Nav: Home

An alloy that retains its memory at high temperatures

December 03, 2019

Using computer simulation, Alberto Ferrari calculated a design proposal for a shape memory alloy that retains its efficiency for a long time even at high temperatures. Alexander Paulsen manufactured it and experimentally confirmed the prediction. The alloy of titanium, tantalum and scandium is more than just a new high-temperature shape memory alloy. Rather, the research team from the Interdisciplinary Centre for Advanced Materials Simulation (Icams) and the Institute for Materials at Ruhr-Universität Bochum (RUB) has also demonstrated how theoretical predictions can be used to produce new materials more quickly. The group published its report in the journal Physical Review Materials from 21 October 2019. Their work was showcased as Editor's suggestion.

Avoiding the unwanted phase

Shape memory alloys can re-establish their original shape after deformation when the temperature changes. This phenomenon is based on a transformation of the crystal lattice in which the atoms of the metals are arranged. Researchers refer to is as phase transformation. "In addition to the desired phases, there are also others that form permanently and considerably weaken or even completely destroy the shape memory effect," explains Dr. Jan Frenzel from the Institute for Materials. The so-called omega phase occurs at a specific temperature, depending on the composition of the material. To date, many shape memory alloys for the high temperature range would withstand only a few deformations before they became unusable once the omega phase set in.

Promising shape memory alloys for high temperature applications are based on a mixture of titanium and tantalum. By changing the proportions of these metals in the alloy, researchers can determine the temperature at which the omega phase occurs. "However, while we can move this temperature upward, the temperature of the desired phase transformation is unfortunately lowered in the process," says Jan Frenzel.

Admixture alters properties

The RUB researchers attempted to understand the mechanisms of the onset of the omega phase in detail, in order to find ways to improve the performance of shape memory alloys for the high-temperature range. To this end, Alberto Ferrari, PhD researcher at Icams, calculated the stability of the respective phases as a function of temperature for different compositions of titanium and tantalum. "He was able to use it to confirm the results of experiments," points out Dr. Jutta Rogal from Icams.

In the next step, Alberto Ferrari simulated small amounts of third elements being added to the shape memory alloy of titanium and tantalum. He selected the candidates according to specific criteria, for example they should be as non-toxic as possible. It emerged that an admixture of a few percent of scandium would have to result in the alloy functioning for a long time even at high temperatures. "Even though scandium belongs to the rare earths and is, consequently, expensive, we only need very little of it, which is why it's worth using anyway", explains Jan Frenzel.

Prediction is accurate

Alexander Paulsen then produced the alloy calculated by Alberto Ferrari at the Institute for Materials and tested its properties in an experiment: the results confirmed the calculations. A microscopic examination of the samples later proved that even after many deformations no omega phase was found in the crystal lattice of the alloy. "We have thus expanded our basic knowledge of titanium-based shape memory alloys and developed possible new high-temperature shape memory alloys," says Jan Frenzel. "Moreover, it's great that the computer simulation predictions are so accurate." Since the production of such alloys is very complex, the implementation of computer-aided design proposals for new materials promises much faster success.
-end-
Funding

The research was funded by the German Research Foundation as part of research group 1766 (project no. 200999873). Some of the calculations were performed using supercomputers by the Swedish National Infrastructure for Computing at National Supercomputer Centre (NSC) in Linköping and at the Center for High Performance Computing in Stockholm.

Original publication

Alberto Ferrari, Alexander Paulsen, Dennis Langenkämper, David Piorunek, Christoph Somsen, Jan Frenzel, Jutta Rogal, Gunther Eggeler, Ralf Drautz: Discovery of ω-free high-temperature Ti-Ta-X shape memory alloys from first-principles calculations, in: Physical Review Materials 2019, DOI: 10.1103/PhysRevMaterials.3.103605

Press contact

Dr. Jutta Rogal
Atomistic simulation of the kinetics of phase transformations
Interdisciplinary Centre for Advanced Materials Simulation
Ruhr-Universität Bochum
Phone: +49 234 32 29317
Email: jutta.rogal@rub.de

Dr. Jan Frenzel
Chair for Materials Science and Engineering
Institute for Materials
Department of Mechanical Engineering
Ruhr-Universität Bochum
Phone: +49 234 32 22547
Email: jan.frenzel@rub.de

Ruhr-University Bochum

Related Titanium Articles:

Skoltech scientists developed a new cathode material for metal-ion batteries
Researchers from the Skoltech Center for Energy Science and Technology (CEST) created a new cathode material based on titanium fluoride phosphate, which enabled achieving superior energy performance and stable operation at high discharge currents.
First view of hydrogen at the metal-to-metal hydride interface
University of Groningen physicists have visualized hydrogen at the titanium/titanium hydride interface using a transmission electron microscope.
The properties of thin titanium oxide films have been studied
Some titanium oxides are known for their unique properties, such as increased photocatalytic activity (i.e. they effectively use light to speed up chemical reactions).
Adding copper strengthens 3D-printed titanium
Successful trials of titanium-copper alloys for 3D printing could kickstart a new range of high-performance alloys for medical device, defence and aerospace applications.
Fatigue-resistant, high-performance cooling materials enabled by 3D printing
High-performance solid-state elastocaloric cooling materials with exceptional fatigue resistance are made possible by 3D printing a nickel-titanium based alloy, researchers report.
Common food additive found to affect gut microbiota
Experts call for better regulation of a common additive in foods and medicine, as research reveals it can impact the gut microbiota and contribute to inflammation in the colon, which could trigger diseases such as inflammatory bowel diseases and colorectal cancer.
Layering titanium oxide's different mineral forms for better solar cells
A Japan-based research team led by Kanazawa University improved the efficiency of a new type of solar cell with a double layer consisting of pure anatase and brookite, two different mineral forms of titanium oxide.
Penn engineer's 'metallic wood' has the strength of titanium and the density of water
In a new study published in Nature Scientific Reports, researchers at the University of Pennsylvania's School of Engineering and Applied Science, the University of Illinois at Urbana-Champaign, and the University of Cambridge have built a sheet of nickel with nanoscale pores that make it as strong as titanium but four to five times lighter.
Alcohols as carbon radical precursors
Carbon radicals are attractive intermediates for organic synthesis because of their diversity and high reactivities.
Aluminum on the way to titanium strength
NUST MISIS scientists have proposed a technology that can double the strength of composites obtained by 3D printing from aluminum powder, and advance the characteristics of these products to the quality of titanium alloys: titanium's strength is about six times higher than that of aluminum, but the density of titanium is 1.7 times higher.
More Titanium News and Titanium Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Teaching For Better Humans 2.0
More than test scores or good grades–what do kids need for the future? This hour, TED speakers explore how to help children grow into better humans, both during and after this time of crisis. Guests include educators Richard Culatta and Liz Kleinrock, psychologist Thomas Curran, and writer Jacqueline Woodson.
Now Playing: Science for the People

#556 The Power of Friendship
It's 2020 and times are tough. Maybe some of us are learning about social distancing the hard way. Maybe we just are all a little anxious. No matter what, we could probably use a friend. But what is a friend, exactly? And why do we need them so much? This week host Bethany Brookshire speaks with Lydia Denworth, author of the new book "Friendship: The Evolution, Biology, and Extraordinary Power of Life's Fundamental Bond". This episode is hosted by Bethany Brookshire, science writer from Science News.
Now Playing: Radiolab

Space
One of the most consistent questions we get at the show is from parents who want to know which episodes are kid-friendly and which aren't. So today, we're releasing a separate feed, Radiolab for Kids. To kick it off, we're rerunning an all-time favorite episode: Space. In the 60's, space exploration was an American obsession. This hour, we chart the path from romance to increasing cynicism. We begin with Ann Druyan, widow of Carl Sagan, with a story about the Voyager expedition, true love, and a golden record that travels through space. And astrophysicist Neil de Grasse Tyson explains the Coepernican Principle, and just how insignificant we are. Support Radiolab today at Radiolab.org/donate.