In the March issue of the Journal of the Minerals, Kenneth S. Vecchio of University of San Diego, California has described a new metallic laminate (composed of layers of one of more kind of metals) which has certain unique properties. The metal is made of alternating layers of Aluminum and Titanium alloy foils, compressed and heated in an inexpensive energy-conserving process. It can serve as armor, and also as a replacement for beryllium, a strong but toxic metal commonly used in demanding aerospace applications.

Good results with ballistics tests (Courtesy: University of San Diego)The new material we developed is environmentally safe, and while its stiffness equals that of steel, it’s only half as dense. It has a hard ceramic-like intermetallic layer of Titanium Aluminide, and a pliable layer of residual Titanium alloy. The layers can be stacked like 1-millimeter-thick pages of a book, and even contoured into desired shapes prior to heating. This gives the metal excellent armor properties: a heavy Tungsten alloy bullet fired into a three-quarters-inch (2 cm) thick sample at a velocity of about 2,000 mph (900 m/s) penetrated only half the thickness of the test sample!
Interestingly, the laminate architecture was chosen to mimic the internal structure of the tough shell of the red abalone! This is another example of science getting inspired by what is already available in Nature. Researchers are currently studying structural and functional designs of everything from mollusk shells and bird bills to sea urchin spines and other biocomposites in the development of new smart materials and devices.
According to Professor Vechhio, it might be possible to include electrical pathways within the laminate, and thus create piezoelectric sensors within the metal. This will be immensely useful, for example in case of a body armor, as the sensors can provide real-time data about the status of the soldier and the armor to the commanders in the field. These materials can also deform when electricity is applied, and this might have applications in robotics to create artificial muscles :).