by Staff Writers
Hamburg, Germany (SPX) Jun 13, 2011
A world premiere: a material which changes its strength, virtually at the touch of a button. This transformation can be achieved in a matter of seconds through changes in the electron structure of a material; thus hard and brittle matter, for example, can become soft and malleable. What makes this development revolutionary, is that the transformation can be controlled by electric signals.
This world-first has its origins in Hamburg. Jorg WeiBmuller, a materials scientist at both the Technical University of Hamburg and the Helmholtz Center Geesthacht, has carried out research on this groundbreaking development, working in cooperation with colleagues from the Institute for Metal Research in Shenyang, China.
The 51-year-old researcher from the Saarland referred to his fundamental research, which opens the door to a multitude of diverse applications, as "a breakthrough in the material sciences". The new metallic high-performance material is described by Prof. Dr. Jorg WeiBmuller and the Chinese research scientist Hai-Jun Jin in the latest issue of the renowned scientific journal "Science" (DOI: 10.1126/science.1202190). Their research findings could, for example, make future intelligent materials with the ability of self healing, smoothing out flaws autonomously.
The firmness of a boiled egg can be adjusted at will through the cooking time. Some decisions are, however, irrevocable - a hard-boiled egg can never be reconverted into a soft-boiled one. There would be less annoyance at the breakfast table if we could simply switch back and forth between the different degrees of firmness of the egg.
Similar issues arise in the making of structural materials such as metals and alloys. The materials properties are set once and for all during production. This forces engineers to make compromises in the selection of the mechanical properties of a material. Greater strength is inevitably accompanied by increased brittleness and a reduction of the damage tolerance.
Professor WeiBmuller, head of the Institute of Materials Physics and Technology at the Technical University of Hamburg and also of the department for Hybrid Material Systems at the Helmholtz Center Geesthacht, stated: "This is a point where significant progress is being made.
For the first time we have succeeded in producing a material which, while in service, can switch back and forth between a state of strong and brittle behavior and one of soft and malleable. We are still at the fundamental research stage but our discovery may bring significant progress in the development of so-called smart materials."
A Marriage of Metal and Water
The pores are impregnated with a conductive liquid, for example a simple saline solution or a diluted acid, and a true hybrid material of metal and liquid is thus created. It is the unusual "marriage", as WeiBmuller calls this union of metal and water which, when triggered by an electric signal, enables the properties of the material to change at the touch of a button.
As ions are dissolved in the liquid, the surfaces of the metal can be electrically charged. In other words, the mechanical properties of the metallic partner are changed by the application of an electric potential in the liquid partner. The effect can be traced back to a strengthening or weakening of the atomic bonding in the surface of the metal when extra electrons are added to or withdrawn from the surface atoms.
The strength of the material can be as much as doubled when required. Alternatively, the material can be switched to a state which is weaker, but more damage tolerant, energy-absorbing and malleable.
Specific applications are still a matter for the future. However, researchers are already thinking ahead. In principle, the material can create electric signals spontaneously and selectively, so as to strengthen the matter in regions of local stress concentration. Damage, for instance in the form of cracks, could thereby be prevented or even healed. This has brought scientists a great step closer to their objective of 'intelligent' high performance materials.
Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.
Chinalco sets up rare earths processing firm
Beijing (AFP) June 8, 2011
Chinalco, China's largest alumina producer, has set up a company in the country's east that will separate highly profitable rare earths from crude ores, a spokesman said Wednesday. The company, a joint venture in Jiangsu province, was launched on Tuesday, Chinalco spokesman Yuan Li told AFP. Chinalco said in a statement Wednesday that the company, launched with five firms in Jiangsu that ... read more
|The content herein, unless otherwise known to be public domain, are Copyright 1995-2011 - Space Media Network. AFP and UPI Wire Stories are copyright Agence France-Presse and United Press International. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement|