Featured Research

from universities, journals, and other organizations

Nanotechnology: Size-specific Cracking Shakes

Date:
August 5, 2008
Source:
DOE/Lawrence Livermore National Laboratory
Summary:
Certain sizes of nanostructures may be more susceptible to failure by fracture than others. As the size of a structure gets to the nanoscale, atomic vibrations (also known as phonons) begin to feel its size and shape in an effect called phonon confinement.

Scanning electron microscope images of a cerium hydride stacked-plate nanostructure. (a) Typical stacked-plate cluster. (b) Close-up view of the edges of the plates in (a). (c) Close-up view of another particle showing a finer fracture scale.
Credit: Image courtesy of DOE/Lawrence Livermore National Laboratory

Certain sizes of nanostructures may be more susceptible to failure by fracture than others.

That is the result of new research by LLNL’s Michael Manley and colleagues from Los Alamos National Laboratory that appears as a Rapid Communication in the journal Physical Review B, August 1.

As the size of a structure gets to the nanoscale, atomic vibrations (also known as phonons) begin to feel its size and shape in an effect called phonon confinement.

While these effects play an important role in thermal transport, electronic processes and thermodynamic stability, not much is known about their role in fracture.

However, in the new research, the scientists found that at a certain thickness, excess entropy of the confined vibrations reduces the fracture energy and results in a size-specific fracture.

Manley and the Los Alamos team found that particles formed during the reaction of cerium with hydrogen (cerium hydride) fractured into stacked plates. The plates exhibited two thickness scales, one at 100 nanometers, and an additional scale at 30-nanometer scale.

“When the fracture results in nanoplates, it leads to a low level of fracture energy at a certain size, resulting in a size-specific fracture,” Manley said. “This has important implications for the design of nanostructures.”

“It also may prove useful in the deliberate creation of large quantities of stable nanostructures,” he said.

Manley said the time scale for phonon excitations typically occurs in picoseconds, while crack growth is a slower process involving the simultaneous displacement of many planes of atoms over a relatively large distance compared to atomic vibrations. “Thus, the phonon confinement should occur instantaneously as the crack propagates,” he said.

Unlike with thermodynamic stability, fracture is a weak-link process, meaning that even a local weakening could be important in dictating the fracture process.

“This could have important consequences, not only for small materials, but also for the way cracks propagate in nanostructured bulk materials,” Manley said.


Story Source:

The above story is based on materials provided by DOE/Lawrence Livermore National Laboratory. Note: Materials may be edited for content and length.


Cite This Page:

DOE/Lawrence Livermore National Laboratory. "Nanotechnology: Size-specific Cracking Shakes." ScienceDaily. ScienceDaily, 5 August 2008. <www.sciencedaily.com/releases/2008/08/080801152147.htm>.
DOE/Lawrence Livermore National Laboratory. (2008, August 5). Nanotechnology: Size-specific Cracking Shakes. ScienceDaily. Retrieved September 21, 2014 from www.sciencedaily.com/releases/2008/08/080801152147.htm
DOE/Lawrence Livermore National Laboratory. "Nanotechnology: Size-specific Cracking Shakes." ScienceDaily. www.sciencedaily.com/releases/2008/08/080801152147.htm (accessed September 21, 2014).

Share This



More Matter & Energy News

Sunday, September 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Thousands March in NYC Over Climate Change

Thousands March in NYC Over Climate Change

AP (Sep. 21, 2014) — Accompanied by drumbeats, wearing costumes and carrying signs, thousands of demonstrators filled the streets of Manhattan and other cities around the world on Sunday to urge policy makers to take action on climate change. (Sept. 21) Video provided by AP
Powered by NewsLook.com
What This MIT Sensor Could Mean For The Future Of Robotics

What This MIT Sensor Could Mean For The Future Of Robotics

Newsy (Sep. 20, 2014) — MIT researchers developed a light-based sensor that gives robots 100 times the sensitivity of a human finger, allowing for "unprecedented dexterity." Video provided by Newsy
Powered by NewsLook.com
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
New Music With Recycled Instruments at Colombia Fest

New Music With Recycled Instruments at Colombia Fest

AFP (Sep. 19, 2014) — Jars, bottles, caps and even a pizza box, recovered from the trash, were the elements used by four musical groups at the "RSFEST2014 Sonorities Recycling Festival", in Colombian city of Cali. Duration: 00:49 Video provided by AFP
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