Acquisition of a Nano-Indenter for Moderately Elevated Temperatures

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9802716 Begley This award provides support to purchase a nano-indentation system which has the new feature of being in an environment chamber allowing tests to be made from -50 C to 100 C on technologically important materials. This instrument allows a wide variety of tests, including submicron-sized hardness tests, micro-scratch tests, the determination of damping properties via force-displacement measurements during cyclic indentation and constant load creep tests. The instrument will be heavily used by Institute of Materials Science members in several materials projects: (i) the measurement of individual layer properties in conventional and nanocrystalline thermal barrier coatings and nanocrystalline wear resistant materials, to provide both mechanical properties for modeling and the understanding of properties-microstructure-processing relationships coatings, (ii) the mapping of highly localized property changes due to aluminum depletion which leads to phase and stochiometry changes, (iii) the measurement of thin polymer properties at slightly elevated temperatures, (iv) the measurement of thin film properties in electronic devices at ambient and moderately elevated temperatures, (v) characterizing of mechanical property variations in systems experiencing interdiffusion between layers. Finally, the instrument will be used for advancing the understanding of properties revealed in experiments on the very fine scale of nano-indentation. It has been shown that the deformation characteristics (and hence, inferred mechanical properties) are influenced by length scales presumed to be governed by the characteristics of the microstructure. The interpretation of mechanical properties determined via indentation tests can not be separated from the fundamental problem of length-scale-dependent behavior. This work will extend current research in size-dependent indentation and collaborate with experts in processing, metallography and electron microscopy regarding sample preparation and characterization. Additionally, open issues remain on how to develop inelastic material properties from indentation tests, particularly those that are time-and temperature-dependent. These issues will be addressed in detail in on-going and future research programs. %%% ***