Scientists have developed a new alloy composed of multiple metals that exhibits nearly zero thermal expansion across an exceptionally wide temperature range.
Most metals expand as their temperature rises. The Eiffel Tower, for example, stands about 10 to 15 centimeters taller in summer than in winter due to thermal expansion. However, this effect is highly undesirable for many technical applications. As a result, researchers have long sought materials that maintain a constant length regardless of temperature. One such material is Invar, an iron-nickel alloy known for its extremely low thermal expansion. The physical explanation for this property, however, remained unclear until recently.
Now, a collaboration between theoretical researchers at the Vienna University of Technology (TU Wien) and experimentalists at the University of Science and Technology Beijing has led to a significant breakthrough. Using complex computer simulations, they have unraveled the invar effect in detail and developed a so-called pyrochlore magnet—an alloy with even better thermal expansion properties than Invar. Over an exceptionally wide temperature range of more than 400 Kelvins, its length changes by only about one ten-thousandth of one percent per Kelvin.
Thermal expansion and its antagonist
“The higher the temperature in a material, the more the atoms tend to move – and when the atoms move more, they need more space. The average distance between them increases,” explains Dr Sergii Khmelevskyi from the Vienna Scientific Cluster (VSC) Research Centre at TU Wien. “This effect is the basis of thermal expansion and cannot be prevented. But it is possible to produce materials in which it is almost exactly balanced out by another, compensating effect.”
Segii Khmelevskyi and his team developed complex computer simulations that can be used to analyze the behavior of the magnetic materials at finite temperatures on the atomic level. “This enabled us to better understand the reason why invar hardly expands at all,” says Khmelevskyi. “The effect is due to certain electrons changing their state as the temperature rises. The magnetic order in the material decreases, causing the material to contract. This effect almost exactly cancels the usual thermal expansion.”
It had already been known that the magnetic order in the material is responsible for the invar effect. But only with the computer simulations from Vienna, it became possible to understand the details of this process so precisely that predictions for other materials could be made. “For the first time, a theory is available that can make concrete predictions for the development of new materials with vanishing thermal expansion,” says Sergii Khmelevskyi.
The pyrochlore magnet with Kagome planes
In order to test these predictions in practice, Sergii Khmelevskyi worked together with the experimental team of Prof. Xianran Xing and Ass. Prof. Yili Cao from the Institute of the Solid State Chemistry of the University of Science and Technology Beijing. The result of this cooperation has now been presented: The so-called pyrochlore magnet.
In contrast to previous invar alloys, which only consist of two different metals, the pyrochlore magnet has four components: Zirconium, niobium, iron, and cobalt. “It is a material with an extremely low coefficient of thermal expansion over an unprecedentedly wide temperature range,” says Yili Cao.
This remarkable temperature behavior has to do with the fact that the pyrochlore magnet does not have a perfect lattice structure that always repeats itself in exactly the same way. The composition of the material is not the same at every point, it is heterogeneous. Some areas contain a little more cobalt, some a little less. Both subsystems react differently to temperature changes. This allows the details of the material composition to be balanced point by point in such a way that the overall temperature expansion is almost exactly zero.
The material could be of particular interest in applications with extreme temperature fluctuations or precise measuring techniques, such as in aviation, aerospace, or high-precision electronic components.
Reference: “Local chemical heterogeneity enabled superior zero thermal expansion in nonstoichiometric pyrochlore magnets” by Yanming Sun, Ruohan Yu, Sergii Khmelevskyi, Kenichi Kato, Yili Cao, Shixin Hu, Maxim Avdeev, Chin-Wei Wang, Chengyi Yu, Qiang Li, Kun Lin, Xiaojun Kuang and Xianran Xing, 17 December 2024, National Science Review.
DOI: 10.1093/nsr/nwae462
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8 Comments
Scientists Develop New Alloy That Breaks the Rules of Thermal Expansion.
Ask the scientists:
If a physical rule can be repeatedly broken, is it complete?
Scientific research guided by correct theories can enable researchers to think more.
A topological vortex is a concept in physics that describes the natural gravitational field or the fluid-body coupled system. A topological vortex is formed by the interaction and balance of vortex and anti-vortex field pairs, which can be set into resonance by the body motion and interaction. Topological Vortex Theory (TVT) treats space as an ideal fluid, posits that the topological vortex gravitational field is fundamental to the structure of the universe, and emphasizes the importance of topological phase transitions in understanding mass, inertia, and energy.
According to the Topological Vortex Theory (TVT), spins create everything, spins shape the world. There are substantial distinctions between Topological Vortex Theory (TVT) and traditional physical theories. Grounded in the inviscid, incompressible, and isotropic spaces, TVT introduces the concept of topological phase transitions and employs topological principles to elucidate the formation and evolution of matter in the universe, as well as the impact of interactions between topological vortices and anti-vortices on spacetime dynamics and thermodynamics.
Within TVT, low-dimensional spacetime matter serves as the foundation for high-dimensional spacetime matter, and the hierarchical structure of matter and its interaction mechanisms challenge conventional macroscopic and microscopic interpretations. The conflict between Quantum Physics and Classical Physics can be attributed to their differing focuses: Quantum Physics emphasizes low-dimensional spacetime matter, whereas Classical Physics centers on high-dimensional spacetime matter.
Subatomic particles in the quantum world often defy the familiar rules of the physical world. The fact repeatedly suggests that the familiar rules of the physical world are pseudoscience. In the familiar rules of the physical world, two sets of cobalt-60 can form the mirror image of each other by rotating in opposite directions, and should receive the Nobel Prize for physics.
Please witness the grand performance of some so-called peer review publications (including PRL, PNAS, Nature, Science, etc.). https://scitechdaily.com/microscope-spacecrafts-most-precise-test-of-key-component-of-the-theory-of-general-relativity/#comment-854286. Some so-called academic publications (including PRL, PNAS, Nature, Science, etc.) are addicted to their own small circles and have deviated from science for a long time.
As the background of various material interactions and movements, space exhibits inviscid, absolutely incompressible and isotropic physical characteristics. It may form various forms of spacetime vortices through topological phase transitions. Hence, vortex phenomena are ubiquitous in cosmic space, from vortices of quantum particles and living cells to tornados and black holes. Stars and radioactive elements are one of the most active topological nodes in spacetime. Utilizing them is more valuable and meaningful than simulating them. Small or micro power topology intelligent batteries may be the direction of future energy research and development for human society.
Under the topological vortex architecture, science and pseudoscience are clear at a glance. Topological Vortex Theory (TVT) can play a crucial role in elucidating the foundations of physics, establishing its principles, and combating pseudoscience. Therefore, TVT has been strongly opposed and boycotted by traditional so-called peer review publications (such as PRL, PNAS, Nature, Science, etc.).
These so-called peer review publications (including PRL, PNAS, Nature, Science, etc.) mislead the direction of science and are known for their various absurdities and wonders. They collude together, reference each other, and use so-called Impact Factor (IF) or the Nobel Prize to deceive people around.
Ask the so-called peer review publications (including PRL, PNAS, Nature, Science, etc.):
1. What are your criteria for distinguishing science from pseudoscience?
2. Is your Impact Factor (IF) the standard for distinguishing science from pseudoscience?
3. Is the Nobel Prize the standard for distinguishing science from pseudoscience?
4. What is the most important aspect of academic publications?
5. Is the most important aspect of academic publications being flashy and impractical articles?
Pseudo academic publications (including PRL, PNAS, Nature, Science, etc.) are neither inclusivity nor openness, nor transparency and fairness, and have already had a serious negative impact on the progress of science and technology. Some so-called peer review publications (including PRL, PNAS, Nature, Science, etc.) are addicted to their own small circle and no longer know what science is. They hardly know what is dirty and ugly.
Publications that mislead the public under the guise of scholarship are more reprehensible than ordinary publications. The field of physics faces an ongoing challenge in maintaining scientific rigor and integrity in the face of pervasive pseudoscientific claims. Fighting against rampant pseudoscience, physics still has a long way to go.
While my comments may be lengthy, they are necessary to combat the proliferation of rampant pseudoscience and to promote the advancement of science and technology, and also is all I can do.
Appreciate the SciTechDaily for its inclusivity, openness, transparency, and fairness. If the researchers are truly interested in cosmic matter, please read: A Brief History of the Evolution of Cosmic Matter (https://scitechdaily.com/microscope-spacecrafts-most-precise-test-of-key-component-of-the-theory-of-general-relativity/#comment-873523).
Don’t sweat it, it was just a clickbaity title. They do that all the time.
How do you decipher the difference between science and pseudoscience, from whose standard as a starting point is used for comparisons?
Topological Vortex Theory (TVT) is based on topology and fluid dynamics, which have solid mathematical and physical foundations. Under the topological vortex architecture, science and pseudoscience are clear at a glance. Topological Vortex Theory (TVT) can play a crucial role in elucidating the foundations of physics, establishing its principles, and combating pseudoscience.
Perfect material for a clock pendulum.
NOT
Have not read the article, nor the comments.
What the mateial is doing is NOT against the Law’s of Physics.
It might be against the Understanding of those who do not know the LAWS of Physics.
Went back and read the article, and comments.
My Position remains NOT
I worked at Coherent, Inc in the 80’s. I worked in R&D. A mechanical engineer named Wayne Mefferd invented the patented “Mefferd Thermal Compensator” which used 3 invar rods as described below. I did some mechanical and electrical design on the Innova lasers.
——
https://www.artisantg.com/info/Coherent_Innova_90_Manual_20207415744.pdf
——
RESONATOR
The INNOVA Series ion lasers all have resonators made of
the low expansion metal, Invar. Three Invar rods mounted
in an L-shaped configuration run the length of the laser.
The excellent rigidity of Invar keeps the laser in good
alignment, even under conditions of exceptional
vibration. While Invar has a higher thermal expansion
coefficient than silica (used in other resonator designs)
this does not affect the stability of the INNOVA Series
ion laser since the rods are thermally compensated. Each
rod has aluminum end -pieces. The aluminum pieces are
re-entrant: thus, as the temperature increases and the
Invar expands outward, the aluminum pieces also expand —
inward. The aluminum outer pieces thermally compensate
each rod. The individual compensation of the rods
eliminates angular misalignment, should one rod reach a
different temperature from the others. Additional thermal
protection is provided by the solenoid. T