Amorphous metal combines high strength
with ease of processing
Medical Product Manufacturing News, March 2003
Imagine a metal alloy whose strength exceeds that of steel and titanium, but
that can be processed like a plastic. Sound far-fetched? Not to the people at
Liquidmetal® Technologies (Tampa, FL; www.liquidmetal.com).
A zirconium-based alloy marketed by the company exhibits 2.5 times the strength of
some titanium alloys and twice the strength-to-weight ratio of some aluminums.
In addition to these exceptional characteristics, the alloy can be cast into net-shaped forms that significantly
reduce the need for secondary finishing processes.
The secret to this innovation lies in the alloy's amorphous structure that eliminates the inherently weak spots
found at molecular grain boundaries.
"All metals have an amorphous structure in their liquid state," says vice president of medical products Barry Canon.
"But our alloy retains this characteristic in its solid state, essentially making it like a metallic glass."
Other physical benefits that result from this amorphous structure include a
2% elasticity and twice as much hardness as some stainless steels.
The lack of phase transformation during solidification also holds benefits from processing.
With a lower melting machining operations. Because it does not crystallize, the surface finish of parts made from
the alloy is smoother and more consistent than that of die-castings.
Combine all of these characteristics with bio-compatibility and resistance to corrosion and wear,
and it is easy to see why some companies are seeing applications for the alloy in the medical field.
Surgical Specialties Corp.(Reading, PA; www.surgicalspecialites.com), for instance, began producing ophthalmic scalpel blades using
Liquidmetal® technology in the third quarter of 2002. Another company, Depuy Orthopedics Inc.
(Warsaw, IN; www.depuy.com), recently began using the alloy to produce knee-replacement devices.
other possible product applications include pacemaker casings and medical instruments.
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