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 Plant inspiration could lead to flexible electronics
22.06.2017 | American Chemical Society

nachricht A rhodium-based catalyst for making organosilicon using less precious metal
22.06.2017 | Tokyo 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: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

Im Focus: Optoelectronic Inline Measurement – Accurate to the Nanometer

Germany counts high-precision manufacturing processes among its advantages as a location. It’s not just the aerospace and automotive industries that require almost waste-free, high-precision manufacturing to provide an efficient way of testing the shape and orientation tolerances of products. Since current inline measurement technology not yet provides the required accuracy, the Fraunhofer Institute for Laser Technology ILT is collaborating with four renowned industry partners in the INSPIRE project to develop inline sensors with a new accuracy class. Funded by the German Federal Ministry of Education and Research (BMBF), the project is scheduled to run until the end of 2019.

New Manufacturing Technologies for New Products

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

A new technique isolates neuronal activity during memory consolidation

22.06.2017 | Life Sciences

Plant inspiration could lead to flexible electronics

22.06.2017 | Materials Sciences

A rhodium-based catalyst for making organosilicon using less precious metal

22.06.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>