Micromechanics of Damage Accumulation in Micro- and Nano-Scale Laminates for Microelectromechanical Systems

: In this program we used a combination of microscale mechanical testing methods and nanoindentation to ascertain the deformation, fracture, and fatigue properties of the materials. A variety of materials characterization tools were then used to establish the chemistry)' and structure of the films. This study has revealed that the stability of nanograined metals, especially in the presence of cyclic loading, is poor in comparison to coarser (micron-scale) grained materials. Moreover, the future of microelectromechanical systems that contain nanograined noble metals and their long-term durability hinges on a thorough understanding of these phenomena and strategies to mitigate the degradation. Significant, additional studies will be required to mitigate this threat to the performance of MEMS in critical defense applications.