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oai:www.ideals.illinois.edu:2142/99175 2023-07-11 col_2142_5131 col_2142_14837 com_2142_5130 com_2142_14836 com_2142_234

Trinkle, Dallas R. Trinkle, Dallas R. Bellon, Pascal Averback, Robert S. Zhang, Yang Heuser, Brent J. Li, Zebo 2018-03-13T15:20:58Z 2018-03-13T15:20:58Z 2020-03-14T09:15:19Z 2017-09-06 2017-12 During the last decade, studies have focused the development of creep-resistant alloys that can tolerate the high temperatures and high irradiation doses within nuclear reactors. One important mechanism of irradiation creep is the migration of dislocations, which arises as a direct consequence of point-defect diffusion near dislocations and is also affected by the presence of solutes. In this work, we develop a multi-scale model which is able to simulate the diffusion of point-defects and solute atoms in the dislocation strain field. We first use kinetic Monte Carlo simulations to investigate the strain effects on the transport coefficients for vacancies and Si in FCC Ni. We then use a mesoscale model, which takes the strain-dependent transport coefficient computed by self-consistent mean field calculations, to model the irradiation induced solute segregation around an $\frac{a}{2}[1\bar{1}0](111)$ edge dislocation in FCC Ni-Si alloy. At last, we extend the mesoscale model into an multi-scale approach by coupling it to a discrete model which captures the thermally activated atomic transitions and reactions in the dislocation core. We use the multi-scale approach to investigate the climb motion of an $\frac{a}{2}[1\bar{1}0](111)$ edge dislocation in FCC Ni-Si alloy, induced by irradiation and by an externally applied stress. We also quantify the effect of solute on the climb velocity. Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2019-12-01 The student, Zebo Li, accepted the attached license on 2017-09-05 at 15:03. The student, Zebo Li, submitted this Dissertation for approval on 2017-09-05 at 15:13. This Dissertation was approved for publication on 2017-09-06 at 15:32. DSpace SAF Submission Ingestion Package generated from Vireo submission #11634 on 2018-03-13 at 09:54:54 Made available in DSpace on 2018-03-13T15:20:58Z (GMT). No. of bitstreams: 2 LI-DISSERTATION-2017.pdf: 16323645 bytes, checksum: 96db40128fed400cf5818bd6724deccf (MD5) LICENSE.txt: 4204 bytes, checksum: c85f02dd2445690b49525140727b01b3 (MD5) Previous issue date: 2017-09-06 Embargo set by: Seth Robbins for item 105137 Lift date: 2020-03-13T15:21:19Z Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD system Embargo set by: Seth Robbins for item 105137 Lift date: 2020-03-13T15:25:40Z Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD system Embargo set by: Seth Robbins for item 105137 Lift date: 2020-03-13T15:28:52Z Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD system U of I Only Restriction Lifted for Item 105137 on 2020-03-14T09:15:19Z. application/pdf http://hdl.handle.net/2142/99175 en Copyright 2017 Zebo Li Dislocation, climb, diffusion, point defect, solute segregation Multi-scale investigation of vacancy-mediated diffusion of Si in Ni near an edge dislocation text text Nuclear, Plasma, & Rad Engr Nuclear, Plasma, Radiolgc Engr University of Illinois at Urbana-Champaign Dissertation Ph.D.