Featured Research

from universities, journals, and other organizations

Inspired by nature, researchers create tougher metal materials

Date:
July 2, 2014
Source:
North Carolina State University
Summary:
Drawing inspiration from the structure of bones and bamboo, researchers have found that by gradually changing the internal structure of metals they can make stronger, tougher materials that can be customized for a wide variety of applications -- from body armor to automobile parts.

This image illustrates the gradient structure concept.
Credit: Yuntian Zhu

Drawing inspiration from the structure of bones and bamboo, researchers have found that by gradually changing the internal structure of metals they can make stronger, tougher materials that can be customized for a wide variety of applications -- from body armor to automobile parts.

"If you looked at metal under a microscope you'd see that it is composed of millions of closely-packed grains," says Yuntian Zhu, a professor of materials science and engineering at NC State and senior author of two papers on the new work. "The size and disposition of those grains affect the metal's physical characteristics."

"Having small grains on the surface makes the metal harder, but also makes it less ductile -- meaning it can't be stretched very far without breaking," says Xiaolei Wu, a professor of materials science at the Chinese Academy of Sciences' Institute of Mechanics, and lead author of the two papers. "But if we gradually increase the size of the grains lower down in the material, we can make the metal more ductile. You see similar variation in the size and distribution of structures in a cross-section of bone or a bamboo stalk. In short, the gradual interface of the large and small grains makes the overall material stronger and more ductile, which is a combination of characteristics that is unattainable in conventional materials.

"We call this a 'gradient structure,' and you can use this technique to customize a metal's characteristics," Wu adds.

Wu and Zhu collaborated on research that tested the gradient structure concept in a variety of metals, including copper, iron, nickel and stainless steel. The technique improved the metal's properties in all of them.

The research team also tested the new approach in interstitial free (IF) steel, which is used in some industrial applications.

If conventional IF steel is made strong enough to withstand 450 megapascals (MPa) of stress, it has very low ductility -- the steel can only be stretched to less than 5 percent of its length without breaking. That makes it unsafe. Low ductility means a material is susceptible to catastrophic failure, such as suddenly snapping in half. Highly ductile materials can stretch, meaning they're more likely to give people time to respond to a problem before total failure.

By comparison, the researchers created an IF steel with a gradient structure; it was strong enough to handle 500 MPa and ductile enough to stretch to 20 percent of its length before failing.

The researchers are also interested in using the gradient structure approach to make materials more resistant to corrosion, wear and fatigue.

"We think this is an exciting new area for materials research because it has a host of applications and it can be easily and inexpensively incorporated into industrial processes," Wu says.


Story Source:

The above story is based on materials provided by North Carolina State University. Note: Materials may be edited for content and length.


Journal References:

  1. X. L. Wu, P. Jiang, L. Chen, J. F. Zhang, F. P. Yuan, Y. T. Zhu. Synergetic Strengthening by Gradient Structure. Materials Research Letters, 2014; 1 DOI: 10.1080/21663831.2014.935821
  2. X. Wu, P. Jiang, L. Chen, F. Yuan, Y. T. Zhu. Extraordinary strain hardening by gradient structure. Proceedings of the National Academy of Sciences, 2014; 111 (20): 7197 DOI: 10.1073/pnas.1324069111

Cite This Page:

North Carolina State University. "Inspired by nature, researchers create tougher metal materials." ScienceDaily. ScienceDaily, 2 July 2014. <www.sciencedaily.com/releases/2014/07/140702122434.htm>.
North Carolina State University. (2014, July 2). Inspired by nature, researchers create tougher metal materials. ScienceDaily. Retrieved October 23, 2014 from www.sciencedaily.com/releases/2014/07/140702122434.htm
North Carolina State University. "Inspired by nature, researchers create tougher metal materials." ScienceDaily. www.sciencedaily.com/releases/2014/07/140702122434.htm (accessed October 23, 2014).

Share This



More Matter & Energy News

Thursday, October 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

3D Printed Instruments Make Sweet Music in Sweden

3D Printed Instruments Make Sweet Music in Sweden

Reuters - Innovations Video Online (Oct. 23, 2014) — Students from Lund University's Malmo Academy of Music are believed to be the world's first band to all use 3D printed instruments. The guitar, bass guitar, keyboard and drums were built by Olaf Diegel, professor of product development, who says 3D printing allows musicians to design an instrument to their exact specifications. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com
Chameleon Camouflage to Give Tanks Cloaking Capabilities

Chameleon Camouflage to Give Tanks Cloaking Capabilities

Reuters - Innovations Video Online (Oct. 22, 2014) — Inspired by the way a chameleon changes its colour to disguise itself; scientists in Poland want to replace traditional camouflage paint with thousands of electrochromic plates that will continuously change colour to blend with its surroundings. The first PL-01 concept tank prototype will be tested within a few years, with scientists predicting that a similar technology could even be woven into the fabric of a soldiers' clothing making them virtually invisible to the naked eye. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com
Jet Sales Lift Boeing Profit 18 Pct.

Jet Sales Lift Boeing Profit 18 Pct.

Reuters - Business Video Online (Oct. 22, 2014) — Strong jet demand has pushed Boeing to raise its profit forecast for the third time, but analysts were disappointed by its small cash flow. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
Internet of Things Aims to Smarten Your Life

Internet of Things Aims to Smarten Your Life

AP (Oct. 22, 2014) — As more and more Bluetooth-enabled devices are reaching consumers, developers are busy connecting them together as part of the Internet of Things. (Oct. 22) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins