Research staff member, T. J. Watson Center, Yorktown Heights, NY
Pages: 17 Published: Jan 1992
In addition to applications in engineering, the intrinsic mechanical damping of materials is important as a research tool. This is a consequence of the astonishing variety of mechanisms that produce damping, many of which provide a means of selectively probing structural features and kinetic processes on the atomic scale. In the study of thin-layer materials, the mechanisms of greatest interest are relaxation processes associated with the thermally-activated motion of defects and that are manifest experimentally as well-defined damping peaks. Examples are given of relaxations that operate on the macroscopic, microstructural, and atomic scales. These are taken from work on long- and short-range diffusion of hydrogen in amorphous alloys, grain-boundary sliding in metallic films, and point-defect reorientation in doped layers of silicon. New experimental approaches using the vibrating-membrane and vibrating-string configurations have been developed, and complexities associated with the mechanics of these arrangements are pointed out.
anelasticity, damping, internal friction, relaxation, thin films, thin layers, membranes, hydrogen, metallic glasses, aluminum, grain boundaries, silicon, point defects, internal stress, material damping, mechanical properties
Paper ID: STP17953S