Writing in the March 7 issue of the journal "Science," researchers from The Johns Hopkins University and the U.S. Army Research Laboratory say they have discovered why boron carbide, sometimes used in protective armor, experiences a loss of impact resistance. By observing the atomic structure of boron carbide fragments retrieved from a military ballistic test facility, the team discovered that higher-energy impacts cause tiny bands of boron carbide to change into a more fragile glassy form. Having found why boron carbide loses its protective capabilities, the researchers hope they have opened a door toward development of a new form of the material that will do a better job of keeping soldiers and police officers safe. "We intend to try modifying the material's grain structure, its chemistry and the additives used in making it," said James W. McCauley, a senior research scientist at the Army Research Laboratory at Aberdeen Proving Ground in Maryland and a co-author of the journal article. "The goal will be to have the amorphization occur at higher impact pressures. Then the armor would provide better protection against a wider range of threats."

For more information, visit http://www.me.jhu.edu or http://www.arl.army.mil .