Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1573706 | Materials Science and Engineering: A | 2016 | 8 Pages |
Abstract
Nanostructured ferritic alloys are dispersion strengthened and imbued with remarkable neutron irradiation damage tolerance by an ultrahigh density of nano-oxide precipitates that must remain stable under prolonged high-temperature service. Here, previously reported long-time and high-temperature thermal aging data is used to derive a simple, but physically based and quantitatively predictive nano-oxide coarsening model using least square fits to equations representing different underlying mechanisms. A dislocation pipe diffusion model adequately fit the data with a dislocation-detachment climb mechanism providing the best fit. This model is consistent with microstructural observations and recently reported thermo-kinetic nano-oxide nucleation, growth and coarsening simulations that rationalize the underlying physics of coarsening. It is predicted that the nano-oxides will remain fully stable up to 900 °C. This remarkable coarsening resistance is due to the extremely low matrix solubility and diffusion rate of Y in equilibrium with Y2Ti2O7 that activates lower resistant paths along dislocations.
Related Topics
Physical Sciences and Engineering
Materials Science
Materials Science (General)
Authors
N.J. Cunningham, M.J. Alinger, D. Klingensmith, Y. Wu, G.R. Odette,