Researchers from Northwestern University and Boise State University have figured out how to produce a less expensive shape-shifting "memory" foam, which could lead to more widespread applications of the material, such as in surgical positioning tools and valve mechanisms.
David Dunand, the James N. and Margie M. Krebs Professor of Materials Science and Engineering at Northwestern, has been collaborating with Peter Müllner, professor of materials science and engineering at Boise State, on a project focused on a nickel-manganese-gallium alloy that changes shape when exposed to a magnetic field.
The alloy retains its new shape when the field is turned off but returns to its original shape if the field is rotated 90 degrees, demonstrating "magnetic shape-memory." The alloy can be activated millions of times, and it deforms reliably and reproducibly as a result. This property could be used to advantage in fast-operating actuators (mechanical devices for moving or controlling a mechanism or system) in inkjet printers, car engines and surgical tools.
To date, the magnetic shape-memory effect has occurred only in nickel-manganese-gallium single crystals, which are much more difficult and expensive to create than the more common polycrystals.
Now, Dunand, Müllner and their colleagues have created easily processable polycrystalline foams with shape-changing properties resembling those of the much more expensive single crystals. They did this by introducing small pores into the "nodes" of their original metallic foam, which, much like a sponge, consisted of struts connected by relatively large nodes. Adding a second level of porosity allowed for deformation and retention in the polycrystalline foam of some of the shape-memory properties.
The results are published online by the journal Nature Materials.
"One key aspect of this new 'smart' foam is that, together with a simple coil to produce a magnetic field, it creates a linear actuator of extreme simplicity -- and thus high reliability and miniaturization potential -- replacing a much more complex electro-mechanical system with many moving parts," Dunand said.
Potential applications range from replacing materials currently being used in sonar devices, precision actuators and magneto-mechanical sensors to enabling new devices in biomedicine and microrobotics.
"This was such a huge improvement that the foam was tested over and over again to make sure that no experimental mistakes were made," Müllner said. "Our new results may pave the way for magnetic shape-memory alloys for use in research labs and commercial applications."
Northwestern and Boise State have jointly filed a patent application.
The title of the Nature Materials paper is "Giant Magnetic-field-induced Strains in Polycrystalline Ni–Mn–Ga Foams." In addition to Dunand and Müllner, other authors of the paper are Xuexi Zhang, a visiting professor in Dunand's lab from China's Harbin Institute of Technology, and Markus Chmielus and Cassie Witherspoon, graduate students at Boise State.
Megan Fellman | EurekAlert!
ADIR Project: Lasers Recover Valuable Materials
21.07.2017 | Fraunhofer-Institut für Lasertechnik ILT
High-tech sensing illuminates concrete stress testing
20.07.2017 | University of Leeds
Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.
For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...
What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.
To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...
The research team of Prof. Dr. Oliver Einsle at the University of Freiburg's Institute of Biochemistry has long been exploring the functioning of nitrogenase....
A one trillion tonne iceberg - one of the biggest ever recorded -- has calved away from the Larsen C Ice Shelf in Antarctica, after a rift in the ice,...
Physics supports biology: Researchers from PTB have developed a model system to investigate friction phenomena with atomic precision
Friction: what you want from car brakes, otherwise rather a nuisance. In any case, it is useful to know as precisely as possible how friction phenomena arise –...
21.07.2017 | Event News
19.07.2017 | Event News
12.07.2017 | Event News
21.07.2017 | Earth Sciences
21.07.2017 | Power and Electrical Engineering
21.07.2017 | Physics and Astronomy