Research has shown that damaged metal can heal itself to its original state when certain conditions are met. Self-healing of metals, such as bridges that are durable even after decades, buildings that automatically recover after an earthquake, and machines that repair themselves, are expected to bring about an engineering revolution.
A joint research team led by Brad Boyce , senior researcher at Sandia National Laboratory, USA, and Michael Demkowicz, professor of materials science and engineering at Texas A&M University, published a study in the international journal Nature on the 19th that found that the metal repaired the damaged area by itself as a result of applying pressure to the metal in a vacuum . The research team studied ‘fatigue cracks’ caused by wear over time rather than self-healing of the metal. It is to see how microscopic cracks grow and spread in the process of using metal objects. As 90%먹튀검증 of machines made of metal fail due to gradual fatigue cracking, the goal is to identify the cause of failure due to vibration and stress. “These structures, from vehicle engines to bridges, are subject to cyclical loads leading to micro-cracks, leading to unpredictable failures,” said Boyce.
However, the direction of the study changed during the course of the experiment. The research team cracked platinum and copper in a vacuum in the unit of nm (nanometer 1 nm is 1 billionth of a meter), and then grabbed both ends and pulled them repeatedly 200 times per second. Later, as a result of checking with a special microscope, the metal showed a movement to fill the cracked area. There are self-healing materials made of plastic, but this is the first time that metal self-healing has been confirmed.
The theory that metals can be restored without heating or chemical treatment has been suggested before. Professor Demkowitz argued in 2013 that metal cracks can be healed by ‘cold welding’, which restores the performance of the defective part only with pressure without applying heat. It is explained that a monotonous tensile load causes ‘ Disclination ‘, which is a disturbance of the atomic arrangement, to mitigate the damage.
This study proved the theory proposed by Professor Demkowitz in 2013 as a fact after 10 years. Professor Demkowitz reproduced the phenomena observed by the research team with a microscope through computer modeling and confirmed the same as his theory. The cracks in the metal cracked in nanometers were fused together after repeated vibrations, leaving no traces of scars.
The research team’s discovery of metal self-healing is expected to open a new horizon in the field of materials science. It is still unclear whether the same phenomenon will occur in air, but the research team explains that innovative developments related to metal devices are possible if this principle is applied to a manufacturing environment.
“This phenomenon occurs in nanocrystalline metals in a vacuum,” said lead researcher Boyce. “Generalizing this finding will be a subject of extensive research in the future.” “We don’t know if it can be induced from metals in the air, but it’s hopeful that materials science researchers will consider that materials can do unexpected things under the right circumstances,” he said.