Studies of Faceting by High Voltage/High Resolution Microscopy

Because numerous properties of materials, such as strength, fracture, creep, are influenced by internal interfaces, fundamental studies of the atomic structure of interfaces can ultimately lead to improvements in the performance of materials. With the advent of transmission electron microscopes with sub-2{Angstrom} resolution it became possible to make detailed comparisons between experimental images of the atomic structure of interfaces in close-packed metals and simulated structures predicted by theory. However, the stringent experimental conditions that must be satisfied for atomic resolution at interfaces is still a severe barrier to widespread application of the technique. In general, the optimum conditions for imaging interfaces are found only in specimens prepared by a long and tedious procedure involving orienting, cutting, cleaning and joining single crystals. The purpose of this paper is to describe the various ways in which interface structure is being studied in these materials.