potentially greatly reduce the amount of electricity wasted as excess heat in conventional transformers, reducing the need for new generating plants.

In addition, these glasses are unusually hard mechanically and have a high degree of springiness (known technically as a high “elastic modulus”). This springiness could make them a useful material for some sports equipment such as golf clubs or tennis rackets, Thompson said. Although metallic glasses are relatively expensive, he said, for some people interested in the best-performing sports equipment, or in virtually unbreakable housings for cellphones, for example, “no expense is too high.”

The new research is a major accomplishment for the Singapore-MIT Alliance, Thompson said, and would not have been possible without the high-quality communications and collaboration tools it provides. Despite their physical separation, “Prof. Li and I have been working together now for almost ten years,” he said. “We routinely meet via video conferencing and have both been deeply involved in the co-supervision of the remarkable PhD student, Qiang Guo, who carried out this research.”

Thompson said he sees such collaborations as a significant example of a growing trend. “I think this and other accomplishments within the SMA program demonstrate that the future of research lies in technology-mediated collaborations among people with common interests and complementary capabilities, regardless of where the different parts of the team are located,” he said.


TOPICS: Business/Economy; Culture/Society; News/Current Events; Technical
KEYWORDS: aluminum; transparent

Computer!.......

1 posted on 12/22/2008 11:26:50 AM PST by Red Badger
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To: Red Badger

I was think of transparent aluminum myself...


2 posted on 12/22/2008 11:28:41 AM PST by thackney (life is fragile, handle with prayer)
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To: Red Badger

Doesn’t mean transparent.


3 posted on 12/22/2008 11:29:30 AM PST by RightWhale (We were so young two years ago and the DJIA was 12,000)
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To: Red Badger

4 posted on 12/22/2008 11:29:30 AM PST by BGHater (Obama is a Neocon.)
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To: Red Badger

“A keyboard! How quaint!”


5 posted on 12/22/2008 11:30:45 AM PST by AU72
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To: Red Badger
...new insight into the characteristics of liquid alloys that can most readily be quenched into the glassy state,”

Looks like this guy's got it down pat...


6 posted on 12/22/2008 11:31:05 AM PST by COBOL2Java (Obamanation: an imploding administration headed by a clueless schmuck)
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To: COBOL2Java

I regularly consume a liquid alloy that turns my eyes into a glassy state.


7 posted on 12/22/2008 11:34:27 AM PST by saganite
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To: AU72

Which way to the nuclear wessels?


8 posted on 12/22/2008 11:35:07 AM PST by Ingtar (For the first time in my adult life, I am NOT proud of America.)
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To: RightWhale

Picky, picky!..........


9 posted on 12/22/2008 11:35:23 AM PST by Red Badger (I was sad because I had no shoes to throw, until I met a reporter who had no feet.....)
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To: BGHater
Scotty had the last laugh. Transparent aluminum has been known since the time of the ancients. It's just aluminum oxide (Al2O3), aka sapphire.
10 posted on 12/22/2008 11:36:43 AM PST by B-Chan (Catholic. Monarchist. Texan. Any questions?)
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To: Red Badger
The first examples of metallic alloys that could be made into glass were discovered back in the late 1950s

I believe the Art Bellian legend has it that this was among the advances back-engineered from the crashed Roswell craft.

(insert theremin music here)

11 posted on 12/22/2008 11:37:02 AM PST by JennysCool (Internet Powerhouse)
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To: AU72

McCoy: You realize that by giving him the formula you’re altering the future.

Scotty: Why? How do we know he didn’t invent the thing?


12 posted on 12/22/2008 11:37:55 AM PST by Slapshot68
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To: B-Chan

Or Ruby or Emerald..........


13 posted on 12/22/2008 11:40:40 AM PST by Red Badger (I was sad because I had no shoes to throw, until I met a reporter who had no feet.....)
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To: Red Badger
Researchers at MIT and the National University of Singapore

Remember the "ceramic engine"?

Way back in Engineering School that's all we talked about in the thermodynamics lab.

It went the way of earth shoes.... and where Global Warming will go soon.

14 posted on 12/22/2008 11:43:05 AM PST by Mikey_1962 (Obama: The Affirmative Action President)
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To: Red Badger
I worked with metallic glasses at a certain very large high-tech company back in the late '70's. They are very interesting materials; they don't look like glass at all. The material I worked with looked like a metal tape. Shiny on one side, dull on the other side. The dull side was the side that was in contact with the cooling surface, which was, in my case, a very rapidly spinning, water cooled copper wheel.

At that time, commercially available quantities of this material, which was called Metglas, cost about $10K per pound.

15 posted on 12/22/2008 11:44:13 AM PST by Steely Tom (RKBA: last line of defense against vote fraud)
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To: Mikey_1962
ahhh, yes, "ceramics!"

Roughly concurrent with Solidarity and the Nuclear Winter.

Dam I loved the '80's.

16 posted on 12/22/2008 11:45:23 AM PST by the invisib1e hand (appeasement is collaboration.)
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To: Mikey_1962
Remember the "ceramic engine"?

http://www.youtube.com/watch?v=7Q0PcqqfA90

17 posted on 12/22/2008 11:46:28 AM PST by Red Badger (I was sad because I had no shoes to throw, until I met a reporter who had no feet.....)
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To: the invisib1e hand

http://en.wikipedia.org/wiki/Nuclear_winter

Maybe we need to RETURN to nuclear testing to avoid global warming < /sarcasm >

Damn commies.


18 posted on 12/22/2008 11:51:14 AM PST by weegee ("Let Me Just Cut You Off, Because I Don't Want You To Waste Your Question" - B.Obama Dec 16, 2008)
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To: Red Badger

Metallic Glass. Sounds the name for a wicked speed metal band.


19 posted on 12/22/2008 11:58:27 AM PST by Army Air Corps (Four fried chickens and a coke)
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To: the invisib1e hand

tut, tut, tut, please don’t forget the “peace dividend”


20 posted on 12/22/2008 12:05:09 PM PST by fortunate sun (Tagline written in lemon juice.)
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To: Red Badger

Ruby, yes: Emerald,no: while an aluminum oxide, it’s beryllium-aluminum oxide. . . .ruby is pure aluminum oxide, doped with chromium. . .


21 posted on 12/22/2008 12:12:50 PM PST by Salgak (Acme Lasers presents: The Energizer Border: I dare you to try and cross it. . .)
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To: weegee
Maybe we need to RETURN to nuclear testing to avoid global warming

Capital idea!

22 posted on 12/22/2008 12:23:53 PM PST by the invisib1e hand (appeasement is collaboration.)
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To: the invisib1e hand
Maybe we need to RETURN to nuclear testing to avoid global warming

With all the frigid weather we're having around here, the other night a buddy of mine told me "If I believed there was anything to all this global warming stuff, I'd be outside right now emptying all my aerosol cans!!!!!"
23 posted on 12/22/2008 1:09:45 PM PST by BikerJoe
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To: thackney

Transparent Aluminum!

It was the first thing I thought of also. I clicked on the thread, saw the picture, and just cracked-up. Life imitating Art you could say.

PF


24 posted on 12/22/2008 1:24:02 PM PST by PresidentFelon
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