A framework is developed that models point defect diffusion and interaction with pre-existing microstructures during irradiation, including defect-defect interactions and defect sinks. This framework uses a modified diffusion potential that includes not only defect concentration, but also intrinsic stresses from the pre-existing microstructure. Various microstructures are studied in {Fe} by using this framework in numerical simulations with an approach similar to a phase field model. Grain boundaries are represented via disclination mechanics, and microcracks are represented using the Griffith crack model. For dislocation loops and grain boundaries, point defect sink efficiency is found to correlate with sink density. For triple junctions, sink efficiency is heavily dependent on defect type; equiaxed grains were found to be more efficient at vacancy removal than elongated grains, whereas sink density was once again the dominant parameter for interstitials. For crack tips, simulations suggested that vacancies begin accumulating above a critical stress intensity factor, suggesting premature crack propagation via void formation during irradiation.

Creator

• Zarnas, Patrick

DOI

• https://doi.org/10.21985/n2-wk3s-d317

Subject

• Materials Science
• Mechanical engineering
• Nuclear engineering

Language

• en

Alternate Identifier

• http://dissertations.umi.com/northwestern:15639
• etdadmin_upload_831637

Keyword

• Grain boundaries
• Voids
• Point defects
• Radiation
• Crack tip
• Triple junctions

Date created

• 2021-01-01

Resource type

• Dissertation

Rights statement

• In Copyright