Scientists from Peter the Great St.Petersburg Polytechnic University (SPbPU) in collaboration with the Institute of Metallurgy and Material Science of the Russian Academy of Sciences and Leibniz University Hannover developed multifunctional metal alloys that absorb and emit heat at the same time and change their volume and size under the influence of a magnetic field. This effect is caused by changes in the structure of the substance. The alloys may be used in medicine and industry. The results of the groundbreaking study were published in the Key Engineering Materials journal.
When magnetized, certain bodies change their linear dimensions and volume. The magnetic properties of rare metals are of great interest today.
A team of scientists from St. Petersburg Polytechnic University calculated the combination of components in an alloy that would allow for heat absorption, emission, size and shape changes within a wide range of temperatures including those close to human body temperature. In such alloys, dysprosium, gadolinium, terbium, and cobalt should be combined, and aluminum should be added. The alloys were manufactured at the Institute of Electrical Engineering at Leibniz University Hannover.
The obtained material can be used to develop magnetostrictive transducers. They serve as filters, sensors, and resonators that transform the magnetic field into mechanical oscillations and vice versa. This is a significant function for various devices, such as material integrity controllers that help in finding air bubbles within constructions. If such air bubbles are not identified and removed, they may cause a lot of damage. Also, a transducer can serve as a basis for developing sensitive vibration gauges used to register earthquake shocks, as well as a receiver and a source of sound waves for underwater works.
Researchers from the Institute of Metallurgy and Material Science of the Russian Academy of Sciences studied the effects of magnetic field on the alloy. The surface of the substance was probed with a thin needle able to detect every indent or mount. The scientists demonstrated that the surface of the alloy is covered in stripes and that their layout changes under the influence of the magnetic field. Thus, they were able to see the restructuring of the metal that explains the magnetostriction effect.
Alexey Filimonov, the head of the Department of Physical Electronics at Peter the Great St. Petersburg Polytechnic University says: “Transducers based on our alloys are going to be much more long-lasting than the existing analogs and will work in a wide range of magnetic fields. Besides, the alloys may be used in medicine so they can change their shape under the influence of magnetic fields that are safer for human health. E.g., one can develop arterial stents that could flow in the bloodstream in a compact form and then unfold at a given place. This is possible because the operating temperature range of our materials is close to human body temperature.”