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 Superconductivity research reveals potential new state of matter
17.08.2017 | DOE/Los Alamos National Laboratory

nachricht Spray-on electric rainbows: Making safer electrochromic inks
17.08.2017 | Georgia Institute of Technology

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

Gold shines through properties of nano biosensors

17.08.2017 | Physics and Astronomy

Greenland ice flow likely to speed up: New data assert glaciers move over sediment, which gets more slippery as it gets wetter

17.08.2017 | Earth Sciences

Mars 2020 mission to use smart methods to seek signs of past life

17.08.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>