Metallic Glass 101
A new "instruction manual" for metallic glasses could expand their use and application base.
Researchers at The University of New South Wales (UNSW) have created an “instruction manual” for developing metallic glass, an ultra-tough yet flexible alloy described as the most significant materials science innovation since plastic. Just like something from science fiction (think of the liquid-metal robot assassin in the “Terminator” films), these materials behave more like glass or plastic than metal. While still being metals, they become as malleable as chewing gum when heated and can be easily molded or blown like glass. They are also three times stronger and harder than ordinary metals, on average, and are among the toughest materials known.
Most metals are crystalline when solid, with their atoms arranged in a highly organized and regular manner. Metallic glass alloys, however, have a highly disordered structure, with the atoms arranged in a non-regular way. “There are many types of metallic glass, with the most popular ones based on zirconium, palladium, magnesium, titanium or copper,” says Kevin Laws, Ph.D., of UNSW and author of the recent study published in the journal Nature Communications. “But until now, discovering alloy compositions that form these materials has required a lengthy process of trial and error in the laboratory.”
In the study, Laws and his colleagues describe the first model of the atomic structure of metallic glass, which allows scientists to predict the metal combinations that will have glass-forming ability. In the past few years, they have used their model to successfully predict more than 200 new metallic glass alloys based on magnesium, silver, copper, zinc and titanium. It is expected that this ability to predict which combinations of metals will best form metallic glasses will make the process easier and less expensive.
“With our new instruction manual, we can start to create many new useful metallic glass-types and begin to understand the atomic fundamentals behind their exceptional properties,” Lays says. “We will also be able to engineer these materials on an atomic scale so they have the specific properties we want. Metallic glass alloys are expensive to manufacture and, to date, have only been used in niche products such as ejector pins for iPhones, watch springs for expensive hand-wound watches, trial medical implants, and tennis racquets and golf clubs. They are also planned for use in the next Mars rover vehicle. But if they become easier and cheaper to make, they could be widely used in many applications, including as exceptionally strong components in personal electronic devices, in space exploration vehicles, and as hydrogen storage materials in next-generation batteries.”
The research team includes Laws and Professor Michael Ferry of the UNSW School of Materials Science and Engineering, and Daniel Miracle, Ph.D., of the Air Force Research Laboratory, U.S. Materials and Manufacturing Directorate.
For additional information, visit www.unsw.edu.au.