Navigation Links
Brown University scientists discover new principle in material science
Date:4/7/2010

PROVIDENCE, R.I. [Brown University] 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.


'/>"/>

Contact: Richard Lewis
Richard_Lewis@brown.edu
401-863-3766
Brown University
Source:Eurekalert  

Related biology technology :

1. Silicon Kinetics Announces Addition of Dr. Rick Brown and Dr. Eric Topol to Its Board of Directors
2. Brown physicist discovers odd, fluctuating magnetic waves
3. Veteran Intellectual Property Team Joins Brown Rudnick
4. Brown engineering professor wins prestigious White House award
5. Marriott Resort Magically Turns Brown Grease "Green" With The Cost-Cutting Hydrologix GRS
6. TechConnect World Conference Showcases Houston Leaders May 3-7, at the George R. Brown Convention Center
7. TechConnect World Announces The CancerNano 2009 Symposium May 3-7, at the George R. Brown Convention Center in Houston
8. Brown chemists create more efficient palladium fuel cell catalysts
9. Jennifer Brownstein, of CONNEXION Healthcare, Honored as Rising Star by Healthcare Businesswomens Association
10. NSTI Announces the 12th Annual Nanotech Conference & Expo 2009 May 3-7, at the George R. Brown Convention Center in Houston, Texas
11. [video] David Brown, President and CEO of LifeVantage Corporation, Discusses Record Page Views on WallSt.nets 3-Minute Press Show
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Brown University scientists discover new principle in material science
(Date:6/27/2016)...  Sequenom, Inc. (NASDAQ: SQNM ), a ... the development of innovative products and services, announced today ... States denied its petition to review decisions ... U.S. Patent No. 6,258,540 (",540 Patent") are not patent ... Supreme Court,s Mayo Collaborative Services v. Prometheus Laboratories decision.  ...
(Date:6/27/2016)... PHILADELPHIA , June 27, 2016  Liquid ... today announced the funding of a Sponsored Research ... study circulating tumor cells (CTCs) from cancer patients.  ... changes in CTC levels correlate with clinical outcomes ... therapies. These data will then be employed to ...
(Date:6/24/2016)... ... ... Researchers at the Universita Politecnica delle Marche in Ancona combed medical journal articles ... findings are the subject of a new article on the Surviving Mesothelioma website. ... blood, lung fluid or tissue of mesothelioma patients that can help point doctors to ...
(Date:6/23/2016)... 2016 A person commits a crime, and the ... track the criminal down. An outbreak of foodborne ... Administration (FDA) uses DNA evidence to track down the bacteria ... far-fetched? It,s not. The FDA has increasingly used a complex, ... foodborne illnesses. Put as simply as possible, whole genome sequencing ...
Breaking Biology Technology:
(Date:6/3/2016)... June 3, 2016 ... Nepal hat ein ... hochsicherer geprägter Kennzeichen, einschließlich Personalisierung, Registrierung und ... der Produktion und Implementierung von Identitätsmanagementlösungen. Zahlreiche ... im Januar teilgenommen, aber Decatur wurde als ...
(Date:6/2/2016)... NEW YORK , June 2, 2016   The ... (Weather), is announcing Watson Ads, an industry-first capability in which ... advertising, by being able to ask questions via voice or ... Marketers have long ... with the consumer, that can be personal, relevant and valuable; ...
(Date:6/1/2016)... YORK , June 1, 2016 ... Technology in Election Administration and Criminal Identification to Boost ... to a recently released TechSci Research report, " Global ... By Region, Competition Forecast and Opportunities, 2011 - 2021", ... 24.8 billion by 2021, on account of growing security ...
Breaking Biology News(10 mins):