Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Simulation-based matchmaking for Shape Memory Alloys

01.07.2010
RUB-researchers discover Shape-Memory Metals with unprecedented functional stability / Cover story in „Advanced Functional Materials“

A new shape memory alloy with up to now unprecedented functional stability was developed by researchers from the Institute for Materials at the Ruhr-Universität Bochum in cooperation with researchers from the USA and Japan. Based on a theoretical prediction, they used combinatorial materials science methods, i.e. so-called materials libraries, for a targeted search of optimized alloy compositions. The result consists of four components: titanium, nickel, copper and palladium.

From the new material, the researchers expect a stable shape memory effect and improved lifetime, e.g. for applications in medical devices such as stents. The scientists report their results in the noted journal “Advanced Functional Materials”, which selected their contribution as cover story.

Shape memory alloys

Shape memory alloys (SMAs) are materials that after being deformed mechanically can return to their original shape upon heating (shape memory effect) and/or allow for “elastic” strains up to 10 % (superelasticity). Those remarkable effects are based on a reversible martensitic phase transformation: a change in the crystal lattice as a function of temperature or stress. However, such changes do not leave the material untouched. Defects are formed during cyclic deformations, which accumulate and lead to decreasing shape memory properties. “The defects originate from the interface between the high-temperature phase (austenite) and the low-temperature phase (martensite) as a result of the crystallographic incompatibility”, explains Robert Zarnetta from the Materials Research Department at the RUB.

Four matching partners

Theoretical calculations from the co-workers in the USA predicted that the incompatibility can vanish for alloys with special lattice parameters, such that the high-temperature and the low-temperature phase are compatible. As optimal partners for such an alloy, titanium, nickel, copper and palladium were identified by theory. The successful experimental “matchmaking” was realized by using thin film materials libraries, which enabled the screening of a large portion of the four component (quaternary) composition space using dedicated high-throughput characterization tools. “To find or optimize the special composition in the quaternary alloy system using conventional methods would have been extremely challenging”, explains Prof. Dr. Alfred Ludwig (Chair Materials for Microtechnology) and thus highlights the advantage of the combinatorial materials science approach.

Compatible crystal lattices promote stability

Next to the discovery of the special alloy composition, the scientists also determined the underlying composition-structure-property relationship, which was subsequently used to successfully transfer the thin film results to bulk material. Thus, the fundamental relation between the crystal structure of a shape memory alloy and its functional stability could be proven for the first time. “An improved compatibility of the high- and low-temperature crystal lattice results in improved functional stability” summarized Robert Zarnetta , going on to explain “that this relation could only be discovered by bridging the fields of combinatorial SMA thin film and the conventional bulk materials development”.

Collaborative Research Center and Research Department

The results were conducted, based on the work within the collaborative research center “SFB 459”, at the Chairs “Materials for Microtechnology” (Prof. Dr.-Ing. Alfred Ludwig, Institute for Materials) and “Materials Science and Engineering” (Prof. Dr.-Ing. Gunther Eggeler, Institute for Materials) and in cooperation with the Materials Research Department at the RUB.

Title record

Zarnetta, R., Takahashi, R., Young, M. L., Savan, A., Furuya, Y., Thienhaus, S., Maass, B., Rahim, M., Frenzel, J., Brunken, H., Chu, Y. S., Srivastava, V., James, R. D., Takeuchi, I., Eggeler, G. & Ludwig, A.: Identification of quaternary shape memory alloys with near zero thermal hysteresis and unprecedented functional stability, In: Advanced Functional Materials 2010, 20, 1917-1923), doi: 10.1002/adfm.200902336

Further information

Prof. Dr.-Ing. Alfred Ludwig, Materials for Microtechnology, Institute for Materials, Faculty of Mechanical Engineering, Ruhr-Universität Bochum, Tel. 0234/32-27492, alfred.ludwig@rub.de

http://www.rub.de/wdm and http://www.rub.de/sfb459

Robert Zarnetta, Materials Research Department, Ruhr-Universität Bochum, Tel. 0234/32-25929, robert.zarnetta@rub.de

Dr. Josef König | idw
Further information:
http://www.rd.rub.de/is3
http://www.rub.de/sfb459

More articles from Materials Sciences:

nachricht Move over, Superman! NIST method sees through concrete to detect early-stage corrosion
27.04.2017 | National Institute of Standards and Technology (NIST)

nachricht Control of molecular motion by metal-plated 3-D printed plastic pieces
27.04.2017 | Ecole Polytechnique Fédérale de Lausanne

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Fighting drug resistant tuberculosis – InfectoGnostics meets MYCO-NET² partners in Peru

28.04.2017 | Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

 
Latest News

Wireless power can drive tiny electronic devices in the GI tract

28.04.2017 | Medical Engineering

Ice cave in Transylvania yields window into region's past

28.04.2017 | Earth Sciences

Nose2Brain – Better Therapy for Multiple Sclerosis

28.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>