2026-09-22T13:25:20Z https://www.ideals.illinois.edu/oai-pmh

oai:www.ideals.illinois.edu:2142/72996 2023-07-11 col_2142_5131 col_2142_13836 com_2142_5130 com_2142_13835 com_2142_234

Bellon, Pascal Averback, Robert S. Bellon, Pascal Averback, Robert S. Zuo, Jian-Min Dillon, Shen J. Zhang, Xuan 2015-01-21T19:55:27Z 2015-01-21T19:55:27Z 2017-01-22T10:15:21Z 2014-12 2015-01-21 2014-12 Microstructural stability of nanostructured alloys under harsh environments such as high temperatures and high dose irradiation is a primary concern in the deployment of those materials for engineering applications. This thesis work explores several pathways to stabilize nanostructures in Cu-based ternary alloy systems, which contain a very small fraction of refractory alloying element (W) that is highly immiscible with Cu. Three systems with distinct interaction energies have been investigated. 1) In the Cu-Nb-W system, where Nb is moderately immiscible with Cu but is miscible with W, very stable Nb-rich core/W-rich shell nanoprecipitates form upon annealing, as a result of the competition between thermodynamics and kinetics of Nb and W in Cu. When samples are first subjected to room temperature irradiation, however, W-rich core/Nb-rich shell nanoprecipitates form instead. These nanoprecipitates display even stronger resistance to thermal coarsening, which is rationalized by the very high trapping efficiency of ramified W cores for Nb atoms. 2) In the Cu-Ag-W system, where Ag is moderately immiscible with Cu and is highly immiscible with W, compositional patterning, as a steady state of the system under irradiation, can be extended to much higher temperatures by first using room temperature irradiation to introduce W nanoprecipitates, which then serve as sinks for point defects during elevated temperature irradiation. 3) In the Cu-Ni-W system, where Ni is miscible with Cu with a small positive heat of mixing but tends to form compound with W, irradiation-induced W nanoprecipitates force the Ni atoms out of solution during annealing, forming Nb-W compound, and the system evolves towards the same steady state during room temperature irradiation, regardless of the initial state. The work contains both experimental and computational studies. Item withdrawn by Laura Spradlin (lspradl2@illinois.edu) on 2014-08-07T21:22:04Z Item was in collections: University of Illinois Theses & Dissertations (ID: 1) No. of bitstreams: 1 Zhang_Xuan.pdf: 7531466 bytes, checksum: ec6024a02b4d55a4f036b97f553d28f7 (MD5) Made available in DSpace on 2015-01-21T19:55:27Z (GMT). No. of bitstreams: 1 Xuan_Zhang.pdf: 7527382 bytes, checksum: 7c40d6ca7dffcfb63a91ac35aeb461e5 (MD5) Embargo set by: Seth Robbins for item 73185 Lift date: 2017-01-21T19:56:18Z Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD system U of I Only Restriction Lifted for Item 73185 on 2017-01-22T10:15:21Z. http://hdl.handle.net/2142/72996 en Copyright 2014 Xuan Zhang Metal Alloy Nanoscale Self-organization Irradiation Transmission Electron Microscopy (TEM) Monte Carlo simulation Nanoscale self-organization in irradiated ternary alloys text Materials Science & Engineerng 1919 Materials Science & Engr 0130 University of Illinois at Urbana-Champaign Dissertation Ph.D. PHD:Materials Sci & Engr -UIUC 10KS0130PHD