Effect of microstructure and temperature on the intrinsic and extrinsic length scale dependence of plastic deformation in metals

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Metal components of increasingly smaller size are now being used in MEMS devices and microelectronic circuitry. These components are often subjected to high stress or local heating during service. The stress necessary to cause these components to plastically deform depends upon both intrinsic factors, inherent to the specific metal, and extrinsic effects imposed by geometrical constraint. The effect of microstructural features and temperature on the intrinsic and extrinsic length scale dependence of the plastic deformation is not well understood. The proposed research will perform a variety of nano-mechanical tests and electron microscopy investigations on sub-micrometer size specimens of pure gold, aluminum, and copper at temperatures up to 300 C to measure the effect of specific microstructural features, such as crystallographic orientation, impurity content, grain size and angular grain boundary misorientation, on the activation energies of the dislocation nucleation and glide processes that govern the plasticity of sub-micrometer size metal components.