
Picture a metal that's so clever it can be blown into a mold like plastic materials, then think of the amazing gadgets that could be crafted from it—things that make Apple's unibody Macs look like child's play.
The advance is coming from research at Yale, where scientists have been working on what's called bulk metallic glasses (BMGs) and have perfected the technology to the point it's as useful, potentially, as everyday thermoplastics are today.
Metals are essentially crystalline on an atomic level. Their atoms, when in solid state, are arranged in pretty regular arrays, lined up neatly in rows and layers like the carbon atoms in a diamond. Glasses have long, stringy molecules that tangle together when they're liquid, and when they cool to a solid, they retain the tangled stringy structure, just frozen in place (very similar to plastics, just with different molecules). These different material characteristics are responsible for how they behave in everyday situations—metals (and plastics) are flexible, ductile and workable, while glasses are strong but fracture easily. Bulk metallic glasses are alloys of metals where the structure is randomly arranged, giving them some of the material powers of glass, and some of traditional metals.
The Yale advance has resulted in a new class of BMGs (made from a mix of metals including zirconium, nickel, titanium and copper) that can be blow-molded into shapes that are easily created using plastic or glass, but impossible using regular metals. They have the strength, resistance to impact, and durability of metal. The advance makes for speedier fabrication than with "normal" metals, since all the manufacturing steps happen at once—there's no need to shape, join, and finish as you'd require in even the cutting-edge metal fabrication processes that Apple uses to put its metal unibody Macs together. The trick has been to use novel materials, combined with low temperatures and low pressures that let the alloy soften and "flow" as it's shaped, without ever crystallizing like a normal metal.
What do you get as a result? The team's managed to make seamless metal bottles and resonators and shapes for biomedical implants. The material is stronger than regular steel and has costs similar to high-end steel products, but can be fashioned into products as cheaply as is possible with thermal extrusion of plastic.
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