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oai:www.ideals.illinois.edu:2142/20816 2023-07-10 col_2142_5131 col_2142_13836 com_2142_5130 com_2142_13835 com_2142_234

http://hdl.handle.net/2142/20816 eng Copyright 1990 Sirois, Ernest Joseph, Jr Engineering, Metallurgy Engineering, Materials Science Hydrogen segregation, defects, and interactions with dislocations in nickel and aluminum text Birnbaum, Howard K. Sirois, Ernest Joseph, Jr. 2011-05-07T12:50:09Z 2011-05-07T12:50:09Z 10000-01-01 1990 Deformation experiments were performed to determine the effects of hydrogen and carbon on the activation parameters for dislocation slip in macroscopic nickel tensile specimens. The results show that hydrogen increases the dislocation mobility in Ni and in Ni-H alloys by reducing the activation enthalpy for dislocation motion and carbon reduces the mobility by increasing the enthalpy. Stress relaxation results show that the relaxation proceeds in three stages, which may be characterized by different activation areas. Secondary Ion Mass Spectroscopy experiments were performed to directly study the hydrogen (deuterium) distribution in several metal-hydrogen systems. Enhanced hydrogen (deuterium) concentration was observed at most grain boundaries, but not at coherent twin boundaries in Ni-H alloys which were exposed to low energy hydrogen (deuterium) plasma bombardment. Hydrogen (deuterium) was readily observed to segregate to a minority of grain boundaries in deformed, gaseous hydrogen charged, and low temperature aged Ni-H alloys. Small angle X-ray scattering experiments were performed to study hydrogen related defects in Ni-H and in Al-H alloys. Results for Al-H alloys show defects which exhibit anisotropic scattering, typical of platelet defects. Ni-H alloys show defects which exhibit isotropic scattering, suggestive of spherical void defects. Made available in DSpace on 2011-05-07T12:50:09Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 9114415.pdf: 5957706 bytes, checksum: bee58954b31133b452b102eaec2cc006 (MD5) Previous issue date: 1990 Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T14:46:29Z Item is restricted indefinitely. Restriction data tranferred 2014-07-01T11:20:51-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: ETDs are only available to UIUC Users without author permission ETDs are only available to UIUC Users without author permission U of I Only AAI9114415 (UMI)AAI9114415 Materials Science and Engineering Materials Engineering University of Illinois at Urbana-Champaign Dissertation Ph.D.