Yale researchers have uncovered a new technology that may revolutionize the use of metallic glass. By creating metallic glass at the nanoscale (“NMG”) using three-dimensional fabricating technology, these researchers illustrate how manufacturers can reap the benefits of metallic glass, like the complete customization of its chemical properties, without the pitfalls they encountered in past applications, including molding degradation and unstable manufacturing processes.
Metallic glass is a type of alloy that allows a metal to act like a glass by simply altering its atomic structure. Also known as amorphous metal because of its scattered atomic structure, metallic glass experiences glass transition when heated which allows for greater flexibility in shape. Because the atomic structure of metallic glass is amorphous, instead of crystalline (uniform), it provides for a material that is much stronger and less stiff than its common metal counterpart. This flexibility and strength creates stored energy. Applications include golf clubs, tennis rackets, and phone cases. Watch this video demonstration to see why.
Even though metallic glass was first discovered in 1960, its commercial viability has been hampered by the die-cast fabrication process and cost of high-purity materials. For example, golf clubs made with die-casted metallic glass created flow lines on the clubs which made them shatter after repeated use. In addition to inconsistent production issues, the high temperatures required during the fabrication process of metallic glass degraded molds, reducing the number of times they could be used, and increasing costs in the manufacturing process.
Metallic glass is a type of alloy that allows a metal to act like a glass by simply altering its atomic structure.
Metallic glass is homogenous and isotropic down to the atomic scale. This is particularly useful when fabricating materials at the nanoscale because those building blocks must be even smaller than the nano-structure. At the nano-scale, the first application of metallic glass was in nanorods. This development highlighted the need for effective and efficient molding techniques. The Yale researchers accepted that challenge creating a “bottom-up” method to fabricate NMGs in three-dimensional shapes using vapor guns sputtering from multiple targets. Producing NMGs using this three-dimensional method allows for greater surface area without the need for additional processing steps required when using conventional molding techniques, which can compromise the structure. The three-dimensional fabrication technique manipulates the shape of an NMG on three axes allowing for unique formability and providing exceptional shape capabilities not achievable with other processes — the implications of which are endless.
Additionally, an infinite variety of chemical compositions can be realized using this process, allowing manufacturers to tailor materials to exhibit desired electrochemical behaviors in computers or batteries, for example. NMGs may also be used to alter a materials biocompatibility or susceptibility to corrosion which could allow for a number of medical device applications.
The three-dimensional technique even allows for a completely new type of NMG, a hybrid-NMG which combines metallic glass with other compounds at the atomic level, simply by adjusting the composition and speed of the three-dimensional guns. Despite the chemical differences between the nanoparticles in the hybrid-NMGs, this process maintains uniform shape and structure. Hybrid-NMGs that integrate multiple composites will create diverse and completely customizable functionalities.
Innovative fabrication techniques, like the ones discovered by these Yale researchers, may be the catalyst for a reintroduction of metallic glass, now at the nanoscale, into the manufacturing marketplace. Material scientists hope that metallic glass will eventually displace traditional specialty metals and machining which opens the door for countless innovative manufacturing possibilities.