Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > Brown University Scientists Discover New Principle in Material Science

Atomic Strength: A material science team led by Brown University engineers has found that the deformation of nanotwinned metals is characterized by the motion of highly ordered, necklace-like patterns of crystal defects called dislocations. Credit: Huajian Gao and Xiaoyan Li/Brown University
Atomic Strength: A material science team led by Brown University engineers has found that the deformation of nanotwinned metals is characterized by the motion of highly ordered, necklace-like patterns of crystal defects called dislocations. Credit: Huajian Gao and Xiaoyan Li/Brown University

Abstract:
A material science team led by Brown University engineers has found that the deformation of nanotwinned metals is characterized by the motion of highly ordered, necklace-like patterns of crystal defects called dislocations.

Brown University Scientists Discover New Principle in Material Science

Providence, RI | Posted on April 8th, 2010

Materials scientists have known that a metal's strength (or weakness) is governed by dislocation interactions, a messy exchange of intersecting fault lines that move or ripple within metallic crystals. But what happens when metals are engineered at the nanoscale? Is there a way to make metals stronger and more ductile by manipulating their nanostructures?

Brown University scientists may have figured out a way. In a paper published in Nature, Huajian Gao and researchers from the University of Alabama and China report a new mechanism that governs the peak strength of nanostructured metals. By performing 3-D atomic simulations of divided grains of nanostructured metals, Gao and his team observed that dislocations organize themselves in highly ordered, necklace-like patterns throughout the material. The nucleation of this dislocation pattern is what determines the peak strength of materials, the researchers report.

The finding could open the door to producing stronger, more ductile metals, said Gao, professor of engineering at Brown. "This is a new theory governing strength in materials science," he added. "Its significance is that it reveals a new mechanism of material strength that is unique for nanostructured materials."

Divide a grain of metal using a specialized technique, and the pieces may reveal boundaries within the grain that scientists refer to as twin boundaries. These are generally flat, crystal surfaces that mirror the crystal orientations across them. The Chinese authors created nanotwinned boundaries in copper and were analyzing the space between the boundaries when they made an interesting observation: The copper got stronger as the space between the boundaries decreased from 100 nanometers, ultimately reaching a peak of strength at 15 nanometers. However, as the spacing decreased from 15 nanometers, the metal got weaker.

"This is very puzzling," Gao said.

So Gao and Brown graduate student Xiaoyan Li dug a little further. The Brown scientists reproduced their collaborators' experiment in computer simulations involving 140 million atoms. They used a supercomputer at the National Institute for Computational Sciences in Tennessee, which allowed them to analyze the twin boundaries at the atomic scale. To their surprise, they saw an entirely new phenomenon: A highly ordered dislocation pattern controlled by nucleation had taken hold and dictated the copper's strength. The pattern was characterized by groups of atoms near the dislocation core and assembled in highly ordered, necklace-like patterns.

"They're not getting in each other's way. They're very organized," Gao said.

From the experiments and the computer modeling, the researchers theorize that at the nanoscale, dislocation nucleation can become the governing principle to determining a metal's strength or weakness. The authors presented a new equation in the Nature paper to describe the principle.

"Our work provides a concrete example of a source-controlled deformation mechanism in nanostructured materials for the first time and, as such, can be expected to have a profound impact on the field of materials science," Gao said.

The other researchers who contributed to the paper are Yujie Wei from the University of Alabama and Ke Lu and Lei Lu from the Chinese Academy of Sciences. The U.S. National Science Foundation, the National Science Foundation in China and the Ministry of Science and Technology in China funded the research.

####

For more information, please click here

Contacts:
Richard Lewis
(401) 863-3766

Copyright © Brown University

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

Two-dimensional melting of hard spheres experimentally unravelled after 60 years: First definitive experimental evidence of two-dimensional melting of hard spheres April 21st, 2017

National Conference on Nanomaterials, (NCN-2017) April 21st, 2017

NanoMONITOR shares its latest developments concerning the NanoMONITOR Software and the Monitoring stations April 21st, 2017

Nanomechanics, Inc. Unveils New Product at ICMCTF Show April 25th: Nanoindentation experts will launch the new Gemini that measures the interaction of two objects that are sliding across each other – not merely making contact April 21st, 2017

Govt.-Legislation/Regulation/Funding/Policy

NanoMONITOR shares its latest developments concerning the NanoMONITOR Software and the Monitoring stations April 21st, 2017

Better living through pressure: Functional nanomaterials made easy April 19th, 2017

Nano-SPEARs gently measure electrical signals in small animals: Rice University's tiny needles simplify data gathering to probe diseases, test drugs April 17th, 2017

Emergency Use Authorization for Gene-RADAR® Zika Virus Test: FDA Authorization for the Gene-RADAR® Zika Virus Test on the XPRIZE-Winning Gene-RADAR® Platform April 14th, 2017

Possible Futures

Two-dimensional melting of hard spheres experimentally unravelled after 60 years: First definitive experimental evidence of two-dimensional melting of hard spheres April 21st, 2017

Rice crew revved for Nanocar Race: Nanocar creator James Tour and team take on international competition with single-molecule marvel April 20th, 2017

Making Batteries From Waste Glass Bottles: UCR researchers are turning glass bottles into high performance lithium-ion batteries for electric vehicles and personal electronics April 19th, 2017

Better living through pressure: Functional nanomaterials made easy April 19th, 2017

Academic/Education

SUNY Polytechnic Institute Announces Total of 172 Teams Selected to Compete in Solar in Your Community Challenge: Teams from 40 states, plus Washington, DC, 2 Territories, and 4 American Indian Reservations, Will Deploy Solar in Underserved Communities April 20th, 2017

Rice crew revved for Nanocar Race: Nanocar creator James Tour and team take on international competition with single-molecule marvel April 20th, 2017

The Catholic University of Rome uses the JPK NanoWizard® AFM & CellHesion® systems to understand how cells sense and respond to mechanical stimuli April 5th, 2017

AIM Photonics Welcomes Coventor as Newest Member: US-Backed Initiative Taps Process Modeling Specialist to Enable Manufacturing of High-Yield, High-Performance Integrated Photonic Designs March 16th, 2017

Discoveries

Two-dimensional melting of hard spheres experimentally unravelled after 60 years: First definitive experimental evidence of two-dimensional melting of hard spheres April 21st, 2017

Wood filter removes toxic dye from water April 21st, 2017

Rice crew revved for Nanocar Race: Nanocar creator James Tour and team take on international competition with single-molecule marvel April 20th, 2017

Better living through pressure: Functional nanomaterials made easy April 19th, 2017

Materials/Metamaterials

Two-dimensional melting of hard spheres experimentally unravelled after 60 years: First definitive experimental evidence of two-dimensional melting of hard spheres April 21st, 2017

National Conference on Nanomaterials, (NCN-2017) April 21st, 2017

Forge Nano 2017: 1st Quarter Media Update April 20th, 2017

Making Batteries From Waste Glass Bottles: UCR researchers are turning glass bottles into high performance lithium-ion batteries for electric vehicles and personal electronics April 19th, 2017

Announcements

Two-dimensional melting of hard spheres experimentally unravelled after 60 years: First definitive experimental evidence of two-dimensional melting of hard spheres April 21st, 2017

National Conference on Nanomaterials, (NCN-2017) April 21st, 2017

NanoMONITOR shares its latest developments concerning the NanoMONITOR Software and the Monitoring stations April 21st, 2017

Nanomechanics, Inc. Unveils New Product at ICMCTF Show April 25th: Nanoindentation experts will launch the new Gemini that measures the interaction of two objects that are sliding across each other – not merely making contact April 21st, 2017

Research partnerships

Better living through pressure: Functional nanomaterials made easy April 19th, 2017

Shedding light on the absorption of light by titanium dioxide April 14th, 2017

AIM Photonics Presents Cutting-Edge Integrated Photonics Technology Developments to Packed House at OFC 2017, the Optical Networking and Communication Conference & Exhibition April 11th, 2017

Nanoparticles open new window for biological imaging: “Quantum dots” that emit infrared light enable highly detailed images of internal body structures April 10th, 2017

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