The Newest Invention: Rubbery Metal

What is that?

  A common combination: a metal bolt and a rubber collar to seal the area around it and to dampen vibrations
At a first glance, the association of the words "metal" and "rubber" seems to be at least illogical, if not absurd. The material properties of natural rubber that make it an elastomer and a thermoplastic are exactly the ones engineers try to avoid by using metal.

But metal has one problem, that makes scientists turn to plastic, in an effort to make the most of each material, by combining its elasticity with the rigidity of metal. Vibrations are a good example of this joint-venture.

They cause discomfort when using metal tools, they produce tiny cracks and dents in the metal and in the worst case scenario, they can affect the structural integrity of an entire building and could turn it into a pile of rubber.

The most widely used method of eliminating vibrations is to use some kind of suspension system that dampens them out and rubber is widely incorporated in this technology. Other techniques, which imply counteracting vibrations by producing another set, exactly opposite to the first ones, so that they cancel each other out, can also be used, but they are cumbersome and more expensive.

A new invention may be the ideal answer to this problem: the rubbery metal. This exotic material, developed by researchers from Virginia Polytechnic Institute and State University in Blacksburg, US, is a composite consisting of ceramic particles embedded in a metal matrix.

As the inventors claim, it makes use of the metal for the strength and stiffness and a strange property of ceramics, called ferroelasticity, which coverts vibrations into small rotations of crystals within the material.

Thus, the new composite material can offer all the positive properties of currently used metals and in the same time, the vibration-dampening properties of rubber. Many practical applications could incorporate this new product and many industry branches could benefit from using it, in the near future.

However, since some of them are highly susceptible when it comes to changes, like the skyscraper building and aircraft engineering, we will most likely see this material in more earthly applications, like wrenches, tennis rackets and baseball bats. At least for a while.

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By    23 Jul 2007, 13:04 GMT