Steel is one of the most commonly used materials, possibly because it has many different variants, Typical variations are stainless steel, high-strength quenched and tempered steel, or low-price structural steel. Additionally, steel has a variety of important applications, from cutlery and automotive components to the steel girders of buildings and bridges, to name just a few. Considering the latter, you can imagine steel is constantly being exposed to extreme heat and stress. According to experts, this causes material fatigue that ultimately leads to damage. How can this damage be detected? While magnets play a key role in detecting early damage in magnetic steel, researchers are now exploring detection options for non-magnetic materials.

Advancement in Techniques

Researchers have been working on coating non-magnetic steel with different magnetic materials. Each film is 20 nanometers thin and comprised of terfenol-D, an alloy of the chemical elements terbium, iron, and dysprosium, or of permalloy, a nickel-iron compound. After the material is coated, the scientists looked for strains in the material on a microscopic level. "We observed a characteristic change in the magnetic domain structure," explained Dr. Martin Jourdan from the Institute of Physics at JGU. "Microscopic strain in non-magnetic steel causes the direction of magnetization of the thin layer to change." Compared to traditional testing procedures, this new method is proving to be successful. It is showing material fatigue at much earlier stages. Additionally, it is effective at the micrometer level. Ultimately, this method could be used for testing materials other than non-magnetic steel as well as other metals, such as aluminum and titanium, and certain composite materials. The efforts of this research are credited to the work undertaken by the Transregional Collaborative Research Center (CRC/TRR) "Spin+X: Spin in its collective environment," which is based at TU Kaiserslautern and Johannes Gutenberg University Mainz and financed by the German Research Foundation (DFG). Seeking more magnetic news? Take a look at our blog page for more articles like this one and more magnet topics! You can even learn how to find out if there is magnetic material (such as nails) in your non-magnetic floors or walls.