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:4/27/2016)... PARIS , April 27, 2016 ... system disorders, today announces the appointment of Catherine Moukheibir as ... succeed MedDay,s previous Chairman, Jean Jacques Garaud , who ... The change is effective immediately. Catherine started her ... Boston and London .  She ...
(Date:4/26/2016)... ... April 26, 2016 , ... The European Patent ... selected as one of three finalists for the European Inventor Award 2016 in the ... prize will be announced at a ceremony in Lisbon on June 9th. , The ...
(Date:4/26/2016)... ... April 26, 2016 , ... BioFactura, Inc ., a ... round of financing. Healthy investor interest drove significant oversubscription of the original $1.5M ... known as biosimilars, to the advanced preclinical stages. , Chief Executive Officer and President, ...
(Date:4/26/2016)... ... April 26, 2016 , ... The Institute for Venture Science ... of pre-proposal competition for scientific grants. , The IVS funds promising ideas that ... highest potential to replace paradigms that have outlived their usefulness. All areas of ...
Breaking Biology Technology:
(Date:3/9/2016)... Germany , March 9, 2016 ... country,s government identified that more than 23,000 public service ... or had been receiving their salary unlawfully.    ... African country,s government identified that more than 23,000 public ... name or had been receiving their salary unlawfully.    ...
(Date:3/3/2016)... March 3, 2016  FlexTech, a SEMI Strategic Association ... Innovation, Research & Development, Leadership in Education, and, in ... the 9 th year of the FLEXI Awards ... and individuals from past years . Judging was ... pre-described set of criteria, by a panel of non-affiliated, ...
(Date:3/2/2016)... DUBLIN , March 2, 2016 /PRNewswire/ ... has announced the addition of the  "Global ... to their offering.  ,     (Logo: http://photos.prnewswire.com/prnh/20130307/600769) , ... sector to grow at a CAGR of ... http://www.researchandmarkets.com/research/wzwqtz/global_biometrics ) has announced the addition ...
Breaking Biology News(10 mins):