Nanoindentation properties and the microstructure of grain boundary precipitate-free zones (PFZs) in an AlCuSiGe alloy |
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| Authors: | V Radmilovic C Taylor Z Lee A Tolley D Mitlin U Dahmen |
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| Institution: | 1. National Center for Electron Microscopy, Lawrence Berkeley Laboratory, MS-72 , University of California , 1 Cyclotron Rd., Berkeley, CA, 94720, USA VRRadmilovic@lbl.gov;3. Department of Mechanical Engineering , Virginia Commonwealth University;4. National Center for Electron Microscopy, Lawrence Berkeley Laboratory, MS-72 , University of California , 1 Cyclotron Rd., Berkeley, CA, 94720, USA;5. Department of Chemical and Materials Engineering , University of Alberta , Edmonton, Alberta, T6G 2G6, Canada |
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| Abstract: | We have characterized the nanoscale mechanical properties of grain boundary precipitate-free zones (PFZ's) in an AlCuSiGe alloy, using combined nanoindentation and in-situ atomic force microscopy (AFM). These mechanical properties were then correlated to the composition, precipitate distribution and, indirectly, to the vacancy concentration within these regions, as analyzed by transmission electron microscopy and spectroscopy. Using these results we constructed a structure-zone map of the area adjacent to the grain boundary, which relates the reduced elastic modulus and nanoindentation hardness of the alloy to its graded microstructure. Our analysis indicates that the lowest hardness was found in the region where no precipitates are present at all, regardless of solute concentration. In regions where precipitation is different from that of the bulk, somewhat inferior mechanical properties are achieved. |
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