Nanotechnology Now

Our NanoNews Digest Sponsors
Heifer International



Home > Press > Kinks and curves at the nanoscale: New research shows 'perfect twin boundaries' are not so perfect

Since 2004, materials scientists and nanotechnologists have been excited about a special of arrangement of atoms called a "coherent twin boundary" that can add strength and other advantages to metals like gold and copper. The CTB's are often described as "perfect," appearing like a one-atom-thick perfectly-flat plane in models and images. New research at the University of Vermont and Lawrence Livermore National Laboratory shows that these boundaries are not so perfect after all. Even more surprising, the newly discovered kinks and defects appear to be the cause of the CTB's strength.This image shows a simulation of atoms in a coherent twin boundary (shown in red) in copper. The newly discovered "kink" defects appear as green step-like structures and folds in the red areas. The red twin boundaries extend between columns of green atoms which represent grain boundaries within the copper.

Credit: Frederic Sansoz, University of Vermont
Since 2004, materials scientists and nanotechnologists have been excited about a special of arrangement of atoms called a "coherent twin boundary" that can add strength and other advantages to metals like gold and copper. The CTB's are often described as "perfect," appearing like a one-atom-thick perfectly-flat plane in models and images. New research at the University of Vermont and Lawrence Livermore National Laboratory shows that these boundaries are not so perfect after all. Even more surprising, the newly discovered kinks and defects appear to be the cause of the CTB's strength.This image shows a simulation of atoms in a coherent twin boundary (shown in red) in copper. The newly discovered "kink" defects appear as green step-like structures and folds in the red areas. The red twin boundaries extend between columns of green atoms which represent grain boundaries within the copper.

Credit: Frederic Sansoz, University of Vermont

Abstract:
One of the basic principles of nanotechnology is that when you make things extremely small—one nanometer is about five atoms wide, 100,000 times smaller than the diameter of a human hair—they are going to become more perfect.

Kinks and curves at the nanoscale: New research shows 'perfect twin boundaries' are not so perfect

Burlington, VT | Posted on May 20th, 2013

"Perfect in the sense that their arrangement of atoms in the real world will become more like an idealized model," says University of Vermont engineer Frederic Sansoz, "with smaller crystals—in for example, gold or copper—it's easier to have fewer defects in them."

And eliminating the defects at the interface separating two crystals, or grains, has been shown by nanotechnology experts to be a powerful strategy for making materials stronger, more easily molded, and less electrically resistant—or a host of other qualities sought by designers and manufacturers.

Since 2004, when a seminal paper came out in Science, materials scientists have been excited about one special of arrangement of atoms in metals and other materials called a "coherent twin boundary" or CTB.

Based on theory and experiment, these coherent twin boundaries are often described as "perfect," appearing like a perfectly flat, one-atom-thick plane in computer models and electron microscope images.

Over the last decade, a body of literature has shown these coherent twin boundaries—found at the nanoscale within the crystalline structure of common metals like gold, silver and copper—are highly effective at making materials much stronger while maintaining their ability to undergo permanent change in shape without breaking and still allowing easy transmission of electrons—an important fact for computer manufacturing and other electronics applications.

But new research now shows that coherent twin boundaries are not so perfect after all.

A team of scientists, including Sansoz, a professor in UVM's College of Engineering and Mathematical Sciences, and colleagues from the Lawrence Livermore National Laboratory and elsewhere, write in the May 19 edition of Nature Materials that coherent twin boundaries found in copper "are inherently defective."

With a high-resolution electron microscope, using a more powerful technique than has ever been used to examine these boundaries, they found tiny kink-like steps and curvatures in what had previously been observed as perfect.

Even more surprising, these kinks and other defects appear to be the cause of the coherent twin boundary's strength and other desirable qualities.

"Everything we have learned on these materials in the past 10 years will have to be revisited with this new information," Sansoz says

The experiment, led by Morris Wang at the Lawrence Livermore Lab, applied a newly developed mapping technique to study the crystal orientation of CTBs in so-called nanotwinned copper and "boom—it revealed these defects," says Sansoz.

This real-world discovery conformed to earlier intriguing theoretical findings that Sansoz had been making with "atomistic simulations" on a computer. The lab results sent Sansoz back to his computer models where he introduced the newly discovered "kink" defects into his calculations. Using UVM's Vermont Advanced Computing Center, he theoretically confirmed that the kink defects observed by the Livermore team lead to "rather rich deformation processes at the atomic scale," he says, that do not exist with perfect twin boundaries.

With the computer model, "we found a series of completely new mechanisms," he says, for explaining why coherent twin boundaries simultaneously add strength and yet also allow stretching (what scientists call "tensile ductility")— properties that are usually mutually exclusive in conventional materials.

"We had no idea such defects existed," says Sansoz. "So much for the perfect twin boundary. We now call them defective twin boundaries."

For several decades, scientists have looked for ways to shrink the size of individual crystalline grains within metals and other materials. Like a series of dykes or walls within the larger structure, the boundaries between grains can slow internal slip and help resist failure. Generally, the more of these boundaries—the stronger the material.

Originally, scientists believed that coherent twin boundaries in materials were much more reliable and stable than conventional grain boundaries, which are incoherently full of defects. But the new research shows they could both contain similar types of defects despite very different boundary energies.

"Understanding these defective structures is the first step to take full use of these CTBs for strengthening and maintaining the ductility and electrical conductivity of many materials," Morris Wang said. "To understand the behavior and mechanisms of these defects will help our engineering design of these materials for high-strength applications."

For Sansoz, this discovery underlines a deep principle, "There are all manner of defects in nature," he says, "with nanotech, you are trying to control the way they are formed and dispersed in matter, and to understand their impact on properties. The point of this paper is that some defects make a material stronger."

####

For more information, please click here

Contacts:
Joshua Brown

802-656-3039

Copyright © University of Vermont

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

New class of protein misfolding simulated in high definition: Evidence for recently identified and long-lasting type of protein misfolding bolstered by atomic-scale simulations and new experiments August 8th, 2025

Sensors innovations for smart lithium-based batteries: advancements, opportunities, and potential challenges August 8th, 2025

Deciphering local microstrain-induced optimization of asymmetric Fe single atomic sites for efficient oxygen reduction August 8th, 2025

Lab to industry: InSe wafer-scale breakthrough for future electronics August 8th, 2025

Imaging

ICFO researchers overcome long-standing bottleneck in single photon detection with twisted 2D materials August 8th, 2025

Simple algorithm paired with standard imaging tool could predict failure in lithium metal batteries August 8th, 2025

First real-time observation of two-dimensional melting process: Researchers at Mainz University unveil new insights into magnetic vortex structures August 8th, 2025

Physics

INRS and ELI deepen strategic partnership to train the next generation in laser science:PhD students will benefit from international mobility and privileged access to cutting-edge infrastructure June 6th, 2025

Quantum computers simulate fundamental physics: shedding light on the building blocks of nature June 6th, 2025

A 1960s idea inspires NBI researchers to study hitherto inaccessible quantum states June 6th, 2025

Magnetism in new exotic material opens the way for robust quantum computers June 4th, 2025

Laboratories

Giving batteries a longer life with the Advanced Photon Source: New research uncovers a hydrogen-centered mechanism that triggers degradation in the lithium-ion batteries that power electric vehicles September 13th, 2024

A 2D device for quantum cooling:EPFL engineers have created a device that can efficiently convert heat into electrical voltage at temperatures lower than that of outer space. The innovation could help overcome a significant obstacle to the advancement of quantum computing technol July 5th, 2024

A battery’s hopping ions remember where they’ve been: Seen in atomic detail, the seemingly smooth flow of ions through a battery’s electrolyte is surprisingly complicated February 16th, 2024

NRL discovers two-dimensional waveguides February 16th, 2024

Govt.-Legislation/Regulation/Funding/Policy

New imaging approach transforms study of bacterial biofilms August 8th, 2025

INRS and ELI deepen strategic partnership to train the next generation in laser science:PhD students will benefit from international mobility and privileged access to cutting-edge infrastructure June 6th, 2025

Electrifying results shed light on graphene foam as a potential material for lab grown cartilage June 6th, 2025

Institute for Nanoscience hosts annual proposal planning meeting May 16th, 2025

Discoveries

Deciphering local microstrain-induced optimization of asymmetric Fe single atomic sites for efficient oxygen reduction August 8th, 2025

ICFO researchers overcome long-standing bottleneck in single photon detection with twisted 2D materials August 8th, 2025

New molecular technology targets tumors and simultaneously silences two ‘undruggable’ cancer genes August 8th, 2025

Simple algorithm paired with standard imaging tool could predict failure in lithium metal batteries August 8th, 2025

Materials/Metamaterials/Magnetoresistance

First real-time observation of two-dimensional melting process: Researchers at Mainz University unveil new insights into magnetic vortex structures August 8th, 2025

Researchers unveil a groundbreaking clay-based solution to capture carbon dioxide and combat climate change June 6th, 2025

A 1960s idea inspires NBI researchers to study hitherto inaccessible quantum states June 6th, 2025

Institute for Nanoscience hosts annual proposal planning meeting May 16th, 2025

Announcements

Sensors innovations for smart lithium-based batteries: advancements, opportunities, and potential challenges August 8th, 2025

Deciphering local microstrain-induced optimization of asymmetric Fe single atomic sites for efficient oxygen reduction August 8th, 2025

Japan launches fully domestically produced quantum computer: Expo visitors to experience quantum computing firsthand August 8th, 2025

ICFO researchers overcome long-standing bottleneck in single photon detection with twisted 2D materials August 8th, 2025

Tools

Japan launches fully domestically produced quantum computer: Expo visitors to experience quantum computing firsthand August 8th, 2025

Portable Raman analyzer detects hydrogen leaks from a distance: Device senses tiny concentration changes of hydrogen in ambient air, offering a dependable way to detect and locate leaks in pipelines and industrial systems April 25th, 2025

Rice researchers harness gravity to create low-cost device for rapid cell analysis February 28th, 2025

New 2D multifractal tools delve into Pollock's expressionism January 17th, 2025

Research partnerships

Lab to industry: InSe wafer-scale breakthrough for future electronics August 8th, 2025

INRS and ELI deepen strategic partnership to train the next generation in laser science:PhD students will benefit from international mobility and privileged access to cutting-edge infrastructure June 6th, 2025

Superconductors: Amazingly orderly disorder: A surprising effect was discovered through a collaborative effort by researchers from TU Wien and institutions in Croatia, France, Poland, Singapore, Switzerland, and the US during the investigation of a special material: the atoms are May 14th, 2025

HKU physicists uncover hidden order in the quantum world through deconfined quantum critical points April 25th, 2025

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




  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project