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Bellon, Pascal Bellon, Pascal Averback, Robert S Trinkle, Dallas R Zhang, Yang Shu, Shipeng 2016-03-02T19:33:00Z 2016-03-02T19:33:00Z 2015-08-27 2015-12 We investigate the fundamentals of precipitate stability under energetic particle irradiation, towards the goal of better controlling the microstructures of driven alloys. First we focus on an irradiation-induced precipitatewithin- precipitate structure, which is referred to as “cherry-pit” structure. We show by computer simulation and analytical modeling that the formation of cherry-pit structure is a special instance of compositional patterning, and that the conditions for compositional patterning and the formation of cherry-pit structures are related, but different from each other. Then we develop a new kinetic Monte Carlo model, which includes the generation, recombination, and sink elimination of irradiation-induced point defects, as well as ballistic mixing. With this tool we explore the possibility of using point-defect sinks to alter the temperature range where compositional patterns are stable. This novel approach for optimizing radiation-resistant materials is then tested experimentally using a Cu-Ag-W model alloy. Lastly we show that the addition of a high density of W nanoparticles dramatically alters the coarsening behavior of precipitate-hardened Cu-Ag alloys. First, the nanoparticles suppress precipitate growth, but far more surprisingly they induce non-equilibrium Ag wetting layers on grain boundaries. This observation is explained using kinetic Monte Carlo simulations, which show that caging of Ag precipitates by the W nanoparticles suppresses their growth and drives the formation of the wetting layers. Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2016-03-02 without embargo terms The student, Shipeng Shu, accepted the attached license on 2015-08-26 at 22:37. The student, Shipeng Shu, submitted this Dissertation for approval on 2015-08-26 at 22:44. This Dissertation was approved for publication on 2015-08-27 at 14:17. DSpace SAF Submission Ingestion Package generated from Vireo submission #8675 on 2016-03-02 at 12:48:56 Made available in DSpace on 2016-03-02T19:33:00Z (GMT). No. of bitstreams: 2 SHU-DISSERTATION-2015.pdf: 3774355 bytes, checksum: 78757db43d7514de0786f84c317c4571 (MD5) LICENSE.txt: 4208 bytes, checksum: 9346520f9e7107bb7fd4a993fa66264a (MD5) Previous issue date: 2015-08-27 application/pdf http://hdl.handle.net/2142/88942 en Copyright 2015 Shipeng Shu self-organization irradiation Novel precipitate structures in alloys under irradiation text text Materials Science & Engineerng Materials Science & Engineering University of Illinois at Urbana-Champaign Dissertation Ph.D.