It's not Wolverine's Adamantium, but it's pretty damn close. Scientists have just developed a new hyper-strong metal alloy that's perfect for biomedical implants.
"It is about three to four times harder than most steels... and four times harder than pure titanium, which is what's currently being used in most dental implants and replacement joints," says Emilia Morosan, a physicist at Rice University in Texas, who lead the team of biomedical engineers and materials scientists that created the new alloy. The scientists unveiled their new metal this week in the journal Science Advances.
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The new alloy is "the hardest known bio-compatible [metallic] compound," ever created, Morosan and her colleagues write.
The new metal is composed of four parts pure titanium to one part pure gold, combined at scorching temperatures in a process called arc melting. As is often the case in materials science, Morosan and her colleagues stumbled across the recipe for the new metal by accident. They had been studying different combinations of titanium-gold metals, specifically those with near-equal ratios of titanium and gold.
To understand what made their new alloy so incredibly strong, Morosan and her team peered into the metal's atomic structure with electron microscopes. Morosan says one major key to the metal's fantastic properties is the dice-shaped cubic crystal structure of the metal.
At the center and on each of these cube's corners is a gold atom. Studded throughout the cube are titanium atoms, which latch onto three gold atoms each. That dense, symmetrical structure allows the metal alloy to stand up to intense pressures from all angles. Morosan's team discovered this unique structure is formed only at blazing high temperatures. Try to make it using a cooler process and you'll end up with a weak alloy of titanium-gold no harder than pure titanium. The new metal alloy is not only hard but also extremely resistant to gradual wear.
The researchers went into this project knowing that gold and titanium are two of the most bio-compatible metals available. Unlike copper or iron, which are frequently used in industrial alloys, these metals don't tend to kill off nearby human tissues, and the body usually won't reject the intruding metals and form scar tissue. That's why this new alloy is such a good candidate for prosthetics. After various cell culture tests, Morosan's team can safely say that today's metal is just as biocompatable as weaker versions of titanium that are already being used in biomedical implants.
"This material is well-suited for medical applications where titanium is already used, with some examples including replacement parts and components [such as knee and hip replacements], dental prosthetics, and implants," the scientists write.
How about claws? We're asking for a friend.