Courtesy of Naoya Shibata/ Nion.com/ Pixon.com and the Department of Energy, Division of Materials Sciences
A superresolution micrograph showing individual atoms (bottom) makes it possible to model the exact crystal structure (top).
An electron microscope that generates exceptionally clear views of atoms may allow scientists to create novel materials or detect atomic-scale defects. The device illuminates its target with an electron beam and detects the dispersed electrons or X-rays given off in response. The lens manufacturer Nion Co. in Kirkland, Washington, has found a way to tighten the beam so that atoms situated behind other atoms are clearly visible, as are heavy-metal atoms that were previously undetectable. Physicists at Oak Ridge National Laboratory in Tennessee are already using the microscope to identify the atomic arrangements that yield strong, heat-resistant ceramics.
Materials scientists at Lehigh University in Pennsylvania hope to have another high-precision microscope up and running this fall. They will use it to study minute defects such as brittle failure, an atomic-scale weakening of metal. Brittle failure may be the underlying cause of such disasters as the Titanic and 19 World War II ships that broke in half while docked. “Sometimes the presence of only a few parts per million of the wrong element can cause steel or copper to snap,” says David Williams, a materials scientist at Lehigh. Soon he may understand how to stop that from happening.