Nanotechnology Now

Our NanoNews Digest Sponsors


Heifer International

Wikipedia Affiliate Button

Home > Press > Size-specific cracking shakes out at the nanoscale

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.
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.

Abstract:
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.

Size-specific cracking shakes out at the nanoscale

LIVERMORE, CA | Posted on July 31st, 2008

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.

The research appears in the Aug. 1 online issue of Physical Review B.

####

About Lawrence Livermore National Laboratory
Founded in 1952, Lawrence Livermore National Laboratory is a national security laboratory with a mission to ensure national security and apply science and technology to the important issues of our time. Lawrence Livermore National Laboratory is managed by Lawrence Livermore National Security, LLC for the U.S. Department of Energy's National Nuclear Security Administration.

For more information, please click here

Contacts:
Anne M. Stark
Phone: (925) 422-9799

Copyright © Lawrence Livermore National Laboratory

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Scientists change properties of zeolites to improve hemodialysis July 29th, 2016

Novel state of matter: Observation of a quantum spin liquid July 29th, 2016

A new type of quantum bits July 29th, 2016

Lonely atoms, happily reunited July 29th, 2016

Laboratories

New nontoxic process promises larger ultrathin sheets of 2-D nanomaterials July 27th, 2016

New lithium-oxygen battery greatly improves energy efficiency, longevity: New chemistry could overcome key drawbacks of lithium-air batteries July 26th, 2016

An accelerated pipeline to open materials research: ORNL workflow system unites imaging, algorithms, and HPC to advance materials discovery and design July 24th, 2016

Scientists develop way to upsize nanostructures into light, flexible 3-D printed materials: Virginia Tech, Livermore National Lab researchers develop hierarchical 3-D printed metallic materials July 20th, 2016

Discoveries

Scientists change properties of zeolites to improve hemodialysis July 29th, 2016

Novel state of matter: Observation of a quantum spin liquid July 29th, 2016

A new type of quantum bits July 29th, 2016

Lonely atoms, happily reunited July 29th, 2016

Materials/Metamaterials

Scientists change properties of zeolites to improve hemodialysis July 29th, 2016

Lonely atoms, happily reunited July 29th, 2016

WSU researchers 'watch' crystal structure change in real time: Breakthrough made possible by new Argonne facility July 27th, 2016

New lithium-oxygen battery greatly improves energy efficiency, longevity: New chemistry could overcome key drawbacks of lithium-air batteries July 26th, 2016

Announcements

Scientists change properties of zeolites to improve hemodialysis July 29th, 2016

Novel state of matter: Observation of a quantum spin liquid July 29th, 2016

A new type of quantum bits July 29th, 2016

Lonely atoms, happily reunited July 29th, 2016

NanoNews-Digest
The latest news from around the world, FREE




  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project







Car Brands
Buy website traffic