About this Abstract |
Meeting |
MS&T22: Materials Science & Technology
|
Symposium
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Tackling Structural Materials Challenges for Advanced Nuclear Reactors
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Presentation Title |
Microstructural Self-organization of Phase-separating Alloys during Irradiation into Global Compositional Patterns at Grain-Boundaries and Inside Grains |
Author(s) |
Pascal M. Bellon, Gabriel F Bouobda Moladje, Sourav Das, Soumyajit Jana, Robert S Averback |
On-Site Speaker (Planned) |
Pascal M. Bellon |
Abstract Scope |
Nanoscale compositional patterns (CP) can be stabilized during irradiation in phase-separating alloy systems due to the competition between finite-range ballistic mixing and thermodynamically-driven decomposition. Here we extend past results on bulk patterning by studying CP at grain boundaries (GBs). We introduce a phase-field model to investigate the coupled evolution of concentration inside grains and at symmetric tilt grain boundaries, described as arrays of edge dislocations. In phase-separating binary alloys that undergo inverse Kirkendall effects due to vacancy-solute flux coupling, we show that irradiation-induced segregation competing with finite-range ballistic mixing can result in CP at grain boundaries. Furthermore, GB compositional patterning can co-exist with bulk patterning. These results are extended to segregation and precipitation on dislocation loops. These predictions are compared to past experimental results on precipitate evolutions in irradiated Ni-based alloys, and to new results in Al alloys. Consequences on hardness and microstructure stability under irradiation are discussed. |