Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > Technique creates metal memory and could lead to vanishing dents

Abstract:
Crumpled kitchen foil that lays flat for reuse. Bent bumpers that straighten overnight. Dents in car doors that disappear when heated with a hairdryer. These and other physical feats may become possible with a technique to make memory metals discovered by researchers at the University of Illinois.

Technique creates metal memory and could lead to vanishing dents

CHAMPAIGN, IL | Posted on March 29th, 2007

Normally, when a piece of metal - such as a paperclip - is bent, the change in shape becomes permanent. But, when heat is added to bent metal films having the right microstructure, the researchers found, the films return to their original shapes. The higher the temperature, the sooner the metal films revert. "It's as though the metal has a memory of where it came from," said Taher A. Saif, a professor of mechanical science and engineering at Illinois, and senior author of a paper that describes the findings in the March 30 issue of the journal Science.

In the study, Saif and graduate students Jagannathan Rajagopalan and Jong H. Han explored aluminum films and gold films. The aluminum films were 200 nanometers thick, 50-60 microns wide and 300-360 microns long. The gold films were 200 nanometers thick, 12-20 microns wide and 185 microns long. The average grain size in the aluminum films was 65 nanometers; in the gold films, 50 nanometers.

"We found that the type of metal doesn't matter, said Saif, who also is a Willett Faculty Scholar and a researcher at the university's Micro and Nanotechnology Laboratory. "What matters is the size of the grains in the metal's crystalline microstructure, and a distribution in the size."

Grain sizes are typically one-third to one-half the thickness of a metal film. Raising the temperature by about 50 degrees Celsius causes the grains to grow larger.

If the grains are uniformly too small, the metal will be brittle and break while being bent. If the grains are uniformly too large, the metal will bend, but then stay in that position. To return to the initial shape, what's needed is a balance between brittleness and malleability.

That balance can be achieved through a combination of small and large grains, the researchers report.

Variations in the microstructure lead to plastic deformation in the larger grains and elastic accommodations in the smaller grains, Saif said. The bigger grains bend, but push and pull on the smaller grains, which become elastically deformed like a spring.

If the metal is then left alone, the smaller grains will release this energy and force the bigger grains back to their original shapes over time. This local release of energy can be speeded up by applying heat.

Controlling the crystalline microstructure of thin films also could reduce energy loss in oscillators and resonators used in electronic circuits, Saif said. Oscillators and resonators are found in products ranging from air bag sensors and camcorders to digital projectors and global positioning systems.

"If the grains that constitute the metal films in these devices are between 50 and 100 nanometers, they can be very lossy," Saif said. "However, if we decrease the grain size, we can reduce much of the energy loss."

The work was funded by the National Science Foundation.

####

For more information, please click here

Contacts:
James E. Kloeppel

217-244-1073

Copyright © University of Illinois at Urbana-Champaign

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

Discoveries

Heating quantum matter: A novel view on topology: Physicists demonstrate how heating up a quantum system can be used as a universal probe for exotic states of matter August 22nd, 2017

A Tougher Tooth: A new dental restoration composite developed by UCSB scientists proves more durable than the conventional material August 22nd, 2017

Nagoya physicists resolve long-standing mystery of structure-less transition: Nagoya University-led team of physicists use a synchrotron radiation X-ray source to probe a so-called 'structure-less' transition and develop a new understanding of molecular conductors August 21st, 2017

Tokai University research: Nanomaterial wrap for improved tissue imaging August 21st, 2017

Materials/Metamaterials

A Tougher Tooth: A new dental restoration composite developed by UCSB scientists proves more durable than the conventional material August 22nd, 2017

Silk could improve sensitivity, flexibility of wearable body sensors August 20th, 2017

Researchers printed graphene-like materials with inkjet August 17th, 2017

Two Scientists Receive Grants to Develop New Materials: Chad Mirkin and Monica Olvera de la Cruz recognized by Sherman Fairchild Foundation August 16th, 2017

Announcements

Heating quantum matter: A novel view on topology: Physicists demonstrate how heating up a quantum system can be used as a universal probe for exotic states of matter August 22nd, 2017

A Tougher Tooth: A new dental restoration composite developed by UCSB scientists proves more durable than the conventional material August 22nd, 2017

Nagoya physicists resolve long-standing mystery of structure-less transition: Nagoya University-led team of physicists use a synchrotron radiation X-ray source to probe a so-called 'structure-less' transition and develop a new understanding of molecular conductors August 21st, 2017

Tokai University research: Nanomaterial wrap for improved tissue imaging August 21st, 2017

Automotive/Transportation

2-faced 2-D material is a first at Rice: Rice University materials scientists create flat sandwich of sulfur, molybdenum and selenium August 14th, 2017

Engineers pioneer platinum shell formation process – and achieve first-ever observation August 11th, 2017

GLOBALFOUNDRIES, Silicon Mobility Deliver the Industry’s First Automotive FPCU to Boost Performance for Hybrid and Electric Vehicles: Silicon Mobility and GF’s 55nm LPx -enabled platform, with SST’s highly-reliable SuperFlash® memory technology, boosts automotive performance, ene August 3rd, 2017

Rice U. scientists map ways forward for lithium-ion batteries for extreme environments: Paper details developments toward high-temperature batteries July 27th, 2017

Human Interest/Art

Weizmann Institute of Science Presents: Weizmann Wonder Wander - 4G - is Online June 21st, 2016

Call for NanoArt and Art-Science-Technology Papers June 9th, 2016

Scientists propose non-animal tools for assessing the toxicity of nanomaterials: Particle and Fibre Toxicology publishes recommendations from expert group meeting April 26th, 2016

Are humans the new supercomputer?Today, people of all backgrounds can contribute to solving serious scientific problems by playing computer games. A Danish research group has extended the limits of quantum physics calculations and simultaneously blurred the boundaries between mac April 14th, 2016

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