Scientists Create Moldable Metal Like Plastic SteelMar 2nd, 2011 | By Eli Johnson | Category: Technology and Science
Yale scientists have created a substance that combines the strength of steel with the moldable properties of plastic, Materials Today revealed last week. The new class of substances, called bulk metallic glasses (BMGs), enables a few minutes of blow molding to create objects twice as strong as steel, in shapes like metallic bottles, watch cases, miniature resonators, and biomedical implants. Experts anticipate the invention will be as revolutionary as the creation of synthetic plastic.
Traditional metals derive their strength from an orderly crystalline structure. Reshaping this rigid structure requires three separate steps to process the raw metal into finished materials: shaping, joining, and finishing.
BMGs are amorphous metals that have randomly arranged atoms and a low critical cooling rate. This allows shaping, joining, and finishing to be combined into one blow-molding process that takes less than a minute.
A key to the success of the process is maintaining an ideal temperature and minimal friction, which researchers achieved by shaping materials in a vacuum or a fluid. “The trick is to avoid friction typically present in other forming techniques,” said research team member Jan Schroers. “Blow molding completely eliminates friction, allowing us to create any number of complicated shapes, down to the nanoscale.”
The speedier process saves not only time, but also energy and money. The different metals used to make BMG alloys, such as zirconium, nickel, titanium and copper, cost approximately the same as high-end steel. But they can be processed as cheaply as plastic.
The Yale team has already manufactured a wide range of shapes and gadgets using the new processing method, including applications as sophisticated as miniature resonators for microelectromechanical systems (MEMs) and gyroscopes. They anticipate this will lead to many new applications and a revolution in metallurgy.
“This could enable a whole new paradigm for shaping metals,” Schroers said. “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.”