Mouldable metals
13 Apr 2011 by Evoluted New Media
Stronger than steel but as versatile as plastic – scientists have developed a substance that can be moulded into complex shapes as easily as plastics, but without losing the strength of steel.
Stronger than steel but as versatile as plastic – scientists have developed a substance that can be moulded into complex shapes as easily as plastics, but without losing the strength of steel.
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Jan Schroers and his team have developed novel metal alloys that can be blow moulded into virtually any shape Credit: Michael Marsland/Yale University |
A team of material scientists at Yale – led by Jan Schroers – has created bulk metallic glasses (BMGs). These BMGs are metal alloys made up of different metals – including zirconium, nickel, titanium and copper – that have randomly arranged atoms as opposed to the orderly crystalline structure found in ordinary metals.
“These alloys look like ordinary metal but can be blow moulded just as cheaply and as easily as plastic,” Schroers said.
The BMGs can be blow moulded like plastics into complex shapes that can’t be achieved using regular metals, but without sacrificing the strength or durability of the metals. The process takes place at low temperatures and low pressures, where the BMG softens dramatically and flows as easily as a plastic but without crystallising like a regular metal.
Schroers said the low temperature and low pressures allow the team to shape the BMGs with ease, versatility and precision. In order to carefully control and maintain the ideal temperature, the BMGs are shaped in a vacuum or fluid.
“The trick is to avoid friction typically present in other forming techniques,” Schroers said. “Blow moulding completely eliminated friction, allowing us to create any number of complicated shapes, down to the nanoscale.”
The process combines three separate steps in the traditional metal processing – shaping, joining and finishing – into one. The team has created a number of complex shapes, including seamless metallic bottles, watch cases, and biomedical implants. They can be moulded in less than a minute and are twice as strong as steel.
Miniature resonators have also been created using the new technique. These can be used in microelectromechanical systems (MEMS) – tiny mechanical devices powered by electricity – as well as in gyroscopes and other resonator applications.
