Ceramic rebounds from stressful situations. (Materials Science).

Say the word ceramic and many people think of teacups or plates that shatter when dropped. Although scientists value high-quality ceramics, such as those used to shield spacecraft from heat, for their combination of heat resistance, stiffness, and lightness, even these ceramics are brittle and difficult to cut or drill without breaking.

Recent experiments reveal that an unusual ceramic material, titanium silicon carbide ([Ti.sub.3]Si[C.sub.2]), can fully recover after being compressed with a stress that would leave most ceramics shattered and most metals permanently deformed. The studies also indicate that the ceramic readily dissipates energy, meaning that it could be useful for damping vibrations in machinery. In the February Nature Materials, Michel W. Barsoum of Drexel University in Philadelphia and his coworkers describe repeatedly putting cylinders of the new ceramic under stresses of 1 gigapascal, or about 10,000 times atmospheric pressure.

The newly reported properties of this ceramic could make it a standout material for a variety of applications, from less-wobbly disk drives to quieter tools, says Barsoum.

In previous studies of this ceramic, Barsoum and his colleagues had found that it has other unusual properties. It's easily machined with an ordinary drill or saw, and it won't shatter at temperatures far beyond those that would destroy other ceramic materials.

Barsoum says that [Ti.sub.3]Si[C.sub.2] is just one member of a large family of unusual ceramics, and further studies may reveal related materials with even better properties.--J.G.