January_AMP_Digital

A D V A N C E D M A T E R I A L S & P R O C E S S E S | J A N U A R Y 2 0 1 8 1 1 Supercomputer simulations of the patterned material’s atomic architec- ture reveal that the nanotwin structures organize strain-related dislocations into linear bands called correlated necklace dislocations. Unlike dislocations in typi- Silicon atoms shown in color. Courtesy of Hideki Kawakatsu/University of Tokyo. cal metal—which get “tangled up” with each other under strain and cannot be undone, lead- ing to cumulative fatigue effects—the correlated necklace dislocations move parallel to one another. Because they do not block each oth- er’s motion, they slide back into place after strain relaxes, and no damage accumulates. brown.edu . FULL COLOR AFM Researchers at the University of Tokyo’s Institute of Industrial Science, Japan, devel- oped a novel approach to atomic force microscopy that allows material data to be visualized in full-color images. The Tokyo team developed a new way to move the tip of the atomic force micro- scope (AFM) so that it remains above Tiny crystalline structures called nanotwins can stabilize the effects of cyclical strain in such a way that damage does not accumulate within material grains. Courtesy of Gao Lab/ Brown University. the material surface in a position where the surface strongly influences its vibra- tional frequency. The technique yields three variables, which the researchers correlated with the colors red, blue, and green. “If the colors in the image are the same, we can say the signals come from the same type of atom and surround- ings,” explains postdoctoral researcher Denis Damiron. Linking the AFM tip height to the bottom of the frequency curve in the new technique allows measurements to be performed in a relatively short timeframe and prevents information loss. This method could allow re- searchers to examine the behavior of atoms in unprecedented detail. www.iis.u-tokyo.ac.jp.