Featured Research

from universities, journals, and other organizations

UNC-CH Physicists Find Atoms Of Chilled Metallic Liquids Chiefly Move In Lockstep

Date:
November 12, 1999
Source:
University Of North Carolina At Chapel Hill
Summary:
For the first time, atomic-scale measurements have revealed that atoms in a metallic liquid cooled significantly below the melting point - also known as a super-cooled liquid -- chiefly move together in clustered lockstep.

CHAPEL HILL - For the first time, atomic-scale measurements have revealed that atoms in a metallic liquid cooled significantly below the melting point - also known as a super-cooled liquid -- chiefly move together in clustered lockstep.

The effect is something like that of a phalanx of ancient Greek soldiers marching into battle or commuters moving on the platform of a crowded subway.

Such information is important in part because it helps reveal and explain the behavior of liquids having a strong tendency to form bulk metallic glasses, a new class of engineering materials with highly unusual properties, scientists say. First reported in 1993, the materials have thousands of potential uses in industry, the military, sports and other areas.

"What we have done is to shed some light on the mechanisms of atomic motion in the glass transition temperature region, around 650 degrees Fahrenheit in the materials we were working with," said Dr. Yue Wu, associate professor of physics and astronomy at the University of North Carolina at Chapel Hill. "This could be significant for understanding the nature of glass transition, which occurs when liquid cools rapidly and changes from a molten form to an amorphous solid without crystallization.

"The transition is a universal phenomenon that's been observed in almost all materials and plays a key role in many areas from food preservation to the forming of glass art objects."

A report on the research appears in the Nov. 11 issue of the journal Nature. Besides Wu, authors are Drs. X.-P. Tang, assistant research professor in physics at UNC-CH, Ulrich Geyer of Gottingen University in Germany, Ralf Busch of Oregon State University and William L. Johnson of the California Institute of Technology.

The study involved examining slow beryllium atomic motion on both microscopic scales using nuclear magnetic resonance (NMR) and macroscopic scales using diffusion measurements in zirconium-based bulk metallic glasses, alloys discovered by Johnson and a student at Cal Tech.

Tang and Wu employed a new NMR technique they developed to determine how local environments of beryllium atoms change when motion occurs and the rate of such changes.

"Atoms in a chilled metallic liquid manage to move more efficiently as a group than individual hopping, although the latter survives better at lower temperatures below the region of glass transition," Wu said.

"These glass-forming metals have great promise in a variety of technical applications ranging from springs and sports products to military applications," Johnson said.

"Together with earlier published work on this topic, the new paper illustrates that atomic diffusion in these liquids is a very complex phenomenon involving more than one type of mechanism," he said. "The NMR work illustrates that atomic motion of beryllium atoms occurs by at least two different mechanisms."

Experiments designed by Johnson have been carried out on liquid alloys aboard two space shuttle flights. He also has patented a five-metal alloy that is stronger than steel or titanium and written about the materials' armor-piercing potential.

His alloy has been used to make golf club heads, for example, that drive golf balls longer and straighter than older clubs. The new club heads allow that because almost 100 percent of the energy involved is transferred to the ball rather than a lower percentage due to more energy being absorbed by standard metals.

The U.S. Army Research Office, National Science Foundation and the U.S. Department of Energy supported the research.


Story Source:

The above story is based on materials provided by University Of North Carolina At Chapel Hill. Note: Materials may be edited for content and length.


Cite This Page:

University Of North Carolina At Chapel Hill. "UNC-CH Physicists Find Atoms Of Chilled Metallic Liquids Chiefly Move In Lockstep." ScienceDaily. ScienceDaily, 12 November 1999. <www.sciencedaily.com/releases/1999/11/991112070246.htm>.
University Of North Carolina At Chapel Hill. (1999, November 12). UNC-CH Physicists Find Atoms Of Chilled Metallic Liquids Chiefly Move In Lockstep. ScienceDaily. Retrieved September 19, 2014 from www.sciencedaily.com/releases/1999/11/991112070246.htm
University Of North Carolina At Chapel Hill. "UNC-CH Physicists Find Atoms Of Chilled Metallic Liquids Chiefly Move In Lockstep." ScienceDaily. www.sciencedaily.com/releases/1999/11/991112070246.htm (accessed September 19, 2014).

Share This



More Matter & Energy News

Friday, September 19, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

MIT BioSuit A New Take On Traditional Spacesuits

MIT BioSuit A New Take On Traditional Spacesuits

Newsy (Sep. 19, 2014) The MIT BioSuit could be an alternative to big, bulky traditional spacesuits, but the concept needs some work. Video provided by Newsy
Powered by NewsLook.com
Virtual Reality Headsets Unveiled at Tokyo Game Show

Virtual Reality Headsets Unveiled at Tokyo Game Show

AFP (Sep. 18, 2014) Several companies unveiled virtual reality headsets at the Tokyo Game Show, Asia's largest digital entertainment exhibition. Duration: 00:48 Video provided by AFP
Powered by NewsLook.com
Apple's iOS8 Includes New 'Killswitch' To Curb Theft

Apple's iOS8 Includes New 'Killswitch' To Curb Theft

Newsy (Sep. 18, 2014) Apple's new operating system, iOS 8, comes with Apple's killswitch feature already activated, unlike all the models before it. Video provided by Newsy
Powered by NewsLook.com
Stocks Hit All-Time High as Fed Holds Steady

Stocks Hit All-Time High as Fed Holds Steady

AP (Sep. 17, 2014) The Federal Reserve signaled Wednesday that it plans to keep a key interest rate at a record low because a broad range of U.S. economic measures remain subpar. Stocks hit an all-time high on the news. (Sept. 17) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins