Materials scientists as Yale University say some recently developed bulk metallic glasses -- alloys with randomly arranged atoms rather than ordinary metals' rigid, orderly structure -- can be blow molded like plastics into complex shapes that can't be achieved using regular metal but without sacrificing any of the metals' characteristic strength.
"These alloys look like ordinary metal but can be blow molded just as cheaply and as easily as plastic," says Yale scientists Jan Schroers, whose team has created a number of complex shapes including seamless metallic bottles, watch cases, miniature resonators and biomedical implants, molded in less than a minute and twice as strong as typical steel, a Yale release reported.
The alloys -- made up of different metals, including zirconium, nickel, titanium and copper -- cost about the same as high-end steel, Schroers says, but can be processed as cheaply as plastic.
The team blow molded the alloys at low temperatures and low pressures, where the bulk metallic glass softens dramatically and flows as easily as plastic.
In order to carefully control and maintain the ideal temperature for blow molding, the team shaped the alloys in a vacuum or in fluid.
"The trick is to avoid friction typically present in other forming techniques," Schroers says. "Blow molding completely eliminates friction, allowing us to create any number of complicated shapes."
In addition, the researchers say, blow molding combines three separate steps in traditional metal processing -- shaping, joining and finishing -- into one step, making previously cumbersome, time- and energy-intensive processing quick and easy.
"This could enable a whole new paradigm for shaping metals," Schroers says.