Researchers Study Self-Healing Metal Fusion

WEDNESDAY, AUGUST 2, 2023


A research team from Sandia National Laboratories and Texas A&M University have reportedly observed pieces of metal crack and then fuse back together without any human intervention. The new finding, published in the journal Nature, reportedly overturns current scientific theories in this process.

According to the release, if the newly discovered phenomenon can be harnessed, it could possibly revolutionize engineering, allowing for self-healing engines, bridges and airplanes, while also reversing damages caused by wear and tear.

About the Discovery

In 2013, then-assistant professor at the Massachusetts Institute of Technology’s department of materials science and engineering Michael Demkowicz began “chipping away” at conventional metals theory. According to the report, he eventually published a new theory, based on computer simulations, that under certain conditions metal would be able to weld shut cracks formed by wear and tear. 

The discovery then “inadvertently” happened at the Center for Integrated Nanotechnologies, a Department of Energy user facility operated by Sandia and Los Alamos national laboratories.

According to the release, the discovery was made by experiment leaders Khalid Hattar, now an associate professor at the University of Tennessee, Knoxville, and Chris Barr of the Department of Energy’s Office of Nuclear Energy. The two were reportedly running the experiment at Sandia and had only meant to evaluate how cracks formed and spread through a nanoscale piece of platinum.

The release states that the initial research had included the use of a “specialized” electron microscope technique that they had developed to repeatedly pull on the ends of the metal 200 times per second. About 40 minutes into the experiment, the damage reportedly reversed its course, one end of the crack fused back together “as if it was retracing its steps, leaving no trace of the former injury.”

According to the release, over time, the crack regrew along a different direction.

“This was absolutely stunning to watch first-hand,” said Sandia Materials Scientist Brad Boyce. “What we have confirmed is that metals have their own intrinsic, natural ability to heal themselves, at least in the case of fatigue damage at the nanoscale”.

Boyce, who was aware of the theory, then reportedly shared his findings with Demkowicz. In response, Demkowitcz recreated the experiment on a computer model, substantiating that the phenomenon at Sandia was the same one he had theorized years prior.

“Cracks in metals were only ever expected to get bigger, not smaller. Even some of the basic equations we use to describe crack growth preclude the possibility of such healing processes,” Boyce said.

The release states that fatigue damage is one way that machines wear out and eventually break. Repeated stress or motion reportedly causes microscopic cracks to form, which, over time, grow and spread until the whole device fails.

The fissure that Boyce and his team saw disappear was reportedly one of these tiny but consequential fractures, measured in nanometers.

“From solder joints in our electronic devices to our vehicle’s engines to the bridges that we drive over, these structures often fail unpredictably due to cyclic loading that leads to crack initiation and eventual fracture,” Boyce said.

“When they do fail, we have to contend with replacement costs, lost time and, in some cases, even injuries or loss of life. The economic impact of these failures is measured in hundreds of billions of dollars every year for the U.S.”

The work was supported by the Department of Energy’s Office of Science, Basic Energy Sciences, the National Nuclear Security Administration and the National Science Foundation.

A lot remains unknown about the self-healing process, including whether it will become a practical tool in a manufacturing setting. However, the release states that the discovery remains a leap forward at the frontier of materials science.

“The extent to which these findings are generalizable will likely become a subject of extensive research,” Boyce said. “We show this happening in nanocrystalline metals in vacuum. But we don’t know if this can also be induced in conventional metals in air.”

“My hope is that this finding will encourage materials researchers to consider that, under the right circumstances, materials can do things we never expected,” Demkowicz said.

Similar News

Also this month, researchers at the Indian Institute of Technology (IIT) Bhilai have reportedly developed a new formulation for a “self-healing” polymeric coating for solar cells, demonstrating the ability to heal cracks within five minutes. 

According to the report published in the European Polymer Journal, the team, led by Dr. Sanjib Banerjee from the department of chemistry, plans to evaluate the formulation for potential aerospace applications. 

According to one report from clean energy communications and consulting group Mercom India, the self-healing coat material is a polymer called PSt-b-PTEVE, synthesized through a water tolerant method called cationic polymerization. This polymer, according to researchers, can heal cracks independently due to its redox responsiveness.

The researchers stated that a primary motivation for the project was solar cells’ “critical” role in combating climate change through harnessing sunlight to generate power, without fuel consumption or producing harmful emissions.

According to another report from Times of India, prolonged exposure to hot and humid environmental conditions can inflict damage on solar cells, hampering their efficiency and performance. The introduction of the new self-healing coating material is now reportedly expected to change this, as it can prevent crack propagation and system failures.

Additionally, the simplicity, cost-effectiveness and "industry-friendly nature" of the process reportedly bode well for its eventual integration into solar cell manufacturing. Researchers stated that the venture holds the promise of enhancing the reliability and performance of aerospace technology, making it more resilient to environmental stressors.

Researchers also stated that though nature offers some examples of self-healing phenomena, translating them to engineering materials for practical purposes could present significant challenges.

The project was reportedly supported by IIT Bhilai, the Department of Scientific and Industrial Research (DSIR) and the Space Experiments Review Board (SERB). The team of researchers, including Subrata Dolui, Bhanendra Sahu, Devendra Kumar and Dr. Sanjib Banerjee, now reportedly aim to bridge this gap and bring self-healing technology to practical applications.

   

Tagged categories: Asia Pacific; Colleges and Universities; EMEA (Europe, Middle East and Africa); Latin America; Metals; North America; Program/Project Management; Repair materials; Research; Research and development; Self-healing; Technology; Tools & Equipment; Z-Continents

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