Bulk metallic glasses material is strong as steel and moldable as plastic

For decades, materials scientists have been trying to come up with a substance which could be molded into complex shapes with the same ease and low expense as plastic but without sacrificing the strength and durability of metal. A team of researchers from Yale University came up with such material that would cost about the same as high-end steel, but it could be processed as cheaply as plastic.

Led by Jan Schroers, a materials scientist at Yale University, the team of researchers has shown that recently developed Bulk Metallic Glasses (BMGs)-metal alloys with randomly arranged atoms can be blow molded like plastics into complex shapes that can’t be achieved using regular metal, yet without sacrificing the strength or durability that metal affords.

The team blow molded the alloys at low temperatures and low pressures, where the bulk metallic glass dramatically softens and flows as easily as plastic but without crystallizing like regular metal. The low temperatures and low pressures allowed the team to shape the BMGs with ease, versatility and precision. In order to carefully control and maintain the ideal temperature for blow molding, the team shaped the BMGs in a vacuum or in fluid.

“The trick is to avoid friction typically present in other forming techniques”, said Schroers. “Blow molding completely eliminates friction, allowing us to create any number of complicated shapes, down to the nanoscale.”

In addition, by blow molding the BMGs, the team was able to combine three separate steps in traditional metal processing (shaping, joining and finishing) into one, thus reducing both time and energy needed for metal processing. The alloys are made up of different metals, including zirconium, nickel, titanium and copper.

Schroers and his team are already using their new processing technique to fabricate miniature resonators for microelectromechanical systems (MEMS)-tiny mechanical devices powered by electricity-as well as gyroscopes and other resonator applications. They have also created a number of complex shapes-including seamless metallic bottles, watch cases, miniature resonators and biomedical implants-that can be molded in less than a minute and are twice as strong as typical steel.

“This could enable a whole new paradigm for shaping metals”, said Schroers. “The superior properties of BMGs relative to plastics and typical metals, combined with the ease, economy and precision of blow molding, have the potential to impact society just as much as the development of synthetic plastics and their associated processing methods have in the last century.”

For more information, read the paper published in journal Materials Today named: “Thermoplastic blow molding of metals“.