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oai:www.ideals.illinois.edu:2142/82786 2023-07-11 col_2142_5131 col_2142_13836 com_2142_5130 com_2142_13835 com_2142_234

Robertson, Ian M. Clark, Blythe Gore 2015-09-25T20:53:01Z 2015-09-25T20:53:01Z 10000-01-01 2006 2006 This thesis examines two types of dislocation-obstacle interactions: dislocation-particle interactions during creep deformation, and dislocation-loop interactions during deformation at room temperature. Dislocation-particle interaction studies in Al-Zn-Mg-Cu-Zr, Al-4Mg-0.3Sc, and Al-0.3Sc showed that temperature, coherency, and particle size play a role in determining the dominant bypass mechanism, and that interactions are more complex than what is considered in current models. A new mechanism for elevated temperature bypass of particles during creep deformation was revealed, in which dislocations interact directly with the particle-matrix interface, altering the interfacial structure, and affecting subsequent dislocation interactions. These results are discussed in relation to macroscopic behavior in steady-state creep experiments. In addition, dislocation-loop interaction studies show interactions to be of two types: intersection and elastic interactions. In-situ observations show annihilation, rotation, and repulsion of loops due to dislocation interactions. Comparison with current molecular dynamics simulations highlights the need to better understand these interactions in order to improve models for irradiated materials. Made available in DSpace on 2015-09-25T20:53:01Z (GMT). No. of bitstreams: 2 license.txt: 4848 bytes, checksum: 96035ab3f5e1c23cc7138a224ce498bd (MD5) 3242826.pdf: 4464307 bytes, checksum: 65c5856d867d1d805408c6abc42934df (MD5) Previous issue date: 2006 Embargo set by: Seth Robbins for item 84067 Lift date: Forever Reason: Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs U of I Only 126 p. Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2006. http://hdl.handle.net/2142/82786 (MiAaPQ)AAI3242826 eng Engineering, Materials Science Dislocation -Obstacle Interactions in Aluminum Alloys text Materials Science and Engineering Materials Science and Engineering University of Illinois at Urbana-Champaign Dissertation Ph.D.