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:2/4/2016)... Feb. 4, 2016  CytoSorbents Corporation (NASDAQ: ... its flagship CytoSorb® blood filter to treat deadly ... the world, announced that CEO Dr. Phillip ... Source Capital Group,s 2016 Disruptive Growth & Healthcare ... company.  Conference Presentation Details: ...
(Date:2/4/2016)... -- ContraVir Pharmaceuticals, Inc. (NASDAQ: CTRV ), a ... targeted antiviral therapies, announced today that it will present ... held February 8-9, 2016, at the Waldorf Astoria New ... Healthcare Conference, taking place in New York ... Sapirstein , Chief Executive Officer of ContraVir, will provide ...
(Date:2/4/2016)... ... 04, 2016 , ... Franz Inc. , an early ... has been recognized As “ Best in Semantic Web Technology - USA & ... America, it’s our priority to showcase prominent professionals who are excelling in their ...
(Date:2/3/2016)... SAN DIEGO , Feb. 3, 2016 /PRNewswire/ ... medicine company with the first pluripotent stem cell-derived ... 1 diabetes in clinical-stage development, today announced that ... Janssen Pharmaceutical Companies of Johnson & Johnson, have ... BetaLogics group into ViaCyte.  The agreement provides ViaCyte ...
Breaking Biology Technology:
(Date:1/21/2016)... , January 21, 2016 ... to a new market research report "Emotion Detection and ... Others), Software Tools (Facial Expression, Voice Recognition and ... - Global forecast to 2020", published by MarketsandMarkets, ... expected to reach USD 22.65 Billion by 2020, ...
(Date:1/18/2016)... Calif. , Jan. 18, 2016  Extenua ... software that simplifies the use and access of ... and go-to-market partnership with American Cyber.  ... brings extensive experience leading transformational C4ISR and Cyber ... and integrating the latest proven technology solutions," said ...
(Date:1/11/2016)... 11, 2016 Synaptics Incorporated (NASDAQ: SYNA ... announced that its ClearPad ® TouchView ™ ... two separate categories in the 8 th Annual ... Technology Breakthrough. The Synaptics ® TDDI solution enables ... chain, thinner devices, brighter displays and borderless designs. ...
Breaking Biology News(10 mins):